Programme

Friday, 28th February

1900–2000 The 1980 eruption of Mount St. Helens: a 40-year perspective

Prof. Katherine Cashman

Saturday, 29th February

0905–0920 Paragenesis of Gold at Avoca: Implications for Exploration in Caledonian Terranes of Southeast Ireland

S.H. McClenaghan, F. Drakou, and T. Riegler

0920–0935 Linked crystallization and wall rock Interaction in spodumene pegmatites, with exploration implications

J.F. Menuge, R. Barros and D. Kaeter

0935–0950 Glacial deposits in Connemara, dated with cosmogenic 10Be, document melting of terrestrial ice in Western Ireland during Heinrich Stadial 1

A. Foreman, G. Bromley and B. Hall

0950–1005 Remote Sensing for Monitoring and Mapping Karst Groundwater Flooding in the Republic of Ireland

T. McCormack, J. Campanyà, O. Naughton

1005–1020 Investigating the Significance of Groundwater Pathways in Radon Transportation

L. Collins, V. Gallagher, M. Glennon, J. Hodgson, and K. Tedd

1020–1035 Potential of machine learning in linking national airborne radiometric data to soil class mapping

D. O’Leary, P. Touhy, P. Mellender, O. Fenton, E. Daly, C. Brown

1035–1100 Coffee and posters

1100–1115 Insights into the basin evolution and structural framework of the Carboniferous of South-Central and SE Ireland

K. Torremans, J. Güven, R. Doyle, J. Conneally, N. Vafeas, E. Dunlevy, J.J. Walsh

1115–1130 Testing the impact of fault growth models on syn-rift stratigraphy using forward stratigraphic modelling

E. O’ Donnell, P.D.W. Haughton, L. Amy, C. Childs, C. Griffiths

1130–1145 Regional chemostratigraphic correlation of Irish Carboniferous volcanic ash horizons – an integrated approach

H.A. Koch, D. Chew, M. Philcox, B.S. Kamber

1145–1200 Large Igneous Province volcanism and carbon release as cause for Early Jurassic Global Change Events

M. Ruhl, S.P. Hesselbo, H.C. Jenkyns, W. Xu, A. Al-Suwaidi, R.L. Silva

1200–1215 Csővár revisited: new geochemical data to the integrated stratigraphy of a Triassic-Jurassic boundary section in the western Tethys

E.B. Kovács, M. Ruhl,A. Demény and J. Pálfy

1215–1230 The History of Life project: student film-making as a tool for enhanced learning

J. Murray, T. Henry, L. Ní Dhonnchadha, B. McSharry, G. McGrath, I. Mac Labhrainn and S. Flynn

1230–1330 Lunch

1330–1345 Spatial and Temporal Variations in the Geochemistry of the River Shannon

A.E. Carey, S.A. Welch, C.B. Gardner, D.F. Smith, P. Croot, T. Henry, and W.B. Lyons

1345–1400 Provenance of Mesozoic sediments in the North Celtic Sea and Saint Georges Channel Basins: Results from Detrital Zircon and Apatite studies

O. McCarthy, P. Meere, D. Chew, B. Fairey

1400–1415 Temporal Variability of Cold-water Coral Habitats from the Porcupine Bank Canyon NE Atlantic: Preliminary Results

L. O’Reilly, A. Lim, J. Titschack, O.J. O’Connor, J. Appah, K. Harris, L. Macedo, R. Strachan and A. Wheeler

1415–1430 An Investigation of the impacts of Termination 5 on Thermohaline Circulation in the Eastern North Atlantic

M.J. Curran, A. Morley

1430–1445 Seismic signature of the North Atlantic climate fluctuations

F. Le Pape and C. J. Bean

1445–1500 Global Megadrought? Perspective on the size and extent of the 4.2kyr event, and its impact on the Harappan civilization, from stalagmite geochemistry around the Indian Ocean

N. Scroxton, S.J. Burns D. McGee, L.R. Godfrey, L. Ranivoharimanana, P. Faina

1500–1530 Coffee and posters

1530–1545 Origin of rare eclogite clasts in a chondritic meteorite

I. Sanders

1545–1600 A novel multi-shot laser ablation protocol: minimising sampling volume and LIEF

E. Corbett, A. Simonetti, P. Shaw, L. Corcoran, Q. Crowley, B. Hoare

1600–1615 Sr isotopes indicate very rapid (~103 yr) formation of metal-rich layers by reactive melt percolation in an open-system layered intrusion

J.S. Daly, L.N. Hepworth, B. O’Driscoll, C.G. Johnson, R. Gertisser and C.H. Emeleus

1615–1630 Regional assessment of groundwater resources in the greater Dublin area

N. Duncan, K. Tedd, S. Carey, D. Doherty, J. Greene, C. Kelly, M. Lee, R. Meehan, A. Pilmer and S. Raymond

1630–1645 Separating diffractions pre- and post-migration with deep learning

B. Lowney, I. Lokmer, G.S. O’Brien, C.J. Bean

1645–1700 The emerging field of Agri-Geophysics – A future in Ireland?

E. Daly, C. Brown, P. Touhy, P. Mellender, O. Fenton

1700–1800 Coffee and posters

1800–1900 The geological Anthropocene is real

Prof. Mark Williams

Sunday, 1st March

0915–0930 Testing a Negative Carbon Emissions Technology via enhanced plant mediated chemical weathering

W. Xu, C. Yiotis, B.S. Kamber, L.W. Gill, J. Knappe, T. Riegler, J.C. McElwain

0930–0945 Using Compositional Data Analysis (CoDA) to characterise groundwater geochemistry in the vicinity of Lisheen Mine, County Tipperary, Ireland

S. Wheeler, T. Henry, J. Murray, L. Morrison and Frank McDermott

0945–1000 Uranium in groundwaters from the Leinster Granite, SE Ireland

F. Papageorgiou and F. McDermott

1000–1015 Appinite suites and their genetic relationship with coeval voluminous granitoid batholiths

J.B. Murphy

1015–1030 Probabilistic Surface Heat Flow Estimates Assimilating Palaeoclimate History: New Implications for the Thermochemical Structure of Ireland’s Crust

B. Mather, T. Farrell and J. Fullea

1030–1045 Project DIG: De-risking Ireland’s Geothermal Potential

D. Kiyan, B. O’Reilly, C. J. Bean, J. Fullea, S. Lebedev, P. Meere and the DIG team

1045–1115 Coffee and posters

1115–1130 A synopsis of Geopark geologist research from County Clare

Eamon Doyle

1130–1145 3D data for monitoring change in coastal regions

K. Craven, J. Barry, R. O’Toole and S. Cullen

1145–1200 Locating flowing conduits in Irish Karst using ground vibrations

H.K. Ali, C.J. Bean, C. Hickey, B. O’Keeffe

1200–1215 Uvalas and their relationship to sinkholes (dolines) in an evaporite karst setting

R.A. Watson, E.P. Holohan, D. Al-Halbouni, H. Alrshdan, D. Closson and T. Dahm

1215–1230 Taphonomy of anurans from the Eocene Geiseltal Konservat-Lagerstätte

D. Falk, O. Wings and M.E. McNamara

1230–1245 Ireland’s dinosaurs

M.J. Simms and D. Martill

1245–1345 Lunch

1345–1400 The application of machine learning methods to aggregate geochemistry predicts quarry source location: a case study from the Irish aggregate industry

T. Dornan, G. O’Sullivan, N. O’Riain, E. Stüeken, R. Goodhue

1400–1415 Crustal structures at Rockall Trough by Full waveform inversion

G. Tomar, C.J. Bean and S.C. Singh

1415–1430 Passive seismic exploration: Detecting subsurface interfaces using the ambient noise cross-correlation

Y. Xu, S. Lebedev, R. Bonadio, T. Meier, C. Gomez-Garcia, C. J. Bean, D. Hariri, M. Rezaeifar and the PACIFIC Team

1430–1445 Characterization of beach dune evolution from Blackwater to Wexford Bay, Co. Wexford using Geophysical and remote sensing approaches

S. Mathew, C. Gallagher, X. Pellicer, X. Monteys

1445–1500 Assessing groundwater resources using Tellus airborne electromagnetics

Y. O’Connell, C. Brown, T. Henry, L. Morrison and E. Daly

1500–1515 New Tellus Geophysical Data for southeast Ireland and electromagnetic inversion results from Limerick region

R. Scanlon, B. McConnell, M. Ture, M. Muller and J. Hodgson

The 1980 eruption of Mount St. Helens: a 40-year perspective

Prof. Katherine Cashman University of Bristol

The 1980 eruption of Mount St. Helens changed the study of volcanic processes, hazards and risk in many important ways. Most important at the time were the detailed instrumental, photographic, remote sensing and eyewitness observations of the climactic eruption, which have provided a rich resource for further study. Importantly, eruptive activity then continued through 1986, and resumed again between 2004 and 2008, providing an evolving view of the magmatic system, as well as allowing time for innovations in both monitoring and sample analysis. From the perspective of 40 years later, I will examine all of these features, and place them in the context of new models of how volcanoes work.

Invited Guest Lecture

28th February at 7pm

The geological Anthropocene is real

Prof. Mark Williams University of Leicester

People have become agents of global geological change. Each year we move much more sediment than all of the world’s rivers, use enough freshwater to drain the African Great Lakes Malawi and Victoria dry, add billions of tons of carbon dioxide to the atmosphere, and use more than 500 exajoules of energy from primary resources like oil, gas and coal. Humans have reshaped the global pattern of life, translocating plants and animals beyond their natural ranges, appropriating much of the energy produced by plants, and concentrating mass in a small range of organisms – 7.7 billion humans – and their commensal organisms like chickens, cows and maize. Whilst the fossil record of archaic humans extends back nearly 3 million years, for much of that time patterns of human influence were regional, beginning in Africa, and only over many tens of thousands of years expanding throughout the world to leave behind a time-transgressive fossil signature, mostly of artefacts, but later including translocated species and patterns of organism extinction. However, from the mid-20th century onwards the accelerating signature of human global consumption can be demarcated by the spread of, for example, plastics, radiogenic isotopes from nuclear detonations, fly ash from thermal power stations, invasive species such as the giant African snail or Pacific oyster, and the globally traded materials that build our modern cities. These leave a clear and distinctive geological signature of human over-consumption of Earth resources, and of a geologically distinctive Anthropocene.

Invited Guest Lecture

29th February at 6pm

Abstracts of Oral Presentation

in order of programme

Titles marked with * are eligible for student prize

Paragenesis of Gold at Avoca: Implications for Exploration in Caledonian Terranes of Southeast Ireland

S.H. McClenaghan (mcclens@tcd.ie), F. Drakou, and T. Riegler

Department of Geology, Trinity College Dublin, Dublin 2, Ireland; Irish Centre for Research in Applied Geosciences

The Avoca Cu-Zn-Pb-Ag VMS belt in southeast Ireland comprises a SW-NE Caledonian trend of Ordovician volcano-sedimentary rocks that host over 16 Mt of sulphides (0.6% Cu) distributed in six defined orebodies. The Kilmacoo Au Zone, on the northeast extremity of the Avoca belt comprises a resource of 300,000 tonnes at 1.5 g/t Au, containing discrete phases of visible (free) electrum associated with late Caledonian structures. Although historically mined for Cu, notable resources of Zn, Pb and Ag remain at Avoca occurring as syn-sedimentary stratiform pyritic lenses that sit conformably within the host volcano-sedimentary stratigraphy. Sulphides have been modified by early Caledonian shearing, which has resulted in ductile attenuation of sulphides during greenschist facies metamorphism. This has resulted in recrystallization of early primary pyrite with the development of meta-blastic overgrowths and discrete porphyroblasts of pyrite. Gold contents in the Avoca VMS deposit are low overall, occurring as a minor refractory phase in pyrite (Avg., 0.29 ppm) and arsenopyrite (0.33 ppm). At Kilmacoo, auriferous banded (ribband) quartz units are seen to be cutting penetrative D1 fabrics which postdate sulphide deposition and structurally modify their distribution. This would suggest that the Kilmacoo Au Zone is not related to primary zonation within the Avoca VMS system, but associated with a separate distinctly late paragenesis. This has implications sources of gold in southeast Ireland, with late shear structures post-dating D1 penetrative cleavages exerting a control on the concentration of Gold.

Linked crystallization and wall rock Interaction in spodumene pegmatites, with exploration implications

Julian F. Menuge1 (j.f.menuge@ucd.ie), Renata Barros2 and David Kaeter3

1 School of Earth Sciences, University College Dublin, Belfield, Dublin 4.

2 iCRAG, University College Dublin, Belfield, Dublin 4.

3 Present address: Geological Survey of Belgium, Brussels, Belgium.

Spodumene pegmatites are globally important sources of lithium and tantalum, and are enriched in tin, rubidium and caesium. Chemical interactions between pegmatite magmas and their immediate wall rocks have often been overlooked in pegmatite research. We summarize our work on the mineralogy, texture and chemical composition of spodumene pegmatites and their wall rocks from south Leinster. LA-ICP-MS chemical mapping shows that the distribution of tin, tantalum, and other high field strength elements in pegmatites is controlled by their partitioning and varying mineral stability in two types of granitic magmas and an endogenous hydrothermal fluid that unmixed during pegmatite crystallization. Whole-rock chemical analysis of drill cores reveals that a variable, but often large (tens of percent), proportion of Li, Ta, Cs and other rare elements is commonly lost from spodumene pegmatite to wall rock, forming geochemical halos. We propose that pegmatite crystallization, and chemical exchange between pegmatite magma and wall rocks, are linked processes: hydrothermal fluid that unmixes from crystallizing pegmatite magma is largely expelled into wall rocks. Early pegmatite minerals, including spodumene, break down in contact with evolved magma and hydrothermal fluid. These processes reduce Li, but often increase Ta, economic potential. Geochemical halos should be used with caution in exploration because intense halos might surround pegmatites that have lost most or all of their spodumene by hydrothermal alteration. Chemical mapping of stream sediment heavy mineral concentrates may provide an improved method to locate spodumene pegmatites, and especially economic concentrations within them of Ta, Sn and other rarer metals.

Glacial deposits in Connemara, dated with cosmogenic 10Be, document melting of terrestrial ice in Western Ireland during Heinrich Stadial 1*

A. Foreman1 (a.foreman1@nuigalway.ie), G. Bromley1, and B. Hall2

1 NUIG School of Geography, Archaeology, and Irish Studies; NUI Galway; Galway.

2 School of Earth and Climate Sciences; University of Maine; Orono, Maine.

During the Last Glacial Maximum, the terrestrially based Connemara ice dome was one of several principal ice accumulation centres in western Ireland, distributing ice radially and terminating along its western margins in the North Atlantic Ocean. Our new beryllium-10 chronology, constrained with surface-exposure ages of erratics on a longitudinal coast-to-interior transect, demonstrates that post-LGM deglaciation of Connemara was rapid and that the ice dome was gone by ~17.4 ka. Coupled with the abundance of landforms in this mountainous region indicative of glacial meltwater production, we interpret the rapid and early deglaciation of Connemara as reflecting pronounced melting during the summer ablation season driven by strong atmospheric warming. While this model contrasts with the traditional view of Heinrich stadials as periods of intense cold in the North Atlantic, we note similarities with glacial records from elsewhere in the Northern Hemisphere and globally, as well as with recent marine-geologic evidence for enhanced melting of European ice sheets during Heinrich stadials. Further tests are under way using multiple proxies to refine this new model.

Remote Sensing for Monitoring and Mapping Karst Groundwater Flooding in the Republic of Ireland

Ted McCormack1 (ted.mccormack@gsi.ie), Joan Campanyà1, Owen Naughton1,2

1 Geological Survey Ireland, Beggars Bush, Haddington Road, Dublin, Ireland

2 Department of Built Environment, Carlow Institute of Technology, Ireland

3 Tobin Consulting Engineers, Block 10-4, Blanchardstown Corporate Park, Dublin 15

Karst related groundwater flooding represents a significant hazard in many rural communities in Ireland. A series of unprecedented flood events in recent years have reinforced the need to improve our ability to quantify the location and likelihood of flood occurrence. Geological Survey Ireland, in collaboration with Carlow Institute of Technology and Trinity College Dublin, has established a collaborative project to investigate groundwater flooding, with particular emphasis on seasonal karst lakes known as turloughs. There are over 400 recorded turloughs across Ireland, the majority of which located on limestone lowlands. Turloughs can completely dry during summer months but extend to hundreds of hectares during the winter flood season. The practical limitations of establishing and maintaining a network of over 400 turloughs supported the use of remote sensing and GIS techniques to delineate flood extents and monitor flood prone areas using satellite imagery such as of the ESA Copernicus programme. Measurements at 50 sites for over 18 months were used to calibrate and validate results from satellite data. With limited recorded groundwater flood data in Ireland, the use of remote sensing data provides historical archives of images to look at past flood conditions to optimise the detection of groundwater and delineate maximum groundwater flood maps. These new data improve the fundamental hydrological understanding of groundwater flooding in Ireland, enabling key stakeholders to develop appropriate flood mitigation measures and allow for informed flood assessments to be made in future.

Investigating the Significance of Groundwater Pathways in Radon Transportation

L. Collins1 (Lawrence.Collins@DCCAE.gov.ie), V. Gallagher1, M. Glennon1, J. Hodgson1, and K. Tedd2

1 Geological Survey Ireland, Tellus

2 Geological Survey Ireland, Groundwater

Radon is a naturally occurring radioactive gas formed by radioactive decay of uranium. Radon can accumulate in dwellings and workplaces, and prolonged exposure through inhalation can cause lung cancer in humans. Ireland has one of the highest average rates of radon gas exposure in Europe. Naturally radiogenic rocks are known sources of radon; however, the relationship between mapped bedrock geology and surface expression of radon occurrence can be complex. EPA mapping of indoor radon concentrations has highlighted areas prone to high levels of radon overlying bedrock with relatively low uranium levels, most notably Carboniferous limestone (Fennell et al. 2002). Modelling of radon-prone areas in Ireland (Elio et al. 2017) has suggested that the high indoor radon concentrations observed over limestone bedrock reflect the presence of karst aquifers that may be acting as conduits for radon dissolved in groundwater. To assess the potential for groundwater to transport radon, Geological Survey Ireland is now sampling group water schemes in geological settings with different aquifer properties. A number of settings have been sampled to date and initial findings indicate that groundwater sourced from the Leinster granite has high radon concentrations between 300-700 Bq/L. Diffuse karst systems around Kilkenny have significantly lower concentrations between 10-20 Bq/L, and conduit karst systems north of Galway have slightly higher concentrations between 20-60 Bq/L. Further work will involve increasing the sample size and consideration of the role of aquifer properties in the transportation of radon, particularly in karst systems where degassing or dissolution of radon may be occurring.

Potential of machine learning in linking national airborne radiometric data to soil class mapping*

D. O’Leary1 (d.oleary1@nuigalway.ie), P. Touhy2, P. Mellender3, O. Fenton3, E. Daly1, C. Brown1

1 Earth and Ocean Science, Ryan Institute GIS centre, School of Natural Sciences, National University of Ireland Galway, Co. Galway.

2 Teagasc, AGRIC, Moorepark, Fermoy, Co. Cork.

3 Teagasc, Johnstown Castle, Co. Wexford.

Accurate maps of soil types at the field scale are required for many environmental and planning applications, from land use management and precision agriculture to drainage schemes and infrastructure development.

The thematic mapping of soil traditionally has been done using in-situ point sample measurements by a core or auger system. The operator then follows a standardised classification system to place the sample into groups defined by the national soil classification system. This method is slow, costly and subjective depending on the experience of the operator. It is difficult to create maps from point classifications as boundary conditions are rarely sampled.

More recently, the Irish Soil Information System (Irish SIS) used environmental co-variates (temperature, climate, elevation, slope etc) alongside auger data and historical soil maps to create a national soil map to a scale of 1:250,000. This however lacks the resolution at field scale and provide only a probability of any one soil group being present at any point location.

Geophysics has the potential to bridge this scale gap. The Geological Survey of Ireland is currently flying a national airborne geophysical survey, known as Tellus and this work highlights a preliminary investigation of using the radiometric data alongside digital elevation model (DEM) data and high resolution Teagasc soil maps, as input to machine learning classification techniques to map soil within the Great Group classification of the Irish SIS.

Future work will include ground truthing of the results using a recently funded CMD Mini-Explorer ground conductivity meter on sites across Ireland.

Insights into the basin evolution and structural framework of the Carboniferous of South-Central and SE Ireland

K. Torremans1 (koen.torremans@ucd.ie), J. Güven1, R. Doyle1, J. Conneally1, N. Vafeas1, E. Dunlevy1, J.J. Walsh1

1 Irish Centre for Research in Applied Geosciences, School of Earth Sciences, University College Dublin, Belfield, Dublin 4.

Understanding subsurface resources in sedimentary basins is critically dependent on a solid interpretation of the basin history and the existence of high-quality models. In this presentation we will show insights into the basin evolution and the structural framework of the Carboniferous of South-Central and South-East Ireland. Our analysis was done using a multidisciplinary workflow, combining several state-of-the-art geomodelling and spatial analysis systems. Large datasets combine geological, micro-palaeontological, reflection seismic, drillhole and potential field geophysical data at a variety of scales from both open source and proprietary information. This includes recent Tellus data in South-Central Ireland and seismic reflection data over the Castlecomer coalfield.

We have characterized the evolution of major Carboniferous fault networks in the study area and mapped out regional thickness and facies changes. Using this data, we will consider how these fault networks and the wider palaeogeographic context have controlled regional facies variability. We will also show how the basin architecture relates to the regional and local scale distribution of diagenetic and hydrothermal alteration in the carbonates. Variscan tectonic deformation has affected the Carboniferous strata and we will illustrate how this is expressed and what effect this had on current depth-to-targets in regional models. We will discuss strategies and workflows on how to represent the regional lateral facies variations in subsurface models, as evident for example in the Lower Limestone Shales, Pale Beds and Shaley Pales in the South-Central Midlands.

Testing the impact of fault growth models on syn-rift stratigraphy using forward stratigraphic modelling*

E. O’ Donnell1,2 (eoin.o-donnell.1@ucdconnect.ie), P.D.W. Haughton1,2, L. Amy1,2, C. Childs1,3, C. Griffiths 4

1 iCRAG – Irish Centre for Research in Applied Geoscience, University College Dublin

2 UCD School of Earth Sciences, University College Dublin

3 Fault Analysis Group, University College Dublin

4 Curtin University, Perth, Australia

Numerical modelling can contribute to increased understanding of the complex interaction between tectonics and drainage patterns, sediment entry points and depocentre locations in rift basins. This study employs forward stratigraphic modelling to investigate how details of fault system evolution and intrabasinal relay development can impact hanging wall sediment accumulation and stratigraphy. It has been carried out using Sedsim (Stratamod) which uses a hydrodynamic approach to model sediment dispersal.

Two contrasting models exist for the development of faults by growth and linkage of fault segments. In the Isolated Model, segments of a fault array initiate as a series of isolated faults that grow by an increase in maximum displacement and length until interacting to form relay zones. The Constant Length Model recognises that fault length is established rapidly, relay zones form under low strains and subsequent fault growth is achieved by an increase in fault displacement with minimal change in fault length.

In the Isolated Model relays are seen to act as major sediment conduits prior to breaching and feed local, poorly connected hanging-wall depocentres with coarse material concentrated at the base of the relay ramps. The early history of the Constant Length Model involves sediment routing via relay ramps until the integrated uplift across all the fault segments diverts flow around the fault tip at one end of the fault array. Deposition is then focussed as an aggradational axial fan with coarse material closest to the fault tip and finer grained material concentrated at the base of the relay ramps.

The implication is the fault growth model, and extent to which earlier structures are reactivated, can have an important impact on the early syn-rift stratigraphy.

Regional chemostratigraphic correlation of Irish Carboniferous volcanic ash horizons – an integrated approach*

Hilde A. Koch1,2 (hkoch@tcd.ie), David Chew1,2, Michael Philcox1,2, Balz S. Kamber3

1 School of Natural Sciences, Trinity College Dublin, Ireland

2 iCRAG, School of Natural Sciences, Trinity College Dublin, Ireland

3 School of Earth, Environmental and Biological Sciences, Queensland University of Technology, Brisbane, Australia

Most of the ore deposits in the Irish Pb-Zn Orefield are restricted to two stratigraphic units: the deeper water Waulsortian Limestone Formation in southern and central Ireland and the shallow marine Navan Group of north central Ireland. Both formations were deposited during a northward directed marine transgression in the Tournaisian (Philcox, 1984). Research on the origin and geological context of these deposits requires accurate stratigraphical correlations within the host rocks. Volcanic ash layers within the Tournaisian and early Viséan provide possibilities of high resolution correlation to supplement the relatively coarse resolution established using biostratigraphy for these rocks.

This study introduces a multi-proxy approach to correlate these volcanic ash horizons using high-precision trace element bulk-rock geochemistry, U-Pb zircon geochemistry, as well as apatite characterisation (trace element and U-Pb analyses) to provide a chemostratigraphic framework.

Three different tuff horizons from the Slieve Dart area have been confidently distinguished and correlated using all of the above mentioned methods. 11 out of 16 tuffs from the host rocks of the Lisheen deposit revealed the same geochemical signature using REE diagrams, biplots and a modified best match comparison method (Marx et al., 2005). There is also a specific, more variable pattern for the Navan tuffs, which could not be cross-correlated with other tuffs. U-Pb zircon ages from six different Lisheen samples, taken from six drillcores, yield ages between 344±2 Ma and 349±3 Ma, whereas no zircons were found within the Navan tuffs.

Large Igneous Province volcanism and carbon release as cause for Early Jurassic Global Change Events

M. Ruhl1,2 (micha.ruhl@tcd.ie), S.P. Hesselbo3, H.C. Jenkyns4, W. Xu2,5, A. Al-Suwaidi6, R.L. Silva1,2

1 Department of Geology, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland

2 Irish Centre for Research in Applied Geosciences (iCRAG), Trinity College Dublin, The University of Dublin, Dublin 2, Ireland

3 Camborne School of Mines and Environment and Sustainability Institute, University of Exeter, Penryn TR10 9FE, UK

4 Department of Earth Sciences, University of Oxford, Oxford OX1 3AN, UK

5 Department of Botany, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland

6 Department of Earth Sciences, Khalifa University, Abu Dhabi, United Arab Emirates

Earth history is marked by major Global Change Events, often linked to carbon greenhouse gas release and associated carbon-cycle perturbations. Some of the largest global change events occurred in the Early Jurassic, and are known as the Triassic–Jurassic mass extinction (at ~201 Ma) and the Toarcian Oceanic Anoxic Event (T-OAE; at ~183 Ma). Both events appear temporally linked to emplacement of the Central Atlantic Magmatic Province (CAMP) and Karoo-Ferrar Large Igneous Province, respectively, but causality is poorly constrained.

Here, we present new data linking the Early Jurassic Global Change Events to major volcanic activity and associated carbon release at those times. We discuss how enhanced atmospheric pCO2 may link to changes in seawater temperature and coeval climatic/ environmental change, and its role in the mass extinction of species, and deterioration of ecosystems on land and in the oceans.

We will elaborate on the lessons that past global change events may hold for our understanding of (changes in) feedback mechanisms and tipping-points in the contemporary Earth system, especially in response to anthropogenic carbon release.

Csővár revisited: new geochemical data to the integrated stratigraphy of a Triassic-Jurassic boundary section in the western Tethys*

E. B. Kovács1,2,3 (kovacsemmablanka@gmail.com), M. Ruhl1, A. Demény4 and J. Pálfy2,5

1 Department of Geology, Trinity College Dublin, Dublin 2, Ireland

2 Department of Geology, Eötvös Loránd University, Budapest, Hungary

3 Institute for Nuclear Research, Hungarian Academy of Sciences, Debrecen, Hungary

4 Institute for Geochemical Research, Hungarian Academy of Sciences, Budapest, Hungary

5 MTA-MTM-ELTE Research Group for Paleontology, Hungary

One of the canonical Big Five mass extinctions and major environmental changes occurred at the end of the Triassic. Here we combine integrated stratigraphic analyses with the application of geochemical proxies at improved resolution to gain new insights into the timing, driving forces and mechanism of this event. The Csővár-section (Hungary), which was deposited in an intraplatform sedimentary basin, presents one of the few continuous and reasonably fossiliferous marine sedimentary records across the Triassic-Jurassic boundary. Previous studies were among the first to recognize a major negative carbon isotope anomaly near the system boundary (Pálfy et al., 2001). The system boundary is defined by conodont, radiolarian, foraminifera and ammonoid biostratigraphy (Pálfy et al., 2007). Carbon isotope chemostratigraphy offers the best potential for global correlation (Korte et al., 2019), but as not all of the anomalies reported from other sections appear at Csővár, we have developed an improved inorganic carbon isotope curve from the section, on the basis of higher resolution sampling over an extended stratigraphic interval. In addition, we also investigated changes in Hg as this emerging geochemical proxy has been demonstrated to be useful to track coeval volcanism (Percival et al., 2017). The Central Atlantic Magmatic Province (CAMP) is generally assumed to have a role in the end-Triassic global change and mass extinction, and our new carbon isotope and Hg concentration curves from Csővár reveal further details to the link between CAMP volcanism, carbon cycle perturbation and biotic turnover across the Triassic-Jurassic boundary.

The History of Life project: student film-making as a tool for enhanced learning

J. Murray1,2 (john.murray@nuigalway.ie), T. Henry1,2, L. Ní Dhonnchadha3, B. McSharry3, G. McGrath3, I. Mac Labhrainn3 and S. Flynn3,4

1 Earth & Ocean Sciences, School of Natural Sciences, National University of Ireland Galway, University Road, Galway, Ireland

2 Irish Centre for Research in Applied Geosciences (iCRAG)

3 Centre for Excellence in Learning and Teaching (CELT), Arts Millennium Building, National University of Ireland Galway, Ireland

4 Irish Universities Association, 48 Merrion Square, Dublin, Ireland

The strong temporal narrative which underpins geology and palaeontology makes them well suited for film. Since 2011, NUI Galway final-year undergraduate science students taking the module History of Life have been tasked with researching a significant theme related to the evolution of life on Earth, and then producing a short documentary-style film on their chosen topic. The students work in small teams and have no prior training in film-making. Their finished films are uploaded to a specially created channel on YouTube, where they have experienced high viewing figures. The value of this teaching approach is that it engages all of the major learning domains. Cognitive skills are enhanced through acquisition, analysis and communication of knowledge, and practical skills are honed through the deployment and use of technology. The students develop team-working skills and they find the learning experience to be really enjoyable and novel: positively impacting on the affective domain. Student feedback has generally been extremely positive: they recognise that in essence it is an exercise in science communication. In the ten years this teaching initiative has been running, many inspiring moments have been captured on film by the various History of Life student teams. The intention of this presentation is to showcase some highlights of this work.

Spatial and Temporal Variations in the Geochemistry of the River Shannon

A.E. Carey1 (carey.145@osu.edu), S.A. Welch1, C.B. Gardner1, D.F. Smith1, P. Croot2, T. Henry2, and W.B. Lyons1

1 School of Earth Sciences, The Ohio State University, Columbus OH USA

2 Department of Earth and Ocean Sciences, National University of Ireland Galway

The River Shannon is the largest river in Ireland with a catchment area of 15,353 km2 and a mean annual discharge of ~210 m3/s. We have sampled the length of the river 4 times. Our sampling campaigns occurred in March, June, and August, 2018, and in October 2019 at 10 locations from the river’s origin at Shannon Pot to just below Lough Derg at Ballina. The samplings included ones conducted during a very cool and wet winter to early spring in 2018 and during a very warm and dry late spring to summer period in 2018, and during a typical autumn in October 2019. In general the spatial variations in geochemistry reflect the changes in lithologies of the sub-catchments and inputs from the tributaries draining these sub-catchments, especially from the Rivers Inny and Suck. For example, dissolved Ca increases downstream reflecting the dominance of limestone weathering as the river flows through the midlands region. Higher concentrations of dissolved SO4 in the upper reaches from Shannon Pot to Dowra probably reflect the weathering of shales and the dissolution of evaporites there. The dissolved NO3 also increases downstream suggesting input from agricultural activities. Interestingly, the Ca:Si molar ratio and other constituents remain relatively constant at Ballina, suggesting the importance of mixing of the tributary inputs, especially in the lower loughs along the river. These data will also be discussed in terms of the fluxes of biogeochemical important constituents to the Shannon estuary.

Provenance of Mesozoic sediments in the North Celtic Sea and Saint Georges Channel Basins: Results from Detrital Zircon and Apatite studies*

Odhrán McCarthy(1,2) (odhran.mccarthy@ucc.ie), Patrick Meere(1,2), David Chew (2,3), Brenton Fairey(4)

1 School of Biological, Environmental and Earth Sciences, University College Cork

2 Irish Centre for Research in Applied Geology, O’Brien Centre for Science, University College Dublin

3 Department of Geology, Trinity College Dublin

4 Chemostrat, Welshpool, United Kingdom

The provenance of the sediments comprising the Mesozoic infill of the North Celtic Sea and Saint Georges Channel basin has a complex history which lacks distinctive characteristic source signals. This is compounded by an abundance of available sources, the recycling and mixing of sediment and a complex structural history of the basins. This study reveals the first direct source indicators for sediment routing from each basin with direct linkage of Zircon profiles from palaeocontinents during the Jurassic. New Apatite data questions the interpreted age of sedimentation for the greensand formation in the NCSB and heavy minerals studies provide an insight to the paleoenvironmental control on sediment transport and basin connectivity. It is evident that a mutli-proxy approach is required when interpreting offshore sediment routing and this study aims to provide some insight to long standing questions surrounding these basins.

Temporal Variability of Cold-water Coral Habitats from the Porcupine Bank Canyon NE Atlantic: Preliminary Results*

L. O’Reilly1,2 (luke.oreilly@ucc.ie), A. Lim1,2, J. Titschack3,4, O.J. O’Connor5,6, J. Appah1, K. Harris1, L. Macedo1, R. Strachan1 and A. Wheeler1,2,7

1 School of Biological, Earth and Environmental Science, University College Cork, Ireland.

2 Environmental Research Institute, Cork, Ireland.

3 MARUM – Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.

4 SaM, Senckenberg am Meer, Abteilung Meeresforschung, Wilhelmshaven, Germany.

5 Department of Radiology, Cork University Hospital (CUH), Wilton, Cork, Ireland.

6 Department of Radiology, University College Cork (UCC).

7 iCRAG (Irish Centre for Research in Applied Geosciences).

Cold-water corals (CWCs) trap current-suspended particles from their environment, which become deposited in and around the coral framework. This results in the growth of topographic features called CWC mounds, which contain a record of paleoenvironmental change through time. This presentation serves as a preliminary update on a project within the MMMonkey_Pro (www.marinegeology.ucc.ie) research programme, which focuses on the temporal development and paleoenvironmental history of CWC habitats in submarine canyons.

ROV-mounted vibrocore samples have been retrieved from a range of CWC habitat types within the Porcupine Bank Canyon (PBC), NE Atlantic. These cores have been scanned using computed-tomography (CT), creating comprehensive imagery of the internal architecture of the CWCs, as representative of reef development stages. The extrapolated data is processed using Amira software and coral core-specific algorithms (see Titschack et al. 2015), allowing CT-derived facies types to be defined. An off-mound core has revealed a fine-scale record of ice-rafted debris (IRD). The cores have been further logged and subsampled for high-resolution laser granulometry and composition (CaCO3% and Organic%). A geochronological framework has been constructed, by subjecting planktonic and benthic foraminifera to 14C AMS radiometric dating. In 2020, this study will use other foraminiferal related proxies to constrain glacial/interglacial periods and reconstruct paleoenvironmental conditions.

This unique multidisciplinary ensemble approach, will give insight into regional environmental conditions, uncovering the controls on mound cessation and development related to the dual energy, CT-identified reef development stages. For the first time, we intend to ascertain what controls the formation of different CWC habitats in the PBC.

An Investigation of the impacts of Termination 5 on Thermohaline Circulation in the Eastern North Atlantic*

M.J. Curran1 (m.currran18@nuigalway.ie), A. Morley1,2

1 School of Geography and Archaeology and The Ryan Institute at the National University of Ireland, Galway University Road, Galway H91 REW4, Ireland.

2 iCRAG – Irish Centre for Research in Applied Geosciences.

The Atlantic Thermohaline Circulation is an important component of the earth’s climate system. Recent studies have shown that variations in Nordic Seas Deepwater circulation precede abrupt climate changes in the North Atlantic Region. This is crucial as multiple climate models highlight that enhanced melting of the Greenland Ice Sheet due to future warming may have a destabilising effect on Nordic Seas Deepwater, a central component of North Atlantic Deepwater formation and thus Thermohaline Circulation. However, our understanding of how the climate system reacts to large freshwater input is lacking.

Here we investigate the transitional period Termination 5 (T5) from a cold, glacial period, Marine Isotope Stage (MIS) 12 (~430 ka) to a warm, interglacial period, MIS 11 (~424 ka) to assess the response of Nordic Seas Deepwater formation to the melting of the Greenland Ice Sheet.

Using sediment core DSDP-610B, located ~700 km west of Ireland, we reconstruct the evolution of Nordic Seas Deepwater by means of grainsize analysis. Further, a combination of planktonic foraminiferal assemblage counts and ice-rafted debris (IRD) counts allow us to reconstruct surface water properties: temperature and the movement of oceanic fronts across the Eastern North Atlantic during T5. Overall, this strategy enables a palaeoceanographic analysis of the oceanic response to the addition of large freshwater fluxes into the North Atlantic during T5. This research will increase our understanding of the climate system, which is the best way to improve our effectiveness in tackling climate change and reduce our vulnerability.

Seismic signature of the North Atlantic climate fluctuations

F. Le Pape1,2 (flepape@cp.dias.ie) and C. J. Bean1,2

1Dublin Institute for Advanced Studies (DIAS), Dublin, Ireland

2iCRAG centre, University College Dublin, Belfield, Dublin 4, Ireland

Seismic vibrations generated in the ocean from ocean waves interactions represent the strongest ambient seismic noise level recorded on land. However, the recorded noise energy will still vary with seasons due to changes in storm activity. Here, seismic data recorded on land but also at the seafloor have been processed to investigate the seasonal variations of the seismic ambient noise wavefield. Ocean wave directional spectrum data derived from ocean wave model hindcasts suggest those variations are correlated with changing patterns in ocean waves interactions and therefore changes in source locations. Compared to land stations, the seismic wavefield recorded at the seafloor, and in particular changes in the excitation of seismic modes due to site effects, can help characterize the ocean seismic source locations that fluctuate through the seasons. In order to understand those observations in detail, we use 3D numerical simulations to show how the subsurface structure below the seafloor but also the water column will affect the recorded wavefield for different stations and sources locations.

Global Megadrought? Perspective on the size and extent of the 4.2kyr event, and its impact on the Harappan civilization, from stalagmite geochemistry around the Indian Ocean

N. Scroxton1,2 (nick.scroxton@ucd.ie), S.J. Burns2 D. McGee3, L.R. Godfrey4, L. Ranivoharimanana5, P. Faina5

1 UCD School of Earth Sciences, University College Dublin, Belfield, Dublin 4, Ireland.

2 Department of Geosciences, 611 North Pleasant Street, University of Massachusetts, Amherst, MA 01003, USA.

3 Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge MA 02139, USA

4 Department of Anthropology, 240 Hicks Way, University of Massachusetts, Amherst, MA 01003, USA

5 Mention Bassins sédimentaires, Evolution, Conservation (BEC) - BP 906 – Faculté des Sciences – Université d’Antananarivo - 101 Antananarivo, Madagascar

The 4.2 kyr event is regarded as one of the major climatic perturbations of the Holocene and has been linked to societal change and collapse in the Akkaddian, Eqyptian and Harappan civilizations. Well characterized climatic changes centered on the Mediterranean and Middle East indicate a regional drought lasting for 300 years. This has led to the event being dubbed a “Global Megadrought” and the 4.2 kyr event now forms the most recent GSSP golden spike, dividing the middle and late Holocene. However, beyond this data-rich heartland, is the 4.2 kyr event really a climatic event of global significance?

In this study we investigate the impact of 4.2 kyr event on circum-Indian Ocean hydroclimate and whether it played a role in societal change in the Harappan civilization in the Indus valley around 3.9 kyr BP. We use twelve high-resolution paleo-hydroclimate records including eight stalagmites and four sediment cores. Principal Component Analysis of these twelve records indicates a major basin wide drying between 4.1 and 3.5 kyr BP. This event is not the 4.2 kyr event but may be frequently labelled as such by low-resolution records in the paleoclimate literature. The 4.2 kyr event is visible in the second principal component and in some locations is significant. However, there is little regional coherency, and is typically not of unusual magnitude. Region wide gradual drying between 4.1 and 3.5 kyr BP is more consistent with archaeological evidence of the end of the Harappan civilization than an abrupt event at 4.2 kyr BP.

Origin of rare eclogite clasts in a chondritic meteorite

I. Sanders1 (isanders@tcd.ie)

1 Department of Geology, Trinity College Dublin.

Chondritic meteorites (chondrites) are fragments of cosmic ‘greywacke-like’ rock that once constituted baby planets (planetesimals) which accreted from the disk of dispersed material around the infant Sun between 4565 and 4562 Myr ago as the planets were being assembled. They consist of chondrules (igneous textured spherules) in fine-grained matrix, with rare mm-scale chips of rock.

In one enigmatic chondrite belonging to the so-called CR class, several chips of eclogite uniquely occur. The eclogite equilibrated at ~30kbar and 1000°C (Kimura et al. 2013, Am Min 98, 387) i.e. deep in the interior of an unusually large (Moon-sized) body. That body broke up (presumably due to a collision with another large body) and clasts of it became mixed with the chondrules and matrix that comprised the ~4562 Myr-old CR planetesimal.

The eclogite has a fine-grained (~20 microns) equilibrated texture. Why, at 1000°C, is it not coarse-grained? Its texture is suggestive of hornfels, a rock formed during brief, metamorphic heating. Perhaps the protolith was basalt-like crust that foundered and sank quickly to a great depth in the Moon-sized body (whose interior was fully molten due to 26Al heating) before a giant impact burst it asunder.

And why are clasts of eclogite so extremely rare in chondrites? This may be because giant impacts between Moon-sized bodies date from after about 4562 Myr ago (5 Myr after the beginning) when a change in Jupiter’s orbit launched many bodies on collision courses, and because CR chondrites accreted late enough to capture some of the collision debris.

A novel multi-shot laser ablation protocol: minimising sampling volume and LIEF*

E. Corbett1,2 (corbetep@tcd.ie), A. Simonetti2, P. Shaw3, L. Corcoran2, Q. Crowley1, B. Hoare1

1 Department of Geology, Trinity College Dublin, Dublin 2, Ireland.

2 Department of Civil and Environmental Engineering and Earth Sciences (CEEES), University of Notre Dame, IN 46556, USA.

3 Nu Instruments Ametek, Wrexham LL13 9XS, Wales, UK.

The interaction of incident laser radiation and sample substrate is complex and difficult to predict. Natural zircons are often both structurally and chemically heterogeneous in 3-dimensional space. Encountering growth-related, structural micro-heterogeneities, inclusions and chemical complexities is almost inevitable when employing ‘conventional’ static, high-frequency laser sampling protocols often lasting several tens of seconds at a time.

A multi-shot approach to laser ablation by contrast reduces sample exposure time to incident laser radiation by applying multiple 1 Hz shots in delayed succession to a single sampling site. This process can be conceptualised as a “slowing down” of a high-frequency (10-20 Hz) static Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analysis. Each laser pulse to strike the sample, produces signal peak which is distinct albeit transient. The ability to integrate and collate signal pulses for a small number of consecutive laser shots (10-30 shots), as opposed to continuously pulsing the laser, produces precise age determinations (<1% reproducibility, 2σ level) on small sample volumes (~695µm3 on 91500 zircon standard). The multi-shot LA-ICP-MS protocol employed here effectively eliminates ‘downhole’ fractionation as the resultant craters are extremely shallow (as shallow as ~553nm on 91500 zircon standard) and maintain an aspect ratio of <<1. Further benefits include a reduced probability of thermally induced effects (e.g., substrate melting), plasma loading, and the potential for signal mixing (with depth) in a heterogeneous sample.

Sr isotopes indicate very rapid (~103 yr) formation of metal-rich layers by reactive melt percolation in an open-system layered intrusion

J. Stephen Daly1 (stephen.daly@ucd.ie), Luke N. Hepworth2, Brian O’Driscoll3, Chris G. Johnson3, Ralf Gertisser2 and C. Henry Emeleus4†

1 UCD School of Earth Sciences, University College Dublin, Belfield, Dublin 4, Ireland.

2 School of Geography, Geology and the Environment, Keele University, Keele, United Kingdom

3 School of Earth and Environmental Sciences, University of Manchester, Manchester, United Kingdom

4 Department of Earth Sciences, Durham University, Durham, United Kingdom; †Deceased

In order to test whether the crystal mushes that form layered mafic intrusions can behave as open systems, we have investigated mineral-scale textural, chemical and Sr isotopic heterogeneity in the c. 60 Ma Rum intrusion, Scotland. Within Unit 10 of the Rum intrusion, intercumulus plagioclase and clinopyroxene crystals in peridotite 1-2 cm above and below millimetric Cr-spinel seams exhibit complex optical and chemical zoning (Hepworth et al., 2017). These Cr-spinel seams are closely associated with sulphide and platinum-group element (PGE) mineralization. High precision Sr isotopic analyses of individual intracrystal zones in intercumulus plagioclase and clinopyroxene from the PGE-enriched Cr-spinel seams reveal significant intra-crystalline heterogeneity. 87Sr/86Sr differences exist between plagioclase crystals, between clinopyroxene and plagioclase, and within plagioclase. Preservation of Sr isotope heterogeneities at 10-100 µm length-scales implies cooling of the melts that formed the precious metal-rich layers at rates >1 °C per year, and cooling to diffusive closure within 103 years. Combined textural observations and intra-crystal 87Sr/86Sr data also highlight the importance of repeated cycles of dissolution and recrystallization within the crystal mush, and together with recent documentation of ‘out-of-sequence’ layers in other layered intrusions (Mungall et al., 2016; Wall et al., 2018), raise the prospect that basaltic magmatic systems may undergo repeated self-intrusion during solidification.

Regional assessment of groundwater resources in the greater Dublin area

N. Duncan1 (natalie.duncan@gsi.ie), K. Tedd1, S. Carey1, D. Doherty2, J. Greene2, C. Kelly2, M. Lee1, R. Meehan3, A. Pilmer4 and S. Raymond1

1 Geological Survey Ireland, Ballsbridge, Dublin 4.

2 Tobin Consulting Engineers, Blanchardstown, Dublin 15

3Talamh Ireland, Navan, Co. Meath

4 Gavin & Doherty Geosolutions, Rathfarnham, Dublin 14

Geological Survey Ireland (GSI) is carrying out a regional assessment of potential groundwater resources for the greater Dublin area. The project is a response to the growing need for additional drinking water supplies in that region and has been developed in consultation with a number of stakeholders. The project will run for an initial phase of 3 years, focusing on the east and south east of the country. A systematic, catchment based approach is being applied for this assessment, with the overall aim of identifying zones with good potential for groundwater resources. The project will be evaluated at the end of the 3 years to determine if it should be rolled out to national coverage.

The assessment includes the areas of 32 surface water catchments. Each catchment is assessed separately, and comparatively, and will result in a series of groundwater resource reports. The purpose of these reports is to (a) compile all relevant, readily available hydrogeological information for the proposed catchments; (b) develop an initial hydrogeological conceptual model for the catchments; (c) provide a basis for prioritising further investigation into groundwater resources therein; (d) identify existing information which was not available for the report but which would be useful for further analysis; and (e) identify information gaps which could be addressed by GSI or other parties.

To date, eight catchments have been assessed: the Boyne, Barrow, Broadmeadow, Delvin, Loughlinstown, Mayne-Santry, Nanny and Tolka. The results of selected assessments are discussed here.

Separating diffractions pre- and post-migration with deep learning*

B. Lowney1, 2 (brydon.lowney@ucdconnect.ie), I. Lokmer1, 2, G.S. O’Brien3, C.J. Bean4

1 UCD School of Geological Sciences, University College Dublin, Belfield, Dublin 4.

2 Irish Centre for Research in Applied Geoscience, University College Dublin, Belfield, Dublin 4.

3 Tullow Oil Ltd, Central Park 1, Carmanhall, Dublin 18.

4 School of Cosmic Physics, Dublin Institute for Advanced Studies, 5 Merrion Square, Dublin 2.

Diffractions have many uses in geophysics, including velocity analysis, wavefront tomography, and structural imaging. To utilise diffractions, they must first be separated from the seismic wavefield. Removing diffractions is challenging due to their low amplitudes and the blending of diffraction and reflection energy. Analytical methods to separate diffractions exist for both pre- and post-migration, however, are computationally expensive and require parameterisation, which is time-consuming, requires manual intervention, and difficult to optimise. Here, we outline deep learning methods for classification and separation of diffraction energy for both pre- and post-migration.

Pre-migration diffraction separation techniques revolve around the fact diffractions are hyperbolic while reflections are planar in pre-migrated data. By calculating the slope reflection energy and removing energy which conforms to this slope, a volume remains which contains only diffractions and noise, a method called plane-wave destruction. However, noise diminishes the final image, especially where diffractions and noise are comparable amplitudes. Here, a Generative Adversarial Network is created which can replicate the separated diffractions directly from pre-migrated data, removing the need for analytical separation.

Post-migration diffraction separation utilises the dip-angle gather domain to remove diffractions. In this domain, diffractions appear linear while reflections are concave. Here, diffractions have been separated using apex destruction and tau-p filtering to remove non-linear energy. A neural network is trained using these images, allowing diffraction images to be created directly from stacked images. While this is beneficial, any bias introduced from filtering, such as the remnant steep reflection energy, is also introduced to the neural network.

The emerging field of Agri-Geophysics – A future in Ireland?

E. Daly1 (eve.daly@nuigalway.ie), C. Brown1, P. Touhy2, P. Mellender3, O. Fenton3

1 Earth and Ocean Science, Ryan Institute, School of Natural Sciences, National University of Ireland Galway, Co. Galway.

2 Teagasc, AGRIC, Moorepark, Fermoy, Co. Cork.

3 Teagasc, Johnstown Castle, Co. Wexford.

Soil is a vital non-renewable resource with the capacity to deliver food production, nutrient retention and cycling, carbon storage, filtration of water and a habitat for biodiversity. Global food demand is expected to increase by 100% by 2050, and the Government’s response (Food Wise 2025) is for agricultural intensification to satisfy domestic demand and increase exports, possibly at the expense of water quality and greenhouse gas emission targets (UN Sustainable Development Goals), and the objectives of the Common Agricultural Policy which insists sustainable increases in production.

Increasingly, geophysics is used to provide a multidimensional suite of tools to image the subsurface (depth <2-5m), and monitor fluid dynamics and biogeochemical processes. The emerging research field of Agri-Geophysics and the availability of high spatial and temporal resolution Earth Observation data products is helping to 1) fill the scale gap from in-situ field measurements to landscape scale mapping, and 2) in characterization of soil structure directly (via impact of soil porosity, and mechanical properties on geophysical signals) or indirectly by measurement of proxy variables (wetness and rates of drainage).

Ongoing research in Ireland includes integrating Tellus Airborne Geophysical datasets with Satellite optical data products via data analytic techniques to improve soil characterisation and identification of soil drainage status. Future work may include monitoring Soil Moisture content and Root Zone Water Dynamics leading to an improved understanding of the underlying processes and interactions in the soil-plant-atmosphere continuum of our agri-ecosystems.

Testing a Negative Carbon Emissions Technology via enhanced plant mediated chemical weathering

W. Xu1,2,* (weimu.xu@tcd.ie), C. Yiotis1,2,*, B.S. Kamber3, L.W. Gill2,4, J. Knappe4, T. Riegler2,5, J.C. McElwain1,2

1 School of Natural Science, Discipline of Botany, Trinity College Dublin, College Green, Dublin 2, Ireland.

2 Irish Centre for Research in Applied Geosciences (iCRAG).

3 Geology and Geochemistry, Queensland University of Technology, Australia

4 School of Engineering, Trinity College Dublin, College Green, Dublin 2, Ireland

5 School of Natural Sciences, Discipline of Geology, Trinity College Dublin, College Green, Dublin 2, Ireland

The recent Intergovernmental Panel on Climate Change (IPCC) 1.5°C Special Report suggests that CO2 removal is required to achieve net zero emissions in the 21st century in order to limit the temperature rise below 1.5°C, in all future pathways. Plant mediated enhanced chemical weathering offers one theoretical solution by increasing the rate at which photosynthetically assimilated CO2 helps to weather calcium/magnesium silicate rocks, which in turn increase the rate at which carbonates are deposited and stored in the ocean system. Our iCRAG funded projects experimentally explore the potential for enhanced carbon sequestration as a result of volcanic ash fertilization of Irish grasslands under modern and future climatic conditions.

Towards these aims, experiments have been carried out in controlled environment growth chambers simulating current and future climatic conditions over a period of 4 months. A total of 8 treatments and a split-plot experimental design have been used to test the potential for grass-mediated enhanced weathering of volcanic ash-fertilised soil. Preliminary results on the degree of volcanic ash weathering and the effects of ash fertilisation on grass morphology, physiology and productivity as well as on water cycling will be presented. Our study will assess the potential of volcanic ash addition to Irish soils as a “negative” emissions technology and will optimise a protocol for future field-based trials.

Using Compositional Data Analysis (CoDA) to characterise groundwater geochemistry in the vicinity of Lisheen Mine, County Tipperary, Ireland*

S. Wheeler1,2 (sean.wheeler@nuigalway.ie), T. Henry1,2, J. Murray1,2, L. Morrison1,2 and Frank McDermott3,2

1 Earth and Ocean Sciences, National University of Ireland Galway, University Road, Galway, Ireland

2 Irish Centre for Research in Applied Geosciences (iCRAG)

3 UCD School of Geological Sciences, University College Dublin, Belfield, Dublin 4

Lisheen Mine ceased underground extraction of lead/zinc ore at the end of 2015, after 16 years of operation. The target ore deposit was hosted within Carboniferous (Tournaisian) limestones at a depth of between 150 and 200 metres. Eight groundwater wells (six regional and two onsite compliance) were sampled regularly post-closure as part of the Lisheen Mine Closure, Restoration and Aftercare Management Plan. Groundwater geochemistry data from these eight wells has been statistically investigated using Compositional Data Analysis (CoDA). The CoDA method of using log-ratios when comparing compositional data was originally developed by John Aitchison in the 1980’s as a way of mitigating against the effects of spurious correlation first recognised by Karl Pearson. The Principal Component Analysis (PCA) of centre log-ratio transformed compositional groundwater data from Lisheen permits the geochemical characterisation of the eight sample sites, despite their relative regional geographic proximity and apparent similarity in host rock properties. Elevated sulphate concentrations are more likely to be observed in wells located more proximal to the mine workings. Some wells are better characterised by elements and compounds associated with land-use practices (e.g. nitrate and potassium from fertiliser).

This study from Lisheen clearly demonstrates the usefulness of CoDA as a method of chemically differentiating between broadly similar groundwaters and it illustrates its capacity to assist in elucidating the reasons underpinning these differences. The same approach could also be applied to a variety of scenarios where chemistry data has been obtained (including environmental monitoring, mineral exploration and land management).

Uranium in groundwaters from the Leinster Granite, SE Ireland*

Fani Papageorgiou1,2 (fani.papageorgiou@ucdconnect.ie) and Frank McDermott1,2

1UCD School of Earth Sciences, University College Dublin, Belfield, Dublin 4.

2iCRAG (Irish Centre for Research in Applied Geosciences), University College Dublin, Belfield, Dublin 4.

Long-term exposure to drinking water with elevated uranium concentrations (≥30 μg/l) leads to kidney-related disease (nephritis) as a result of its chemical toxicity (WHO, 2011). Our study focuses on private wells within the Leinster Granite, guided by previously documented elevated U concentrations (EPA, 2005) and the GSI Tellus stream sediment geochemistry data. In our reconnaissance study of >100 wells, approximately 10% exhibit elevated U concentrations. Uranium concentrations range from a few μg/l to 290 μg/l. A broad positive correlation exists between uranium concentrations, bicarbonate alkalinity and calcium concentrations. The data indicate that U enrichment may involve two separate processes. In the first; low pH, low calcium, low alkalinity groundwaters with relatively radiogenic Sr isotope ratios (>0.714) have elevated uranium, probably indicating weathering at depth. In the second, high-U groundwaters mainly from the northern part of the Tullow pluton exhibit high pH, high alkalinity, high calcium and unradiogenic Sr isotope ratios (<0.714). For the latter group, the formation of uranium-carbonate complexes during the shallow recharge process is thought to be responsible for increasing the solubility of uranium and therefore its concentrations. Batch leaching experiments of granite and associated unconsolidated fluvioglacial deposits are underway to simulate water/rock interactions to further investigate the source(s) of high bicarbonate alkalinity and U in the groundwaters.

Appinite suites and their genetic relationship with coeval voluminous granitoid batholiths

J. Brendan Murphy (bmurphy@stfx.ca)

1Department of Earth Sciences, St. Francis Xavier University, Antigonish, Nova Scotia, Canada, B2G 2W5

Although a plethora of experimental and theoretical studies have examined the role of water in silicic magma evolution, field-based investigations of appinite suites, which preserve visible evidence of the role of water in magma evolution under a range of natural conditions, are rarely integrated with these studies. The abundance of idiomorphic hornblende relative to olivine and pyroxene in rocks of mafic composition, the widespread development of mafic “pegmatites”, together with the presence of “explosion-breccia pipes” indicate that appinitic mafic magmas are unusually abundant in H2O. Appinites have been documented at deep to shallow crustal levels and range from Neo-Archean to Recent in age. Ultramafic-mafic members of the suite share common geochemical traits with shoshonites and whereas intermediate to felsic rocks compare favourably with high-Mg andesites, sanukitoids, tonalite–trondhjemite–granodiorite (TTG) suites and adakites. Many appinitic complexes are emplaced as relatively small coeval satellite bodies with respect to large, composite granitoid batholiths, and several studies imply a genetic relationship between their emplacement, the cessation of subduction, slab roll-back and crustal growth.

Constraining the petrogenesis and tectonic affiliation of appinitic suites can not only provide insights into the behavior of water in silicic melts, it also can provide important clues to sources of orogenic and late-orogenic magmas including voluminous granitoid batholiths, aid in understanding the tectonic evolution of ancient convergent plate margins, and yield insights into the origins of several enigmatic suites.

Probabilistic Surface Heat Flow Estimates Assimilating Palaeoclimate History: New Implications for the Thermochemical Structure of Ireland’s Crust*

B. Mather1, T. Farrell2 (tfarrell@cp.dias.ie) and J. Fullea3

1 School of Geoscience, University of Sydney, Australia

2 Earth and Ocean Sciences, National University of Ireland Galway

3 Geophysics Section, Dublin Institute for Advanced Studies

Regions where surface temperature has increased since past glaciation events, such as Ireland, underestimate the heat output of the Earth unless paleoclimate corrections are applied. We apply probabilistic techniques to quantify the uncertainty of 22 palaeoclimate-corrected heat flow estimates in Ireland, which assimilate multiple surface temperature histories associated with 130 ka of glacial oscillation in the British Isles. Heat flow values increase by approx. 15 mW/m2 after a palaeoclimate correction and provide new insights into the thermochemical structure of the lithosphere. The heat flow regime is broadly delineated by the Iapetus Suture Zone that separates Laurentian to the north and Avalonian terranes to the south (mean surface heat flow of 73 ± 14 and 65 ± 14 mW/m2, respectively). The degree to which heat-producing elements are partitioned into the uppermost crust is described by the differentiation index of a heat flow province. From Bayesian inversion, we determine that radiogenic elements are substantially more differentiated in the uppermost crust of Laurentia (DI = 2.8 ± 1.4) than Avalonia (DI = 1.5 ± 1.3), despite a moderately enriched lower crust (0.8 ± 0.3 μW/m3). This is facilitated by a thin yet highly radiogenic layer in the uppermost crust of Laurentia (3.9 ± 1.8 μW/m3). Extrapolating these results across the British Isles and Newfoundland suggests that heat-producing elements have been more successfully reworked into the upper crust to the north of the Iapetus Suture Zone during continental accretion between Laurentia and Avalonia.

Project DIG: De-risking Ireland’s Geothermal Potential

D. Kiyan1 (duygu@cp.dias.ie), B. O’Reilly1 (bor@cp.dias.ie), C. J. Bean1, J. Fullea1*, S. Lebedev1, P. Meere2 and the DIG team

1 DIAS Geophysics Section, The School of Cosmic Physics, Dublin Institute for Advanced Studies, Dublin 2, Ireland.

2 UCC School of Biological, Earth & Environmental Sciences, University College Cork, Ireland.

* Now at UCM Universidad Complutense Madrid, Spain.

Potential deep (>400m) geothermal resources in low- to medium-temperature settings remain poorly understood and largely untapped in Europe. Project DIG will explore the potential for low-enthalpy geothermal energy on the island of Ireland. It will integrate multi-disciplinary, multi-scale geophysical, geological and geochemical data by means of joint analysis, interpretation, modelling and inversion. Building on tested and validated methods and the rich and diverse datasets from previous and on-going successful Irish research projects (ISLE-MT, IRETHERM, G.O.THERM.3D, SWEMDI, Ireland Array, Tellus, IRL-MT), DIG aims to (i) determine the regional geothermal gradient with uncertainty estimates across Ireland using new and existing geophysical (surface heat flow, active and passive seismics, magnetotellurics, magnetic and gravity anomalies) and geochemical-petrophysical datasets (radiogenic heat production and thermal conductivity), (ii) investigate the thermochemical crustal structure and secondary fracture porosity in Devonian/Carboniferous siliciclastic and carbonate lithologies within and adjacent to the Munster Basin, southern Ireland, using wide-angle seismic, gravity and geochemical datasets, (iii) identify and assess the available low-enthalpy geothermal resources at reservoir scale in the Munster Basin, i.e. Mallow warm spring region, by joint interpretation of electromagnetic and passive seismic methods complemented by a structural geology and new hydrochemistry programme to characterise deep reservoir water composition in order to identify convective pathways and mixing zones using environmental tracers, and (iv) design and implement communication, dissemination and exploitation of the project results to a range of stakeholders (industry, agencies, public). This project is funded by SEAI under the SEAI Research, Development & Demonstration Funding Programme 2019 (grant number 19/RDD/522) and by the Geological Survey Ireland.

A synopsis of Geopark geologist research from County Clare

Eamon Doyle1 (edoyle@clarecoco.ie)

1 Burren and Cliffs of Moher UNESCO Global Geopark, Area Offices Clare County Council, Ennistymon, Co. Clare.

The position of Geopark geologist is quite new in Ireland and would not exist in the Burren and Cliffs of Moher UNESCO Global Geopark without the continued support of Clare County Council and Geological Survey Ireland. This position primarily offers an opportunity for increased geoscience outreach to local businesses and communities beyond the usual range of the established academic and statutory institutions. The position also offers opportunities for research and collaborative academic publications, four of which are the subject of this presentation. The first was with the late Prof. Mike Williams (NUIG) and dealt with exposures of mid Holocene submerged coastal tree stumps and peat along the west coast of Ireland, (Irish Journal of Earth Sciences). The second resulted from a discovery of a new species of crinoid at Doolin, County Clare and gave rise to international collaboration with Prof. Stephen Donovan (Naturalis Biodiversity Centre, Netherlands) which was published in the Proceedings of the Geologists’ Association in 2019. As a result of further fieldwork, a find of tetrapod bones was published in the Irish Journal of Earth Sciences in 2019 with Aodháin Ó Gogáin (TCD) and finally a discovery of trace fossils in the Mississippian limestones of the Burren resulted in a joint project with Paddy Orr (UCD) and John Murray (NUIG) which has been accepted for publication in a memorial issue for the late Prof. R.K. Pickerill in the international journal ‘Ichnos’. Further collaborative projects with these and other international colleagues will result in more publications in the coming years.

3D data for monitoring change in coastal regions

K. Craven1 (kieran.craven@gsi.ie), J. Barry1, R. O’Toole1 and S. Cullen1

1 Geological Survey Ireland, Beggar’s Bush, Haddington Road, Dublin 4

Coastal areas experience change via marine processes and other natural and anthropogenic causes. These changes to coastal geomorphology must be assessed on a range of temporal and spatial scales to understand the evolution of these environments, particularly in the context of projected climate change yielding increased sea-levels and storm frequency. Commercial survey grade unmanned aerial vehicle (UAV), 3D scan equipment, acoustic bathymetry, and data processing and analysis tools are available to coastal managers, engineers and researchers.

This study, undertaken as part of the CHERISH project, analyses 3D data from UAVs, scanning total stations, and acoustic surveys in Irish coastal locations to produce orthoimage mosaics and digital surface models. These products are critical in observing, mapping and predicting change in dynamic coastal environments. Results indicate that combining relevant techniques to produce detailed elevation models provides high-resolution information about emergent and submergent coastal geomorphology on a range of scales for use in coastal mapping, monitoring and management. A quantitative comparison of these models facilitates accurate assessment of change to better understand coastal processes.

Locating flowing conduits in Irish Karst using ground vibrations

Haleh Karbala Ali1 (haleh@cp.dias.ie), Christopher J. Bean1, Caoimhe Hickey2, Billy O’Keeffe3

1 Geophysics Section, school of Cosmic Physics, Dublin Institute for Advanced Studies, Dublin 2.

2 Geological Survey Ireland, Haddington Rd, Beggar’s Bush, Dublin 4.

3 Transport Infrastructure Ireland, Parkgate Bussiness Centre, Parkgate St, Dublin 8.

Water is a critical resource that can range from being either available in short supply or excess, causing floods. In many locations the majority of this supply is underground. In some geological terrains such as karst these underground systems transport water primarily through conduits. Determining the subsurface locations of the dominant flowing structures and their flow rates in such karst systems is a significant challenge. The details of these complex flow networks can, for example, have a first-order control on water supply, surface floods and the locations of seasonal lakes. Current geophysical methods focus on active geophysical imaging of karst structures but usually fail in determining if such structures are flowing. In this work, we take a different approach locating flowing conduits in Irish karst via a multi-method analysis of ground vibrations induced by the flowing conduit through temporary deployments of passive three-component (3C) short-period seismometers. We also try to establish an empirical relationship between the seismic signal and the conduit flow rate. We start by testing the methodology on two surface rivers in Wicklow. This work is the prelude to a larger seismic nodal deployment that will take place in the winter/spring of 2020 in an Irish Karst site.

Uvalas and their relationship to sinkholes (dolines) in an evaporite karst setting

Robert A. Watson1 (robert.watson@ucd.ie), Eoghan P. Holohan1, Djamil Al-Halbouni2, Hussam Alrshdan3, Damien Closson4 and Torsten Dahm2

1 UCD School of Earth Sciences, University College Dublin, Dublin, Ireland

2 Helmholtz Centre Potsdam (GFZ), Section 2.1, Potsdam, Germany

3 Ministry of Energy and Mineral Resources, Amman, Jordan

4 Skymap Global Ltd, Singapore

Enclosed topographic depressions are characteristic of karst landscapes on Earth. The scale and morphological characteristics of such depressions are variable, but the most common depression type is a sinkhole (doline). Certain karst depressions that are much larger than sinkholes and that display gentler slopes and more complex three-dimensional shapes are known as uvalas. Uvalas typically contain numerous sinkholes within them. The developmental relationship between sinkholes and uvalas has been subject of debate, mainly because in classical limestone karst long developmental timescales impede direct observation.

Here, we describe the development of five uvalas and numerous associated sinkholes in an evaporite karst setting on the eastern shore of the hypersaline Dead Sea over a 25-year period from 1992 to 2017. This rapid karst landscape evolution occurs in response to the anthropogenically-driven Dead Sea level fall (ongoing since the 1960s). Our remote-sensing data and field observations show that the sinkholes and the uvalas both formed through subsidence in a very close spatio-temporal relationship. While many sinkholes develop in clusters, the uvalas develop around such clusters as larger-scale, gentler depressions that are structurally distinct in space and time.

The uvalas studied here do not form by a simple coalescence of sinkholes. Instead, these uvalas likely form through subsidence (sagging) in response to distributed subsurface dissolution and physical erosion within a mechanically unstable subsurface volume (e.g. a groundwater conduit network). Sinkholes, on the other hand, represent discrete subsidence responses within that volume to smaller-scale zones of highly localised material removal (e.g. individual groundwater conduits).

Taphonomy of anurans from the Eocene Geiseltal Konservat-Lagerstätte*

D. Falk1 (daniel.falk@ucc.ie), O. Wings2 and M.E. McNamara1

1 University College Cork, School of Biological, Earth and Environmental Sciences, Cork, Ireland.

2 Natural Sciences Collections (ZNS), Halle (Saale), Germany

The Eocene Geiseltal Konservat-Lagerstätte (˜47.5-42.5 Ma) outcrops ca. 20 km SW of Halle, Germany and includes more than 50,000 specimens of fish, amphibians, reptiles, birds, mammals and trace fossils. The taphonomy of the fossils has not been investigated systematically. Here, we focus on the skeletal taphonomy of 140 anurans from Geiseltal. Specimens show a spectrum of preservational states, including (1) near-complete specimens, (2) isolated, articulated skeletal elements (e.g. individual limbs or the vertebral column) and (3) loose associations of disarticulated skeletal elements.

Specimens vary dramatically in completeness (47 ±27 % of elements present) and articulation (73 ±20 % of joints articulated). In general, patterns of loss and disarticulation are similar for bones of the fore- and hindlimb and for both sides of the body. Most specimens retain the cranium (99%), vertebrae (94%), ilium (85%) and femura (85%), but few retain the tarsals (7%), fore- (23%) and hindlimb phalanges (25%) and carpals (30%). There is a striking distal to proximal trend in the loss of bones from the limbs: the femur and humerus are usually present but phalanges, usually absent. Articulation is highest for astragalus-calcaneum (96%), vertebrae (94%), ilium-pelvis (94%) and joints at the carpals and tarsals (91-94%), but hind- (44%) and forelimb phalanges (56%) are more disarticulated. Patterns of articulation within the body are more complex than those for completeness.

These patterns of skeletal taphonomy differ from those in fossil frogs from other important Lagerstätten (e.g. Miocene Libros, Spain), suggesting different regimes for decay, transport and/or depositional controlling preservation.

Ireland’s dinosaurs

Michael J. Simms1 (michael.simms@nmni.com) and David Martill2

1 National Museums Northern Ireland, Cultra, Holywood BT18 0EU

2 School of Environmental and Earth Sciences, University of Portsmouth PO1 3QL

Dinosaur fossils are extraordinarily rare in Ireland, reflecting its stratigraphy rather than the activities of a well-known saint. Mesozoic rocks account for < 1% of total onshore outcrop, are virtually confined to Northern Ireland, have >100 Ma of the Jurassic and Cretaceous missing, and are dominated by facies (arid red-beds; marine clastics and limestones) unlikely to contain dinosaur fossils. Nonetheless, among myriad marine fish and reptile bones from the Jurassic and Cretaceous of Northern Ireland are several fragments with a structure or shape far more typical of the bones of dinosaurs than of any contemporaneous marine reptile.

Identifying exactly what type of dinosaurs these fragments came from is challenging. Of three candidates hailing from just one site, on Islandmagee, one appears to represent the proximal end of a thyreophoran femur, another has proven to be part of a therapod metatarsal, while the identity of a mystery dinosaur/turtle/marine reptile ‘bone’ has finally been resolved. The most recent discovery, part of a therapod femoral shaft from Glenarm, was recognised only in December 2019 having languished in the Ulster Museum’s collections since at least 1923.

The application of machine learning methods to aggregate geochemistry predicts quarry source location: a case study from the Irish aggregate industry*

aTadhg Dornan (dornant@tcd.ie), aGary O’Sullivan, cNeal O’Riain, bEva Stüeken, aRobbie Goodhue

a Trinity College Dublin (TCD), Department of Geology, Museum building, College Green, Dublin 2, Ireland/Irish Centre for Research in Applied Geosciences (iCRAG), O’Brien Centre for Science (East), University College Dublin, Belfield, Dublin 4, Ireland

b School of Earth and Environmental Sciences, University of St Andrews, St Andrews, Scotland, UK

c Unafilliated

Attempting to classify the quarry sources which provided reactive rock aggregate, composed of Carboniferous aged pyritic mudrocks and limestones, to over 12, 500 homes across Ireland has not yet been possible using geochemical data (Dornan, 2019). In this paper, a possible solution to this problem is found by applying machine learning models, such as logistic regression and random forest, to a geochemical dataset of scanning electron microscope energy-dispersive X-ray spectroscopy (SEM-EDS) and Laser ablation-quadrupole-inductively coupled plasma mass spectrometry (LA-Q-ICPMS) of pyrite, and Isotope ratio mass spectrometry (IRMS) of bulk rock aggregate, to predict quarry source location. Using this classification mechanism, it is possible to classify quarry sources with a success rate for individual samples of 100 % based on their geochemistry.

Crustal structures at Rockall Trough by Full waveform inversion

Gaurav Tomar1,2 (gtomar@cp.dias.ie) Christopher J. Bean1,2 and Satish C. Singh3

1 Dublin Institute for Advanced Studies.

2 Irish Centre for Research in Applied Geosciences.

3 Institut de Physique du Globe de Paris

We have performed Full waveform inversion (FWI) on 2D seismic data set that is recorded in 2013-14 by using 10 km long streamer, this 2D seismic line is situated on the North-West margin near the Rockall Bank. Full waveform inversion (FWI) is a powerful technique for obtaining elastic properties of the sub-surface from the seismic data. FWI provides properties of the sub-surface at the scale of the wavelength of the data set. We used travel time tomography on downward extrapolated data set to obtain a smooth starting velocity model for FWI. Downward continuation is a technique that enhances the first arrival and also reduces the computation time for forward modelling in FWI. The velocity model obtained from refraction travel time tomography, indicates the velocity from 1.6-4 km/s for the sediments and we have also observed very high velocity ~ 6-7.5 km/s just 3 km below sea-floor. We have performed FWI using these TTT velocity model as a starting model and inverted the refractions along with the wide angle reflections in the frequency range of 3-10 hz. In FWI results, we get the high velocity structure of ~7.2 km/s as well as some defined geological structures that can be seen in the migrated seismic section. These high velocity structures could be igneous rocks like Gabbro.

Passive seismic exploration: Detecting subsurface interfaces using the ambient noise cross-correlation

Y. Xu1,2 (xuyh@cp.dias.ie), S. Lebedev1, R. Bonadio1, T. Meier3, C. Gomez-Garcia1, C. J. Bean1, D. Hariri1, M. Rezaeifar1 and the PACIFIC Team

1 Geophysics Section, School of Cosmic Physics, Dublin Institute for Advanced Studies, Dublin 2.

2 Institute of Geophysics, China Earthquake Administration, Beijing, China.

3 Institute of Geophysics, Christian-Albrechts University Kiel, Kiel, Germay

Passive seismic methods can extract information on the subsurface structure at a broad range of scales (from basin scales to the Earth’s inner core) from the ambient seismic noise. They have gained the attention of the mining industry due to their low cost and low environmental impact.

To examine the feasibility of the method for imaging deposit-scale anomalies, a dense array has been deployed by the H2020-funded PACIFIC Consortium near Marathon, Canada, with a Cu-PGE deposit beneath it. Covering an area of 2.6 × 3 km with about 1000 seismic stations, the array recorded continuously for 36 days. With noise cross-correlation, we can turn the stations into virtual sources to illuminate the subsurface.

We measured Rayleigh-wave phase velocities and inverted them for a layered subsurface structure. Seismic velocity and layer thickness were both inversion parameters, and we searched for the models that matched the observed data using the fewest model parameters. This inversion approach, together with the high frequency (2–20 Hz) of the dispersion data, enables us to constrain both velocities and interfaces within the top 500 m.

We detected two interfaces at 70 - 90 m and 250 - 330 m depth. The high velocity of the topmost layer is consistent with the locally exposed igneous and metamorphic rocks. Bootstrapping analysis and model-space inversion confirmed the robustness of the models. We demonstrate the applicability of the phase-velocity measurement and interface-detection methods at high frequencies of up to 20 Hz and illustrate their potential utility in mineral exploration.

Characterization of beach dune evolution from Blackwater to Wexford Bay, Co. Wexford using Geophysical and remote sensing approaches

Mathew, Sojan (sojan.mathew@ucd.ie), Gallagher2, Colman, Pellicer, Xavier3, Monteys, Xavier4

1,2 UCD School of Geological Geography, University College Dublin, Belfield, Dublin

3 Land mapping unit; 4 Coastal and Marine Unit, Geological Survey Ireland, Haddington Road, Beggar’s Bush, Dublin,

Quantifying shoreline changes due to the natural processes and anthropogenic activities and its spatio-temporal pattern is a fundamental task for various coastal studies undertaken by coastal zone managers and scientists. This investigation was carried out to determine the erosion/accretion rates and pattern as well as factors that contribute to shoreline changes along 12 km stretch of shoreline from Blackwater to Wexford Bay along County Wexford. Decadal scale shoreline change rates were estimated using 1953, 1972, 1995, 2000, 2005, 2012 and 2018 aerial/satellite imageries within GIS environment. Shore normal transects (ca. 300) at a spacing of 50 m alongshore was used to determine the shoreline erosion/accretion rates. To determine the End Point Rate and Linear Regression of rate of change, the Digital Analysis Shoreline Analysis System (DSAS) was used. The results revealed erosion rates of ca. 1.1 m.a-1 in the Northern reaches (vicinity of Blackwater), ca. 0.2 m.a-1 along central portion and ca. 0.4 m.a-1 accretion along the Southern reaches (Raven Beach and Forest). Based on the long term and short-term field measurements, the major controls on the evolution of beach dune system along the study area may be ascribable to the presence of soft sediment cliffs, sediment supply by river Slaney to Wexford Bay and its north word transport through hydrodynamic processes. In addition, short term coastal evolution has been quantified using remote sensing approaches on a seasonal approach using differential GPS, Terrestrial Laser Scan and UAV. Initial results from these approaches will be also presented in this presentation.

Assessing groundwater resources using Tellus airborne electromagnetics

Y. O’Connell12 (yoconnell@apexgeophysics.ie), C. Brown1, T. Henry1, L. Morrison1 and E. Daly1 (eve.daly@nuigalway.ie)

1 Earth & Ocean Sciences, National University of Ireland Galway, Galway.

2 Apex Geophysics Ltd., Gorey, Co. Wexford.

High-resolution airborne electromagnetic (EM) remote sensing data from County Louth have been used to aid the assessment of groundwater resources and the quantification of hydrological properties of an unconsolidated coastal clay-sand-gravel aquifer. The AEM data have been integrated with ground-based electrical resistivity data, and both data sets have been inverted to infer sub-surface electrical conductivity associated with variable pore fluid salinity and clay content. By using theoretical models to connect these microscale electrical properties with the macroscale conductivity inferred from the data, it is possible to constrain the porosity distribution in clay-sand-gravel mixtures after calibration with field measurements of cation exchange capacity, grain size distribution and pore fluid salinity. The hydraulic conductivity distribution with depth can be estimated using a variety of theoretical models calibrated with field hydraulic conductivity measurements. AEM data can assist with the identification of groundwater resources and their quantification in clay-sand-gravel aquifers but require calibration even if this consists only of limited surface electrical resistivity and/or electromagnetic data linked with hydrogeological data.

New Tellus Geophysical Data for southeast Ireland and electromagnetic inversion results from Limerick region

R. Scanlon1 (ray.scanlon@gsi.ie), B. McConnell1, M. Ture1, M. Muller1 and J. Hodgson1

1 Geological Survey Ireland, Beggars Bush, Dublin 4

Tellus is the Geological Survey Ireland airborne geophysical and ground geochemical mapping programme, providing high quality data for geological mapping, resource assessment and environmental management. Processed data from the most recent airborne survey (Block A7), carried out over southeastern counties in summer 2019 are now available to download from www.gsi.ie/tellus. The data have been seamlessly merged with previous survey phases and coverage now extends to 70% of the country. Data released today include: magnetic field, electromagnetic and gamma-ray spectrometer data flown at a nominal survey altitude of 60m at 200m line spacing on a N165° bearing.

The geophysical data from the A7 block show fantastic detail in this region of complex and varied geology. Strong local magnetic variations are mapped in the Ordovician host rocks of the Leinster Granite batholith, some of which is due to volcanogenic sequences but others of which are not explained by surface geology. There is a broader regional increase in magnetic intensity towards the south, particularly demonstrated by the magnetic Carnsore-Saltees and Ballynamuddagh granites. The electromagnetic resistivity data have mapped regional lithological boundaries as well as subtle variations within individual units.

We also present new datasets derived from inverted EM data for the A5 survey block over Limerick flown in 2018 and 2019. These data have been derived using the aEMpy software developed by DIAS, with resistivity depth slices down to 60m, along with EM cross-sections for the survey area.

Abstracts of Posters

in alphabetical order of author

Titles marked with * are eligible for student prize

Investigating the variability of provenance signal within a sedimentary basin*

B. Anders1 (b.anders1@nuigalway.ie), S. Tyrrell1,2, J. Murray2, J.R. Graham3, C. Mark4,5, D. Chew4, E. Badenzski5

1 SORT (Sediment Origins Research Team), Earth and Ocean Sciences, School of Natural Sciences, NUI Galway, University Road, Galway.

2 iCRAG (Irish Centre for Research in Applied Geoscience), Earth and Ocean Sciences, School of Natural Sciences, NUI Galway, University Road, Galway.

3 Department of Geology, Trinity College Dublin, College Green, Dublin 2.

4 iCRAG (Irish Centre for Research in Applied Geoscience), Department of Geology, Trinity College Dublin, College Green, Dublin 2.

5 iCRAG (Irish Centre for Research in Applied Geoscience), Department of Geology, University College Dublin, Belfield, Dublin 4.

Provenance analysis investigates the origin and pathway of sediment into a sedimentary basin. Such analysis must consider important processes, such as mixing, which affect sediment from erosion and transportation to eventual compaction. This study investigates spatial and temporal variation in provenance signal within the North West Carboniferous Basin in Ireland, with particular focus on the Mullaghmore Sandstone Formation (MSFm). This mid-Viséan siliciclastic unit represents a fluvial/deltaic system within a largely carbonate-dominant basin filling sequence. Deltas are ideal environments to test provenance concepts, as they can comprise multiple input points from distinct hinterland source terranes as well as variations in depositional facies and associated energy (e.g. delta lobe channels vs interdistributary bay vs delta mouth bars) which can impact the amount of mixing and thus the source signal.

Four near complete lithostratigraphic sections through the MSFm were logged, sampled and analysed using a multi-proxy provenance approach including optical microscopy, U-Pb zircon & apatite geochronology, trace elements in apatite and Pb-in-K-feldspar analysis. The basal channel beds at each study location show varying sources and source components, suggesting the MSFm was not originally one large single interconnected system, at least during onset of sedimentation. At the location positioned most proximal to the river mouth five discrete channel sandstones, spaced throughout the MSFm, display variation in supply through time. This highlights the variability of provenance signal, even through a relatively small section within a medium-sized basin, and firmly emphasises the importance of considering sedimentological context when carrying out provenance work.

Escherichia coli and Pseudomonas aeruginosa occurrence in private groundwater wells in the Republic of Ireland*

L. Andrade1,2,3 (luisa.andrade@ucc.ie), P. Hynds3,4, J. Weatherill1,2,3, J. O’Dwyer1,2,3

1 School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland.

2 Water and Environment Research Group, Environmental Research Institute, Cork, Ireland.

3 Irish Centre for Research in Applied Geoscience, University College Dublin, Dublin, Ireland.

4 Environmental Sustainability and Health Institute, Technological University Dublin, Dublin, Ireland.

Despite its importance as one of the most extracted raw materials worldwide, groundwater remains the least understood element of the water cycle. Compounding this, historical lack of regulation has resulted in a large proportion of private groundwater supplies being inappropriately located, designed, constructed and maintained, leaving consumers vulnerable to the adverse health impacts of contamination events. For example, in the Republic of Ireland (RoI) private domestic wells are associated with the transmission of Verotoxigenic Escherichia coli (VTEC); a waterborne infectious disease, for which Ireland has the highest incidence rate in Europe. As such, it is essential to continuously assess the presence and drivers of potentially harmful bacterial species within these supplies, particularly as they are the main source of drinking water for over 16% of the Irish population (>750,000 people). Accordingly, the present study examined the environmental and anthropogenic factors associated with the occurrence of Escherichia coli, a well-established faecal indicator, as well as Pseudomonas aeruginosa, an opportunistic soil/water resident, in unregulated groundwater private wells in the RoI. Results highlight the prevalence of bacterial contamination in Irish groundwater supplies, with 35 (26.5%) and 8 (6%) of 132 wells analysed (Summer/Autumn 2019) testing positive for E. coli and P. aeruginosa, respectively. While P. aeruginosa were only found in supplies from high (H=6.5%) and extreme (E=6.5%; X=14.3%) groundwater vulnerability categories, E. coli were found across all vulnerability categories. Study findings highlight the persistent issue of microbial groundwater contamination in Ireland and the associated public health risks.

Calci-turbidites in the Mississippian Dublin Basin – or are they?*

Elizabeth Andres1 (elizabeth.andres@ucdconnect.ie), Jonathan N. Turner2, Peter D.W. Haughton1

1 UCD School of Earth Sciences, University College Dublin, Belfield, Ireland

2 UCD School of Geography, University College Dublin, Belfield, Ireland

Whilst our understanding of clastic sediment gravity flows (SGFs) and their deposits is developing apace, less attention has been paid to carbonate SGFs. Visean mixed carbonate-clastic deposits were extensively developed in the deep-water Dublin Basin where they are important for mineral exploration, the construction industry and infrastructural projects involving deep excavations. This poster presents the results of a pilot study integrating detailed petrographical profiling and XRF scanning of representative event beds from: (a) outcrops of the Loughshinny Fm at the type section on the coast at Loughshinny, and (b) a pair of event beds from a core obtained during site investigation work for the Port Tunnel. The aim is to explore the processes operating in carbonate gravity currents also transporting clastic components and to develop better facies models for their deposits. Detailed petrographical work has addressed vertical textural and compositional trends for five event beds with a focus on vertical fraction of different components, particle size distributions and mud contents. Element and element ratio profiles for the beds acquired on cut surfaces using an Itrax core scanner provide continuous compositional trends that act as proxies for silicate clay content, textural trends and the ratio of carbonate to clastic components, although locally silicification complicates interpretation. The petrography and bed profiles highlight well developed banding in several of the event beds, complex grading profiles and thick muddy capping divisions. The bed structure and textures are distinct from calciturbidites and suggest they belong to an increasingly recognised family of turbulence-dampened transitional flow deposits.

This research is funded by a Griffith Geoscience Award of the Department of Communications, Energy and Natural Resources (now the Department of Communications, Climate Action and Environment) under the National Geoscience Programme 2007–2013 (Ireland).

Constraining the rate and magnitude of carbon-cycle change at the transition from the Pliensbachian Icehouse to the Toarcian Hothouse world*

C. Barry1 (barryc14@tcd.ie), M. Ruhl1,2 (micha.ruhl@tcd.ie), R.L. Silva1,2 (ricardo.silva@tcd.ie)

1 Department of Geology, School of Natural Sciences, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland

2 Irish Centre for Research in Applied Geosciences (iCRAG), Trinity College Dublin, The University of Dublin, Dublin 2, Ireland

The Early Jurassic is marked by a major transition from cooler (possibly ice-house) conditions in the Late Pliensbachian to the hothouse conditions of the Early Toarcian (~188–181 Ma). Carbon release driven climatic and environmental change at that time resulted in the widespread development of oxygen-depleted conditions in marginal marine basins and the associated drawdown and sequestration of carbon into organic-rich black shales. Combined, volcanogenic greenhouse-gas release and widespread organic-carbon burial led to major perturbations in the Pliensbachian–Toarcian carbon cycle.

This study presents geochemical data obtained from over 200 rock samples from the Upper Pliensbachian–Lower Toarcian section at La Cerradura in southern Spain. This highly expanded section is unique due its low organic carbon content, persistent oxygenation, and position on the southern Tethyan palaeo-margin.

A range of analytical techniques were used to obtain the concentration of redox sensitive trace metals and δ13CTOC values. With this, we (1) constrain (the timing of) global carbon cycle change and (2) improve our understanding of palaeoclimatic and palaeoceanographic processes that operated during this major climate change event at the Pliensbachian–Toarcian transition.

Remote Sensing, GIS and Machine Learning approaches to aid Soil Characterisation and Drainage Design*

I. Rumia Basu1,2 (R.Basu1@nuigalway.ie), Patrick Tuohy1 and Eve Daly2

1 Teagasc, Moorepark, Fermoy, Cork.

2 School of Earth & Ocean Sciences, National University of Ireland Galway, Galway.

Soil is the second largest natural carbon sink, capturing more carbon dioxide from air as compared to forests and other vegetation. Thus, apart from supporting food production, they also help mitigate the effects of climate change. Soil drainage is the degree and frequency at which the soil is free of saturation. It influences soil nutrient cycling and greenhouse gas fluxes, accurate information on soil drainage conditions is crucial for crop, forestry and other environmental management practices. In Ireland more than 50% of the soils are classified as “heavy” or poorly drained which negatively affects agricultural and farm activities.

The design of agricultural drainage systems on a given site is dictated by the soil characteristics in the near surface (<2m depth), which are assessed by the acquisition of information on soil moisture, and soil type and hydrology. Such data is conventionally acquired by in-situ point sampling techniques in shallow soil horizons which is costly and time consuming. Remote sensing has the potential to provide a solution by providing simultaneous coverage of large geographic areas, quickly and in a cost effective manner. This PhD project aims to use remote sensing derived information on soil status and texture in machine learning algorithms to identify and map drainage areas at a variety of spatial scales. Through this study, we aim to come up with novel solutions to identify and map drainage characteristics of soils through remote sensing and aid in providing solutions to better management of agricultural lands.

Present-day principle horizontal Stress orientation from borehole image logging along the Hikurangi Subduction Margin

E. Behboudi1 (effat.behboudi@ucdconnect.ie), D.D McNamara2, I. Lokmer1, T. Manzocchi1, L. Wallace3, D. Saffer4, P. Barnes5, I. Pecher6, H. Lee7, G. Kim8, W. Hung-Yu9, K. Petronotis10, L. LeVay10, Expedition 372 & 375 Scientists10

1 School of Earth Sciences, UCD

2 Department of Earth, Ocean and Ecological Sciences, University of Liverpool, UK

3 Natural Hazards, GNS Science, Lower Hutt, New Zealand

4 Department of Geosciences, Penn State, USA

5 NIWA, New Zealand

6 School of Environment, University of Auckland, New Zealand

7 National Institute of Meteorological Research, South Korea

8 Korea Institute of Geoscience and Mineral Resources, South Korea

9 Institute for Research on Earth Evolution, Japan Agency for Marine-Earth Science, Japan

10 International Ocean Discovery Program, Texas A&M University, USA

Episodic slow slip earthquakes have been recorded along of the Hikurangi Subduction Margin (HSM), New Zealand. The mechanics behind of slow slip earthquakes and their relationship to normal earthquakes and tremors are not well constrained, and so they represent a challenge to the development of hazard models for this region of New Zealand. Variability in stress orientations and magnitudes along and across the HSM may play an important role in controlling the observed spatially variable seismic behaviour. Here we present preliminary analysis of maximum horizontal stress orientation from borehole image log analysis drilled to a variety of depths within the upper 3 km of the hanging wall of the HSM subduction interface. This study collates horizontal stress field orientation data acquired from both IODP Expedition 372, and from industry wells drilled both on and offshore. My analysis reveals that present day maximum horizontal stress azimuth (SHmax) in the subduction hanging wall varies along the HSM strike, from NE-SW (parallel to HSM strike) in the northern HSM, to NW-SE (oblique to HSM strike) in the southern HSM. SHmax azimuth at the frontal thrust in the northern HSM are consistent with SHmax azimuth derived from shallow focal mechanism inversion. In contrast, SHmax azimuth in the south of HSM are oblique to SHmax orientation derived from focal mechanisms inversion. Interestingly, the difference in stress orientations along the HSM is consistent with the variation in seismic behaviour linked to changes in coupling at the subduction interface. At the southern HSM, where the subduction interface is considered strongly coupled, stress field orientations are not consistent with depth and show variability. In the northern HSM, where the subduction interface is considered to be weakly coupled, stress orientations appear broadly consistent with depth.

Crustal structure and multiphase magmatism in the Hatton Basin, offshore Ireland, using seismic reflection and potential field methods*

Laura Bérdi1,2,3,4 (Laura.Berdi@dccae.gov.ie), Manel Prada5, Brian O’Reilly2,3, Patrick Shannon3,4, Peter Haughton3,4

1 Department of Communications, Climate Action and Environment, 29-31 Adelaide Rd, Saint Kevin’s, Dublin 2, Ireland

2 Dublin Institute for Advanced Studies, Geophysics Section, 5 Merrion Square, Dublin 2, Ireland

3 Irish Centre for Research in Applied Geosciences (iCRAG), O’Brien Centre for Science (East), University College Dublin, Belfield, Dublin 4, Ireland

4 School of Earth Sciences, University College Dublin, Belfield, Dublin 4, Ireland

5 Institut de Ciencias del Mar, 37-49 Paseo Marítimo de la Barceloneta, Barcelona, Spain

The Hatton Basin is located next to the continent-ocean boundary in the Irish offshore, east of the Hatton passive volcanic Continental Margin. It is bounded by the Rockall Bank to the east and by the Hatton High to the west. Little is known about its structure and evolution within the context of the North Atlantic opening, given the lack of modern geophysical data.

Here we use modern multichannel seismic (MCS) data acquired with a 10 km-long streamer, together with DSDP data and potential field data to explore the formation processes of the basin. This dataset combined with analogues from the Rockall, Porcupine and Mizen basins suggest the presence of Mesozoic (possibly Jurassic and older) to Holocene sediments. Seismic data also indicates that the evolution of the basin was influenced by several magmatic pulses.

Both magnetic and gravity data show NNE-SSW trending lineaments of positive anomalies, extending from the center of the basin towards the southern margin. Geophysical modelling applied to the seismic profiles showed these anomalies to be intrusions in the middle crust. The parallel nature and orientation of the magmatic bodies suggest that they emerged through pre-existing weak zones of the crust, causing along-axis variation in magmatic activity during basin formation.

This publication has emanated from research supported in part by a research grant from Science Foundation Ireland (SFI) under Grant Number 13/RC/2092 and co-funded under the European Regional Development Fund and by PIPCO RSG and its member companies.

The impact of organic matter on heavy metal bioavailability in urban soils: experimental and field-based approaches*

H. Binner1 (hannah.binner@ucc.ie), T. Sullivan1,2 and M. McNamara1,2

1 UCC School of Biological, Earth and Environmental Sciences, University College Cork, North Mall, Cork, Ireland.

2 Environmental Research Institute, Cork, Ireland.

Soil contamination is widespread across Europe, but there is currently a lack of data concerning contamination of urban soils by heavy metals in Ireland. This research will focus on a systematic survey of soils from recreational areas (playgrounds, sports grounds and public parks) across southern Ireland in order to determine heavy metal concentrations in urban soils. At each site, soil samples will be collected (up to 100 samples per site) at a depth of 10 cm using an auger. Samples will be screened using portable XRF in order to identify specific sample locations and sites with elevated heavy metal concentrations. Synchrotron-XANES will reveal the oxidation state (i.e. bioavailability) of metals of interest. The research will also determine the extent to which metal bioavailability is linked to the type and amount of organic matter present. This study will provide critical baseline data on the extent of urban soil contamination by heavy metals in recreational areas in southern Ireland, providing essential data for future policy development and bioremediation strategies.

The Distribution of Energy Critical and Precious Metals at the Scale of a Porphyry Copper Deposit*

M. Brodbeck1* (brodbecm@tcd.ie), S.H. McClenaghan1, B.S. Kamber1,2, P. Redmond3

1 Trinity College Dublin, iCRAG, Department of Geology, Dublin 2;

2 School of Earth and Atmospheric Sciences, Queensland University of Technology, Brisbane City, QLD 4000, Australia;

3 Kobold Metals, 64 Shattuck Square, Suite 210, 94704 Berkeley, California, USA;

With the increasing demand for critical raw materials in modern energy-related technologies, energy critical elements (ECEs) will potentially be recovered as by-products from porphyry copper deposits, e.g. Ag, Pd, Te, Bi, Co, Ga, Ge and In. However, even if some ECEs are already recovered, for example Te from anode slimes in the copper refining process, their deportment in copper ores has received little research attention. This gap in knowledge is limiting more effective recovery. The same applies to elements that might incur refining penalties (e.g. As, Cd, Sb and Sn). By informing geometallurgy, element deportment studies can thus potentially promote economic and ecologic benefits by improving recovery, adding value to ore resources and helping to reduce the dispersion of deleterious metals into the environment. This study focused on the deportment of ECEs and precious metals in the north-western high-grade section of the Bingham Canyon Cu-Mo-Au porphyry deposit. Contained Cu-(Fe-) sulphides were characterised with scanning electron microscopy and analysed by laser ablation (LA) ICP-MS. Ratios of copper (iron) sulfides were found to exert principal control over the chalcophile trace element budget. The abundance of bornite and digenite primarily controls the Bi and Ag- budgets and significantly affects variations in Te and Se. Chalcopyrite predominantly controls the Co, Ga and In budgets. By contrast, Ge, As, Cd, Sn, Sb and Au are not significantly controlled by the major sulfides, indicating their residence in accessory phases. Gold was found to be primarily hosted in discrete electrum, and Te in telluride grains.

A Pb Isotopic and Trace Element Investigation of Metal Circulation in the Late Bronze Age South Carpathian Basin*

C. Bruyere1 (caroline.bruyere@ucdconnect.ie), J.S. Daly,2 D. van Acken,2 D. Jovanović,3 B. Molloy1

1 UCD School of Archaeology, University College Dublin, Belfield, Dublin 4.

2 UCD School of Earth Sciences, University College Dublin, Belfield, Dublin 4.

3 Town Museum of Vršac, Vršac, Serbia.

Metalwork has long been recognised by archaeologists as an important resource for measuring interaction and the movement of people in prehistory. Lead Isotope and Trace Element analyses has successfully been used to evaluate and characterise the mobility of copper as a raw material.  Contextually, this study focuses on the Late Bronze Age of the South Carpathian Basin where we see the emergence and development of a horizon of mega-forts along important river networks that would have acted as communication corridors for trade: the Danube, Tisza and Mures. At the same time, there is substantial evidence for changes in metal consumption practices such as hoarding. The dynamic mobility of metal can provide a supra-regional perspective to these important social changes during the Late Bronze Age. New lead isotope and trace elements data, presented here, have provided important avenues for further inquiry, contextually and methodologically.

The iCRAGorama podcast project: communicating science through entertainment and online media broadcasting*

Benjamin Couvin1,2 (benjamin.couvin@icrag-centre.org), Anthea Lacchia1,2 and Laura Sinclair2

1 Irish Centre for Research in Applied Geosciences, Dublin, Ireland

2 School of Earth Sciences, University College Dublin, Dublin, Ireland

Disseminating the advances and results of research projects is critical, as they can have a significant impact on society. The importance and value of high-quality communication from research institutes and universities have been more and more recognised in these recent years and the diversification of these communication channels continues to amplify. Entertainment shows, such as podcasts, can be an efficient medium to reach out to audiences that do not necessarily wish to engage with the technical side of research, but are still interested in getting up to date with the latest scientific discoveries. iCRAGorama is a podcast project created by members of the Irish Centre for Research in Applied Geosciences (iCRAG). It is intended to inform various audiences around the world about the projects currently active at iCRAG and in the Irish geoscience research community, through interviews with the researchers engaged in them. These researchers are both early stage and senior, holding a variety of roles. The podcast medium facilitates reaching a high number of people without incurring high costs, whilst offering a platform for scientists to reach out, not only to the general public, but also to other researchers, who may find it difficult to keep up with the achievements and activities of their peers. Through this project, we also wish to foster a sense of community in the geosciences in Ireland and further afield, and are now seeking feedback and suggestions from the Irish geoscience community on what they would wish to hear.

The Earth Observation for Intertidal Mapping and Monitoring (EO-Intertide) project

S. Coveney1 (seamus.coveney@dcu.ie), X. Monteys2, B. Kelleher3 & J.D. Hedely4

1 DCU School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9.

2 Geological Survey Ireland, Beggars Bush, Haddington Road, Dublin 4

3 DCU School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9.

4 Numerical Optics Ltd., Devon, United Kingdom

The EO-Intertide project is funded by Geological Survey Ireland (GSI) as a postdoctoral research project funded by the GSI Geoscience Research programme. The EO-Intertide project is hosted at Dublin City University under the supervision of Dr. Brian Kelleher (Chemical Sciences). The project is generating new methods and new intertidal bathymetric data, collaborating with Dr. Kelleher’s PREDICT research project that is focused upon Dublin bay. The EO-Intertide project is developing a repeatable process that can be applied to extract tidal-shorelines from multidate ESA Sentinel-2 satellite imagery, facilitating the generation of intertidal Digital Elevation Model for the east and southeast coasts. The extracted tidal shorelines will be height-encoded using tidal records and time-coincident modelled tide heights (for areas where tide gauges are unavailable) using regional tidal models. The height-encoded extracted tidal shorelines will be used to generate intertidal Digital Elevation Models (DEMs). The accuracy of these intertidal DEMs will be validated using ICESat-2 Advanced Topographic Laser Altimeter System (ATLAS) photon returns, in conjunction with INFOMAR Multibeam Echosounder (MBES), Airborne Laser Bathymetry (ALB), photogrammetric drone DSM data, Terrestrial Laser Scanning and custom GNSS surveys. The final validated intertidal DEM data will be subsequently applied for the analysis of temporal & volumetric sediment change, turbidity and water quality within Dublin bay, in research collaboration with the Dublin bay PREDICT project at DCU.

Pyrite mineral chemistry in Irish-type Zn-Pb mineralization: fluid movement, ore genesis and exploration*

A. Doran1 (aileen.doran@icrag-centre.org), S. Hollis1, 2, S. Piercey3 and J. Menuge1

1 UCD School of Earth Sciences and Irish Centre for Research in Applied Geosciences (iCRAG), University College Dublin, Belfield, Dublin 4.

2 Geological Survey Ireland, Haddington Road, Beggars Bush, Dublin 4, Ireland.

3 Department of Earth Sciences, Memorial University of Newfoundland, 300 Prince Philip Drive, St. John’s, Newfoundland, Canada A1B 3X5.

Zinc has an important role in our transition to a more sustainable future. With applications in several renewable technologies, agriculture and infrastructure, zinc demand will likely rise in the near future. Ireland has been a major contributor to world Zn-Pb production since the 1980s, with five Zn-Pb mines and over twenty sub-economic prospects discovered. However, with the 2015 closure of the Lisheen Zn-Pb mine, Navan is the only operational Zn-Pb mine in Ireland, making the discovery of new zinc deposits a priority.

Pyrite mineral chemistry studies have been used to aid exploration in several deposit types, including SEDEX and MVT deposits. These studies have revealed specific trace element variations (e.g. Mo, Ag), which define geochemical halos around mineralization. Work on the distal, Island Pod orebody in Lisheen, reveals similar trends, with mean concentrations of Co, Ni, Tl and As being 40-80 % higher in the ore zone than the surrounding sub-economic halo. Pyrite grain-scale variations have also been identified, providing insight into the fluid evolution of the system. Systematic increases in Co and As from pyrite cores to rims are commonplace, confirming precipitation from distinct pulses in a continuously evolving system. A detailed deposit scale investigation across the wider Lisheen deposit is currently in progress.

Through the application of pyrite trace element studies to carbonate-hosted Zn-Pb deposits, we can greatly enhance understanding of deposit development. This will lead to more targeted exploration and the development of vectors towards mineralization.

Ichthyoliths and tetrapod bits from the Clare Shale Formation (Bashkirian, Pennsylvanian), Co. Clare, Ireland

Eamon Doyle1 (EDoyle@clarecoco.ie), Aodhán Ó Gogáin2

1 Burren and Cliffs of Moher UNESCO Global Geopark

2 Department of Geology, Trinity College Dublin, College Green, Dublin 2.

The Pennsylvanian Clare Shale Formation ranges from the Alportian to Kinderscoutian substages in northern County Clare. Fossils reported from the formation include ammonoids, bivalves, crinoids and plant material. Herein we report on the first assemblage of vertebrate material found from the Clare Shale Formation. The Clare Shale Formation crops out along a storm beach south of Doolin and it is in loose slabs along this beach that the disarticulated vertebrate material has been found. Initial vertebrate material includes actinopterygian scales, acanthodian spines, a chondrichthyan dorsal spine and a tetrapod limb bone and pelvic element. This collection is expected to be expanded upon with additional field work to collect material. The material from the Clare Shale Formation is expected to play a role in understanding larger Pennsylvanian vertebrate issues, including the diversification of tetrapods at the onset of the Pennsylvanian and understanding fish cosmopolitanism throughout Euramerica during this period.

Examining the Geology and Describing the Palaeoenvironment of the Kiltorcan Formation on Kiltorcan Hill, County Kilkenny*

C. Ess1 (c.ess@student.ucc.ie), J. David1 (d.jarvis@ucc.ie)

1 UCC School of Biological, Earth & Environmental Sciences, University College Cork, Distillery Field, North Mall, Cork

This project was undertaken to gain a better understanding of the palaeoenvironment of the Kiltorcan Formation, laid down during the Late Devonian, through examining the sedimentology, stratigraphy, and palaeontology of the beds. Detailed sedimentary logs were created of the localities in Kiltorcan New Quarry, which showed both lateral and vertical variation in beds, as well as the abundance and diversity of fossil specimens. The primary depositional environment is believed to be fluvial, with some terrestrial beds also present. The finding of Archaeopteris leaves in the newest section of the quarry (Locality 9) suggests these beds are connected to those of the famous 1850’s Old Plant Quarry. There was a high abundance of Cyclostigma kiltorkense fossils at Locality 7, likely deposited within a point bar, but no other fossil species were found.

Morphology and structural control of dolines (sinkholes) in the Burren, Co. Clare, as revealed by a high-resolution digital surface model

Simone Fiaschi1* (simone.fiaschi@ucd.ie), Robert A. Watson1 and Eoghan P. Holohan1

1 UCD School of Earth Sciences, University College Dublin, Dublin, Ireland

* Now at: School of Science and Engineering, Tulane University, New Orleans, LA, USA

The Burren in Co. Clare is world-renowned for its distinctive karst landscape of terraces, bare-rock pavements, clints and grykes. This landscape is formed by aqueous dissolution of limestones of Carboniferous age. A suite of veins of calcite and/or silica cut through the limestones, and these veins are visible in the landscape as roughly N-S orientated lineaments. These veins act as key structural horizons for subsurface conduit and cave development in the Burren, which is widespread. The aim of this study is to determine the extent to which these veins also control the development of surface karst features such as enclosed depressions, the most common of which are termed dolines or ‘sinkholes’.

Since the 1950s, low resolution of morphological data has inhibited systematic mapping and morphometric description of the Burren’s karst depressions. Recently-created high-resolution datasets now enable study of the morphology of the Burren’s entire 250 km2 area in unprecedented detail. These included optical (RGB) aerial images acquired in 2017 and a related photogrammetric Digital Surface Model (DSM), with respective resolutions of 25 cm and 1 m. We have mapped more than 2500 karst depressions (dolines) in the Burren area by using the high-resolution BlueSky DSM and optical imagery. This new catalogue of dolines represents a 25-fold increase on the existing GSI-hosted database (109 dolines were recorded previously). Our new data demonstrate that vein-associated lineaments control the formation of most of the Burren dolines, though further processes also play a role in producing the complex morphologies observed.

GRACE Monitoring of Groundwater over Ireland – a feasibility study

M. Geever1 (michael.geever@nuigalway.ie), A. Golden1 and E. Daly2

1 School of Mathematics, Statistics and Applied Mathematics, NUI Galway, University Road, Galway.

2 Earth and Ocean Sciences, School of Natural Sciences, NUI Galway, University Road, Galway.

The feasibility of using remote sensing data from the GRACE satellites, jointly operated by NASA JPL and DLR, to determine changes in groundwater storage over Ireland is investigated. The principal objective of this project is to assess the feasibility of constructing a machine learning based model to downscale GRACE data from ~200,000 km2 resolution to approximately 100 km2 or better in order to determine the groundwater component from the GRACE gravitational anomaly data. A functional computational framework has been developed to input GRACE data, land model data from GLDAS and ground truth data from the EPA HydroNet national well depth monitoring network. These data sets are combined to calculate a first order estimate of the time varying changes in groundwater storage over Ireland. The architecture of the analysis scheme is presented here along with preliminary comparisons of timeseries of the three different data sets from April 2002 to June 2017. These timeseries exhibit generally similar features showing a clear seasonal cycle in all cases and good temporal coherence, particularly over the first have of the time period. Work is ongoing to refine this analysis through the addition of other relevant data sets and further development of the algorithms and code base.

Platinum group elements within the nickel sulphide-rich Dooros and Dawros serpentinites, Connemara, Ireland*

E.A Heptinstall1 (e.heptinstall.18@abdn.ac.uk), J. Parnell1

1 School of Geology & Petroleum Geology, University of Aberdeen, Scotland, AB24 3FX

New platinum group mineral (PGM) occurrences are described from the Dooros and Dawros serpentinites in the Connemara national park, Ireland. The Dooros and Dawros localities have comparable compositions to structurally isolated PGM-bearing serpentinites elsewhere within the Caledonides. Platinum group elements (PGE) have important industry applications and may highlight compositional relationships between separate nickeliferous ultramafic intrusions of the Caledonian orogeny. Platinum group minerals have been observed within the Scottish Caledonides in the Shetland and Ballantrae ophiolites and in association with the Portsoy lineament at Corrycharmaig and in the Deveron valley. The nickel-rich Dooros serpentinite intrudes parallel to shear fault zones into the Cornamona formation (580-610 Ma), whilst the Dawros serpentinite comprises the lowermost harzburgite-lherzolite layer of the ultramafic-mafic rocks of the Dawros-Currywongaun-Doughruagh Complex. Eight PGM grains were observed in the Dooros serpentinite, with the two largest grains indicating stibiopalladinite (Pd5Sb2) of average stoichiometry Pd5.01Sb1.98, comparable with nickel-bearing stibiopalladinite in the Shetland ophiolite complex Pd4.99-5.15Sb1.85-2.01. In the Dawros serpentinite, platinum group mineral grain occurrences are rare, with a ~1µm Au(Pd,Pb) alloy grain and a <0.5µm PGM grain with ideal stibiopalladinite stoichiometry of Pd5Sb2. PGE-bearing grains within Dawros were observed in the harzburgite layer, further to trace platinum, ruthenium, rhodium and iridium throughout Dawros, predominantly within Ni-bearing minerals. The PGM occurrence at Dooros, and to a lesser degree Dawros, extends the range of platinum group element mineralisation in serpentinites of the Caledonian orogeny in Britain and Ireland.

Three-dimensional magnetotelluric imaging of Furnas and Fogo Volcanoes, São Miguel Island (Azores archipelago, Portugal)

C. Hogg1 (chogg@cp.dias.ie), D. Kiyan1, V. Rath1, A. Junge2, P. Hering2, R. Carmo3,4, R. Silva3,4 and F. Viveiros3

1 Geophysics Section, DIAS, 5 Merrion Square, Dublin 2.

2 Goethe-University Frankfurt, Germany

3 Instituto de Investigação em Vulcanologia e Avaliação de Riscos, Universidade dos Açores, Portugal

4 Centro de Informação e Vigilância Sismovulcânica dos Açores, Universidade dos Açores, Portugal

Accurate geophysical imaging of shallow subsurface features provides crucial constraints on understanding the dynamics of volcanic systems. The island of São Miguel, Azores (Portugal) is dominated by volcanic systems and can pose a threat to human populations in terms of elevated CO2 and radon degassing along with seismic swarm activity. At Furnas Volcano, intense circulation of volcanic fluids at depth leading to high CO2 outgassing and flank destabilisation poses considerable threat to the local population. The previous electrical resistivity model developed from 39 audio-magnetotelluric soundings that imaged the hydrothermal system of the Furnas Volcano to a depth of 1 km directly beneath the caldera, has now been expanded to include 35 additional broadband magnetotelluric soundings from a recent field campaign conducted in 2018, to image deeper and broader to gain new insights into the regional context of the Furnas volcanic system. The resistivity model constructed from high-frequency dataset delineated two enhanced conductive zones, one at 100 m and another at 500 m depth, separated by a resistive layer. The shallow conductor has conductivity less than 1 S/m, which can be explained by clay mineral surface conduction with a mass fraction of at least 20% smectite. The deeper conductor extends across the majority of the survey area and is located at depths where smectite is generally replaced by chlorite and being interpreted as aqueous fluids near the boiling point and infer temperatures of at least 240oC. The less conductive layer found between these conductors is probably steam-dominated and coincides within the mixed-clay zone found in many volcanic hydrothermal systems. Preliminary inversions from the deep-probing data indicate continuation of a strong conductive zone towards the south, beneath the 1630 Dome which is the most recent phase of eruptive activity in the multi-caldera complex. During the 2018 field campaign, we have expanded our study to include 50 broadband soundings on the adjacent, volcano Fogo, which dominates the topography of the island and is subjected to seismic swarm activity. This work will present various inversion startegies being applied to the Fogo/Congro region to obtain its most robust geo-electrical structure, which is crucial in understanding any relationships to seismicity and also the geothermal regime beneath.

Using geogenic radon potential to assess designation of radon priority areas in Ireland*

M.Hughes1 (mhughes5@tcd.ie), Q. Crowley1,2

1 Department of Geology, Trinity College, Dublin, Ireland

2 Centre for the Environment, Trinity College, Dublin, Ireland

Radon is a radioactive gas which emanates from rock, soil and water. Exposure to radon and its daughter products is associated with an elevated risk of developing lung cancer. Ireland has a population weighted indoor radon concentration of 98 Bq m-3 resulting in an estimated 300 annual lung cancer cases per year, representing approximately 12% of the annual lung cancer cases.

This research focuses on a karstic region of SE Ireland, which features some exceptionally high indoor radon concentrations (65,000 Bq m-3), even though it is not classified as a “high radon” area on the national legislative map. Here we demonstrate the use of measuring sub-soil radon concentrations and sub-soil permeability, in order to construct a radon potential (RP) map of the area. Extremely high sub-soil radon concentrations (>1443 kBqm-3) and radon potential values (>200) are spatially associated with Namurian shales, interbedded with limestone. Overall, we classify the study area as high radon potential (>35) using this technique. We suggest all areas underlain by Namurian shales in Ireland should undergo similar radon potential mapping, and if necessary, should be re-designated as “high radon” areas. If deemed appropriate (i.e. where RP >35), such a designation will help to protect the general public from the harmful effects of indoor radon exposure, and will help to lower the incidence of radon-related lung cancer in these areas.

The Geophysical Characterisation of Irish Soil Types*

S. Irwin1 (s.irwin3@nuigalway.ie), D. O’Leary1, P. Tuohy2, E. Daly1

1 Earth and Ocean Sciences, National University of Ireland, Galway, University Road, Galway, Ireland.

2 Teagasc, Animal & Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork.

Electrical resistivity methods were used in a shallow surface survey (≤2.5m) to examine the physical properties of a sample of Irish soil types. The survey location, a farm in Rossmore, Co. Tipperary, is part of the Teagasc Heavy Soils Programme, where the soils have been previously classified by Teagasc to a field scale via auger and profile pit methods. The electrical resistivity survey was conducted over an area containing three different soil types. A two-dimensional inversion of the electrical resistivity data was able to detect these three soil types and their extents. Current soil maps of Ireland have a resolution of 1:250,000. The use of geophysical methods, such as electrical resistivity, have the potential to provide a method of improving the resolution of current soil maps to a field scale. This could offer Irish farmers valuable information about the soils on their farms, to support precision agriculture, efficient drainage solutions and fertiliser application. Whilst the methods used in this project may not be realistic in terms of practical application on a broader scale, the results show the effectiveness of the method, paving the way for more efficient geophysical methods such as Electromagnetic Induction to be used to characterize Irish soils.

3-D Magnetotelluric Assessment of the Geo-resources Potential of the Irish Crust

D. Kiyan1,2 (duygu@cp.dias.ie), J. Campanyà3, C. Hogg1, C. J. Bean1,2, S. P. Blake4, J. Fullea5, R. Delhaye1, V. Rath1, P. T. Gallagher1, A. G. Jones1* and R. Scanlon3

1 DIAS The School of Cosmic Physics, Dublin Institute for Advanced Studies, Dublin 2, Ireland.

2 iCRAG Irish Center for Research in Applied Geosciences.

3 GSI Geological Survey Ireland, Dublin, Ireland.

4 NASA Goddard Space Flight Center, USA.

5 UCM Universidad Complutense Madrid, Spain.

* Now at CMTS Complete MT Solutions, Ottawa, Canada.

Quantifying and de-risking the exploration for geo-resources require knowledge of the subsurface. This is true for example for both mineral and geothermal exploration. Often that knowledge is built up by local geophysical studies on areas of interest but the broad deeper context and controls for the system are often missing due to a lack of appropriate deep (e.g. >2 km) geophysical imagery. The primary goal of this project is to develop a deep (range 5-100 km) 3-D electrical conductivity model of Ireland’s crust and uppermost mantle using magnetotelluric (MT) method. Deep probing MT imaging yields information on the structure, composition and temperature of Earth’s crust and upper mantle, and can detect processes associated with mineralisation and areas of high temperature and or permeability related to promising geothermal targets. It will also help better illuminate the deep geology of Ireland, particularly in the context of the mechanisms of the Caledonian and Variscan Orogenies that formed Ireland, the emplacement of its sizable granites, and the intraplate basaltic volcanism that followed the opening of the North Atlantic and created the famous Giant’s Causeway and other features. In the framework of Space Weather ElectroMagnetic Database for Ireland, project funded by the Geological Survey Ireland, we acquired long-period MT (LMT) data at over twenty stations in 2018. Since June 2019, new LMT data are being acquired at twelve stations. This contribution will present analysis and modelling results of these data together with the legacy data collected at over thirty stations as part of the ISLE-MT project.

A Geological Map of the Melmore Head Area of the Rosguill Peninsula, North West Donegal*

B. Latimer¹ (116323646@umail.ucc.ie), J. Reavy¹ (j.reavy@ucc.ie)

1 School of Biological, Earth and Environmental Sciences, University College Cork, Cork

The Melmore Head area of the Rosguill Peninsula was mapped at a scale of 1:5000 as a thirty-day final year undergraduate mapping project from University College Cork.

The area consists of a sequence of Dalradian Supergroup metasediments, metadolerite associated with pre-Grampian igneous activity, as well as a series of igneous intrusions associated with post-Caledonian magmatism. These lithologies record a complex sequence of metamorphism, deformation and magmatism. Within the range of Dalradian metasediments, an array of marine environments are preserved representing a marine regression. This sequence was then intruded by mafic intrusions and underwent metamorphism and deformation the Grampian and Caledonian orogenies. Post-Caledonian magmatism then resulted in the emplacement of the Fanad Pluton.

There has been very little published research on the emplacement of the Fanad Pluton and how it relates to the rest of the Donegal Batholith. Based on the analysis of both major granodiorite bodies in the area with a focus on mineral foliations, shear sense indicators from enclaves and xenoliths and intrusion-country rock boundaries, a model is proposed for the emplacement of the pluton. This model suggests ascent within a north-south trending shear zone on the eastern side of Melmore Head with magma subsequentially being emplaced westwards across the Rosguill Peninsula.

The Platform for Atlantic Geohazard Risk Management: using Citizens Observatories to monitor geohazards in Ireland.

K. Lemon1 (klem@bgs.ac.uk), K. Parker1 and E. Holohan2

1 Geological Survey of Northern Ireland, Dundonald House, Upper Newtownards Road, Belfast.

2 University College Dublin, School of Earth Sciences, Science Centre – West Belfield, Dublin 4.

The Platform for Atlantic Geohazard Risk Management (AGEO) is a new project co-financed under the Interreg Programme for the Atlantic Area. AGEO is being led by the University of Lisbon, Portugal with 12 partners from across Spain, Portugal, France, Ireland and the UK.

The project will see the launch of several Citizens’ Observatory pilot projects on geohazards according to regional priorities. The aim is to encourage local communities to actively participate in geohazard monitoring, and to enhance local capacity in risk management.

In total there will be seven pilot Citizens’ Observatories, two of which will be on the island of Ireland. One pilot is being led by the Geological Survey of Northern Ireland focusing on peat mass movement on Cuilcagh Mountain, Co. Fermanagh (part of the Marble Arch Caves UNESCO Global Geopark). The other is being led by University College Dublin focusing on slope instability at the Cliffs of Moher, Co. Clare (part of the Burren & Cliffs of Moher UNESCO Global Geopark).

In addition Citizens’ Observatories, the project aims to encourage regional-level uptake and use of products and services provided by European spatial data infrastructures such as Copernicus. The goal is to incorporate the use of this into the Citizens’ Observatories to ensure that effective risk management for geohazards can be developed.

The first of the pilot Citizens’ Observatories will be in place by Summer 2020 and will be accompanied by a programme of public engagement and education to ensure that its effectiveness is maximised.

For more information please see www.ageoatlantic.eu

The Geochemistry and Potential Sources of Sulphur in Irish Rivers

W.B. Lyons1 (lyons.142@osu.edu), A. Szynkiewicz2, S. A. Welch1, D. F. Smith1, M. A. Diaz1, P. Croot3, T. Henry3, and A.E. Carey1

1 School of Earth Sciences, The Ohio State University, Columbus OH USA.

2 Department of Earth and Planetary Sciences, University of Tennessee, Knoxville TN USA.

3 Department of Earth and Ocean Sciences, National University of Ireland Galway

Between March 2018 and March 2019, we collected 100 river and stream samples throughout Ireland. The sample collection included 21 of the 22 largest rivers by flow, and three transects of the River Shannon. These samples were analyzed for a number of dissolved constituents including major, minor, and select trace elements. An overview of all the data was presented at IGRM last year. We now present a systematic discussion of the geochemistry of dissolved SO4 in these waters, and describe how the concentration varies geographically with respect to distance from the west coast and with catchment lithology. In general, the Cl/SO4 molar ratio decreases away from the coast and riverine SO4 concentrations vary from 19 to 385 µmol/L. There are 17 samples whose SO4 concentrations are higher than their HCO3 concentrations, and in most of these the Ca+Mg/HCO3 molar ratios are >0.5 indicating a source of Ca+Mg other than carbonate dissolution. Stable S isotope analyses were completed on seven samples in order to assess the source of the dissolved SO4. The isotopic values range between 9.46‰ and -4.56 ‰, with the most enriched samples associated with the highest fraction of bogland in the catchment. The role of bogs in controlling S geochemistry in these systems will be discussed, especially in light of potential future changes in bog hydrogeology. The possible contribution from evaporite dissolution and pyrite oxidation will also be reviewed.

Modelling and Monitoring Geomagnetic & Geoelectric Fields in Ireland*

John Malone-Leigh1,2 (jmalonel@tcd.ie), J. Campanyà3, P. T. Gallagher2, J. Hodgson3, J. McCauley2, D. Kiyan4, C. Hogg4, S. P. Blake5

1 School of Physics, Trinity College Dublin, College Green, Dublin 2, Ireland.

2 Astrophysics Section, Dublin Institute for Advanced Studies, 31 Fitzwilliam Place, Dublin 2, Ireland.

3 Geological Survey of Ireland, Beggars Bush, Dublin 4, Ireland.

4 Geophysics Section, Dublin Institute for Advanced Studies, Merrion Square, Dublin 2, Ireland.

5 NASA Goddard Space Flight Centre, Greenbelt, Maryland, USA.

Geomagnetic storms are caused by the interaction between the solar wind and the Earth’s magnetic field, which can create spectacular auroral displays, but also pose a risk to power grids, pipelines, and communication and navigation systems. The effects that magnetospheric and ionospheric processes have on ground-based infrastructure is an active area of research in many countries around the world. Here, we describe a new project to: 1) Upgrade the performance of permanent magnetometers at Armagh, Birr and Valentia, and to carry out short-term surveys of geomagnetic variability at other locations to improve the accuracy of geomagnetic extrapolations across Ireland; 2) To establish a workflow for monitoring geoelectric fields in Ireland, and further investigate their relation with the subsurface geology using data from the Space Weather Electromagnetic Database for Ireland(SWEMDI); 3) Update the modelling of Geomagnetically-Induced-Currents(GICs) in the Irish power grid by using more accurate ground conductivity maps, and: 4) Investigate the currents generated in the ionosphere and magnetosphere during geomagnetic storms using 25 years of data from ground-based magnetometers across Europe. The data and services developed during this project will be made available at the Magnetometer Network of Ireland website (MagIE; www.magie.ie). This work is supported by an Irish Research Council Enterprise Partnership Studentship between DIAS and GSI.

Constraining tectonic chronology: Quantifying deformation in quartz via Raman spectroscopy*

*Odhrán McCarthy1,2 (odhran.mccarthy@ucc.ie), Patrick Meere1,2, Hazel Garvie Cook, William McCarthy(3), Mohit Tunwal1,2, Richard Unit1,2, Alberto Resentini(4), Sergio Ando(4)

1 School of Biological, Environmental and Earth Sciences, University College Cork

2 Irish Centre for Research in Applied Geology, O’Brien Centre for Science, University College Dublin

3 School of Earth & Environmental Sciences, University of St-Andrews

4 Department of Earth and Environmental Sciences, University of Milano – Bicocca

Quartz is an abundant and ideal time capsule that records the formation and deformation history of Earth’s crust. However, our understanding of the formation and deformation of quartz is limited due to the absence of a tool to quantify deformation. Here we adduce the first crystal lattice order differentiation of alpha quartz by measuring accumulated deformation using RSA with potential application in both academia and industry. Analysis of two data sets compiling 917,278 Raman spectra are used to characterise Si-O bonds in the SiO4 quartz tetrahedron. We find that the formation and accumulated deformation history of multiple cross-cutting veins containing alpha quartz can be differentiated based on crystal lattice order, phase crystallinity, vein chronology and architecture data provided from RSA. These findings provide a new proxy for constraining tectonic chronology.

Provenance of sediment in Silurian basins of western Ireland from U–Pb zircon dating

B. McConnell1 (brian.mcconnell@gsi.ie), N. Riggs2 and J. Graham3

1 Geological Survey Ireland, Beggars Bush, Dublin 4, Ireland

2 School of Earth and Sustainability, Northern Arizona University, Flagstaff, AZ, USA

3 Department of Geology, Trinity College Dublin, Dublin 2, Ireland

Three distinct Silurian basin successions overstep the tectonic contacts between elements of the Grampian (Taconic) accretionary history of the Caledonian – Appalachian orogeny in western Ireland. New U–Pb detrital zircon data from strata within these basins address sediment provenance as a guide to basin evolution. The broadly coeval, Llandovery–Wenlock Croagh Patrick and Killary–Joyces Country successions have provenance independent of the structural boundaries between their basement Grampian elements. Proterozoic zircon populations are consistent with sediment sources in the local Laurentian margin and have other distinct sources as well, including possible far-travelled or recycled Tonian grains from Baltica and an Ediacaran–Cambrian peri-Gondwanan source in the late stages of Iapetus closure. Ordovician grains that dominate zircon populations in the Lough Mask Fm. on the western side of the Maum Valley fault zone include ages younger than exposed Ordovician magmatic rocks in the region. In contrast, Ordovician grains are rare in the Lough Mask Fm. on the east side of the fault zone, suggesting that Connemara was planed off by Llandovery time and the fault zone was a barrier to palaeocurrents. The Louisburgh–Clare Island succession is younger than the other two and includes a ca. 423 Ma (Ludlow–Pridoli) tuff. Although the basin is related to regional strike-slip movements along the Fair Head–Clew Bay line, sediment provenance in the Strake Banded Fm. is consistent with sources in local Dalradian rocks together with Silurian volcanic centres.

Gamma ray logging and geological survey of Ordovician placer deposits in the Sarrabus area, SE Sardinia, Italy

M. A. Meloni1, M. Pistis1 (marcopistis75@gmail.com), A. Loi1, A. Funedda1, F. Leone1, M. P. Dabard†,2 and R. Pischedda3

1 Dipartimento di Scienze Chimiche e Geologiche, Università di Cagliari, Italy.

2 Géosciences UMR6118 CNRS/Université Rennes-1, Rennes, France.

3 Freelance geologist, Cagliari, Italy.

† Deceased

Knowledge of placer deposits (PD) is extremely important for multiple scientific purposes, environmental interests and ore deposits (REE).

We propose a multi-level interactive geological and gamma-ray map (1:10,000 scale) of the Upper Ordovician PD of the Punta Serpeddì Formation, which covers an 11 km2 area within the Sarrabus region, a tectonic unit of the variscan basement in SE Sardinia, Italy.

Previous works in the area showed that PD are produced during retrogradation phases in nearshore environments, being interpreted also as isochrones for correlations at basin scale. However, the tectonic complexity of the area (polyphasic deformation associated with tectonic shortening) sometime hinders the identification of both these stratigraphic intervals and the geological contacts (either stratigraphic or tectonic).

This work aims to show the effectiveness of outcrop gamma-ray logging (using a portable spectrometer connected with GPS) for both heavy minerals (HM) prospection and geological mapping in tectonically-complex areas.

High HM concentrations, mainly made of titaniferous, zircon and monazite, are found in these sedimentary sequences deposited in a siliciclastic storm-dominated shelf. These PD show very high radioactivity values linked to abundance of uranium and thorium in zircon and monazite rich deposits.

The distribution of the HM species in the sedimentary facies reflects the hydrodynamic energy of the depositional environment, and is marked by a well-defined radioactive signature (gamma-ray facies), which match perfectly with geology, allowing to easily locate the geological contacts of the formation and its members as well as the most significant PD.

Regional earthquakes observed in 2019 and recent developments at the Irish National Seismic Network (INSN)

M. Möllhoff1 (martin@dias.ie), J.R. Grannell1, D. Craig1, L. Collins1, C. Horan1, M. Smyth1, P. Grange1, C. Hogg1, J.F. Bucas1 and C.J. Bean1

1 Geophysics Section, Dublin Institute for Advanced Studies, 5 Merrion Square, Dublin 2, Ireland

The INSN is operated by the Dublin Institute for Advanced Studies (DIAS) in co-operation with the Geological Survey Ireland (GSI). In 2019 the network detected and reported eight regional earthquakes and 272 quarry blasts. We present details of the regional earthquakes, two of which occurred in County Donegal in April 2019. These two earthquakes were felt widely across southern Donegal and the INSN collected felt reports from the general public. We present this information in felt event maps. A search for five new sites to host additional permanent INSN stations is currently underway. We explain what the main search criteria are and present the location of the search areas that were identified using GIS software. The accuracy of INSN event locations was recently improved by employing a local velocity model for Ireland. Details of this velocity model are presented together with examples of improved estimates of epicentre locations.

U-Pb LA-ICP-MS dating of carbonate veins in orogenic belts*

V. Monchal1 (monchalv@tcd.ie) and D. Chew1

1 TCD Department of Geology, Trinity College Dublin, Dublin 2.

Carbonates can form by a variety of geological or biological processes including in sedimentary or biogenic systems or as a result of hydrothermal activity or carbonatitic magmatism. Recent studies employing U-Pb LA-ICP-MS carbonate dating have confirmed many of the challenges highlighted by Rasbury and Cole (2009), namely that carbonates incorporate a small amount of U or have an unfavorable U/Pb ratio, while the U-Pb system in carbonates is prone to resetting and incorporation of other mineral phases (such as detrital material).

The majority of studies to date are on geochronology of vein carbonates (either in orogenic or hydrothermal systems); this project will primarily investigate dating such targets by U-Pb LA-ICP-MS image mapping (e.g. Drost et al., 2018). This technique circumvents incorporation of other mineral phases or zones of low U content zones by finding zones of pristine (i.e. inclusion-free), high U/Pb carbonate, leading to more accurate and precise dating of the targeted material (e.g. Roberts and Walker, 2016). Targeted samples will include carbonates from the Irish sector of the Variscan orogen, the Alps, and the Irish Zn-Pb ore field.

Europe’s marine minerals: EMODnet geology and Geo-ERA MINDeSEA projects

X.Monteys 1 (xavier.monteys@gsi.ie) and C.McKeon

1 Geological Survey Ireland, Beggar’s Bush, Haddington Road, Dublin 4

The European Marine Observation and Data Network (EMODnet) is a network of organisations supported by the EU’s integrated maritime policy. The EMODnet Geology team recently released a series of products related to topics including Seafloor geology, Seabed substrates, Geological Events and Probabilities, Submerged landscape features and Marine Minerals.

Collated marine mineral data vary widely in genesis. Included in these thirteen types of minerals are: aggregates; hydrocarbons; gas hydrates; marine placers; phosphorites; evaporates; polymetallic sulphides; polymetallic nodules; cobalt rich ferromanganese crust; metal rich sediments; rock, pegmatite and vein hosted mineralisation and sapropel.

With Earth’s population growth, efforts to meet our needs for resources with indigenous supplies continue. Many minerals and critical raw materials form important components in low-carbon and resource-efficient technologies such as electric car batteries and solar panels. A project investigating the metallogeny and geological potential for strategic and critical raw materials on the European seabed called Geo-ERA MINDeSEA has been established and is already using EMODnet Geology Minerals data for analysis.

Information on the types of minerals has relevance to engineering disciplines including extractive industries, beach nourishment and reclamation projects. Environmental and climate scientists examining sea level rise and chemical interactions can utilise information from this dataset and it can assist policy makers in designating areas for protection as well as licencing.

EMODnet Geology IV has now commenced with the aim of maintaining and collating additional marine minerals data from partners of EMODnet Geology. GSI is a partner of EMODnet Geology and MINDeSEA projects

Taphonomy of the Jarrow Tetrapod Assemblage (Langsettian, Pennsylvanian) from Co. Kilkenny, Ireland

Aodhán Ó Gogáin1 (ogogaina@tcd.ie) Gary O’Sullivan2 and Brendan Hoare1

1 Department of Geology, Trinity College Dublin, College Green, Dublin 2.

2 UCD School of Geological Sciences, University College Dublin, Belfield, Dublin 4.

The Jarrow assemblage preserves a diverse collection of tetrapod and fish fossils and is the oldest of the “Westphalian Coal Swamp Assemblages”. Despite its importance in understanding the evolution of early tetrapods and their colonization of terrestrial habitats it is relatively understudied compared to the other coal swamp assemblages. This is due in part to the poor appearance of the fossils, with the boundary between fossil and matrix often difficult to discern. Here cathode luminesce (CL) is used to image cross sections of a vertebra and the dermal osteoderms of an aïstopod (NMI F.16850 and NMI F.14744). Original internal bone morphology is shown to not have been preserved. Instead pockets of bituminous material in the body fossil is surrounded by a groundmass of sphalerite and apatite. Apatite crystals form elongated rectangles uncharacteristic of skeletal bioapatite. Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) was used to measure REE values and date the apatite using U-Pb dating. Normalized to PAAS, apatite shows a very slight depletion in LREE. U-Pb dating gives an age of 302.3±11.7 Ma indicating that alteration and apatite recrystallization occurred after preservation. This contradicts the traditional hypothesis that apatite remobilization was caused by acidic lake bottom waters during the initial burial of the animals. It is more feasible that later diagenetic processes and/or thermal maturation altered the material given the high thermal maturation index of the surrounding sediments.

Use of 3D data in advancing seabed mapping techniques for deep-water habitat classification in submarine canyons*

I. Larissa Macedo Cruz de Oliveira1 (larissa.oliveira@ucc.ie), Aaron Lim1, Luke O’ Reilly1, Kimberley Harris1, John Appah1, Gerard Summers1, Luis Americo Conti2, Andy Wheeler1,3

1 School of Biological, Earth and Environmental Sciences, University College Cork, North Main, Cork.

2 Universidade de São Paulo, São Paulo, Brazil.

3 Irish Centre for Research in Applied Geosciences (ICRAG)/ Marine & Renewable Energy institute (MAREI), University College Cork, Cork.

Submarine canyons and cold-water corals (CWC) are key components of ocean ecosystems given their complex geomorphology and nutrient supply dynamics. The use of photogrammetry in seabed habitat mapping has now been widely used to map and understand these environments. However, research continues to utilise the rendering of 2D images from 3D objects to analyse the seabed which leads to an inevitable loss of data. Consequently, 3D structures (x, y, z) such as CWC can be misrepresented.

This research tackles this concern by focusing on the application of different open-source software techniques to compare classification accuracy results, overall performance and analyse the potential loss of data when using 2D and 3D data. The 3D models of CWC were built utilising Structure-from-Motion applied to image data collected from a remotely operated vehicle (ROV). These models have been analysed with aid of point cloud processing software i.e. CloudCompare and Metashape Agisoft that provide manual and semi-automatic classification through implemented Machine Learning (ML) algorithms such as Support Vector Machines (SVM). The 3D models have been manually segmented into binary classes following a tree classification pattern. Preliminary results show that well-defined objects such as corals and rock fragments can be classified accurately (>90%) whereas features with less defined boundaries and such as coral rubbles presented variable results. Considering the promising results and the work in progress, we expect that this proof concept research will act as a baseline for more robust Machine Learning methods that can be applied to both marine and terrestrial environments.

The distal Senegal Basin, NW Africa – insights into stratigraphy, sedimentology and sediment routing from outcrop, core and modern river sand

C. Pierce1 (colm.pierce@casp.cam.ac.uk), Simon Schneider1, Fiona Hyden2 and Andrew Morton1,3

1 CASP, Cambridge, United Kingdom

2 Oilquest, United Kingdom

3 HM associates, United Kingdom

The island of Maio, Cape Verde and the Deep Sea Drilling Programme (DSDP) sites 367-368, in distal offshore Muritania and Sengal, record the onset and development of Cretaceous abyssal sedimentation directly overlying Upper Jurassic oceanic crust basalts. The sites are located along a 600 km north-south transect (>350 km offshore), which tracks the thickness variations of the sediment pile against a basaltic basement bulge along the westernmost margin of the Senegal Basin.

The initail focus is on Maio, where detailed logs of type sections and biostrat provide improved constraint on the thickness, composition, duration and completeness of the Mesozoic, primarily Lower to Upper Cretaceous rock record. The sedimentology of the studied sections is compared to recent models from seismic data, which emphasise the influence of contourites in the distal Senegal Basin from the early Cretaceous.

The provenance of previously unreported mid-upper Cretaceous sandstones outcropping on Maio and ultimately derived from high-efficiency sediment gravity flows has been assessed via a combination of petrographic, conventional heavy mineral and detrital zircon U-Pb geochronology. This dataset is compared to stratigraphically equivalent, sandstones from the DSDP sites and also with modern river sand compositions from transects of the Senegal, Gambia and Casamance River systems in western Africa.

Some key questions addressed include: 1) Do the siliciclastic sediments represent gravity flows deposits or can contourites be recognised? 2) Can regional sediment routing patterns be inferred? and 3) Can sandstone provenance be tied to proximal basin sectors where active oil and gas exploration is currently focussed?

Mississippian Stratigraphy and Facies evolution on the Galway-Roscommon shelf with special emphasis on the Viséan (MFZ9-13), north-west Midlands, Ireland

M.Pracht1 (markus.pracht@gsi.ie) and I.D.Somerville2

1 Geological Survey of Ireland, Beggars Bush, Haddington Road, Dublin 4, D04 K7X4, Ireland.

2 Prof. em. UCD School of Geological Sciences, University College Dublin.

During the Tournaisian and Viséan the stratigraphic development is the result of the facies evolution from nearshore to outer shelf with localised Waulsortian “barrier” build-ups during the Upper Tournaisian and the gradual, but punctuated, marine transgression in the Viséan. Synsedimentary fault movements, albeit small, during the Lower Viséan controlling subsidence (and sediment supply to the shelf) ad to the complexity of the facies distribution. During the Middle and Upper Viséan (up to the base of the Brigantian) cyclothemic sedimentation developed over a large area, reflecting a quite regular palaeo-topography, largely undeformed during the subsequent Variscan deformation. From the base of the Tournaisian (MFZ1) to the base of the Brigantian (MFZ15), 9 third-order sequences have been tentatively correlated with their equivalent in southern Belgium (Hance and Poty 2002). The lack of data density allow in most cases the interpretation of RST and TST with HST only. One of the striking events is the slow sea level rise at the base of the Ivorian (middle MFZ4) with the deposition of a transgressive system tract (TST) of a third order sequence (sequence 3- corresponding to lower part of the Meath Formation) leading to the first carbonate sedimentation on this part of the shelf. The second important development is the sea level fall followed by sea level rise at the time of the Tournaisian-Viséan transition with the deposition of the transgressive system tract (TST- Kilbryan Fm.) and the highstand system tract (HST- lower/middle Oakport Fm.) of a third order sequence (sequence 5).

Biogeochemical modelling of Irish peatland sites – Insights into the procedures for estimating potential evapotranspiration for long-term average climate input data

A. Premrov1 (premrova@ucd.ie), M. Saunders2 and F. Renou-Wilson1

1 UCD School of Biology & Environmental Sci., Science Centre – West, University College Dublin, Belfield, Dublin 4.

2 Botany Department, School of Natural Sciences, Trinity College Dublin, Dublin 2.

Peatlands in their natural state they can act as an important C sink. However, if they are exposed to anthropogenic changes (such as drainage) peatlands can act as C source. This work is performed as part of the EPA funded AUGER project [http://www.ucd.ie/auger/], which uses the ECOSSE [Smith et al., 2010] process-based biogeochemical model to predict GHG emissions associated with different land use/management of Irish peatlands. During the model spin-up, ECOSSE requires long-term (30 yrs.) average climate input data –i.e. monthly mean temperature, rain and potential evapotranspiration (PET). Presented are insights into the procedures for estimating PET from other climate-parameters obtained from Met Éireann 30 year averages (1981-2010) climate gridded data at 1km resolution in order to use them as inputs into ECOSSE. PET was not included in the datasets and had to be estimated. Used was the Thornthwaite (1948) method, which is well known for its simplicity.

Biogeochemical modelling of Irish peatland sites – Insights into the processing procedures of daily climate input data obtained from ICHEC WRF climate datasets

A. Premrov1 (premrova@ucd.ie), M. Saunders2 and F. Renou-Wilson1

1 UCD School of Biology & Environmental Sci., Science Centre – West, University College Dublin, Belfield, Dublin 4.

2 Botany Department, School of Natural Sciences, Trinity College Dublin, Dublin 2.

Peatlands are known to act as a carbon (C) sink in their natural state, but in case of anthropogenic changes (e.g. drainage) they can act as C source. Biogeochemical models are often used for modelling greenhouse gas (GHG) emissions from different systems, with climate data representing a crucial input [Smith et al. 2010]. This work is performed as part of the EPA funded AUGER project [http://www.ucd.ie/auger/], which uses the ECOSSE process-based biogeochemical model to predict GHG emissions associated with different land-use/management of Irish peatlands [AUGER, 2017]. ECOSSE requires (among others) climate data for the period simulated. Presented are insights into the processing procedures of ICHEC-WRF Irish daily climate datasets [EPA_Climate-WRF, 2019] in order to use them as inputs into ECOSSE. The WRF (Weather Research and Forecasting Model) datasets are available from the ICHEC-ERDDAP v.1.82 [https://erddap.ichec.ie/erddap/files/EPA_Climate/WRF/]. The ICHEC–WRF provides daily 1981-2017 data (temperature, precipitation, potential evapotranspiration) with 2km spatial resolution and in NetCDF-format. Data were processed in R v.3.6.0 using adapted R-scripting and R-packages (“ncdf4”, “raster”) [Boyer, 2017; R Core Team, 2019 https://www.R-project.org/]. The extraction is possible from multiple layers (i.e. 365 days of the selected year) for specified points.

Current plans for upscaling of soil organic carbon predictions for Irish grasslands using the ECOSSE model: Part I – potential application of the LUSII national inventory data

A. Premrov1 (premrova@tcd.ie), J. Zimmermann2, G.M. Afrasinei2, K. Black3, Stuart Green2, M. Saunders1

1 TCD Botany Department, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland

2 Department of Agrifood Business & Spatial Analysis, Teagasc Food Research Centre, Ashtown, Ireland

3 Forestry Division, FERS Ltd, Ireland

The work presented here forms a part of larger SOLUM project, which uses (among others) the ECOSSE process-based biogeochemical model (Smith et al., 2010) to assess the soil organic carbon (SOC) stocks and changes for Irish grasslands under different grassland management practices. Insights into current plans for upscaling of ECOSSE SOC predictions for Irish grasslands from site-scale to country-scale are presented. Site SOC simulations based on input data obtained from various sources (i.e. LUCAS [Tòth et al., 2013], Teagasc SIS [Teagasc, 2018]. LPIS [Zimmerman et al., 2016]) are currently in their final development stages. Current plans for model-upscaling to country-level involve development of grids containing parameters required to run simulations for each grid-cell. Depending on modelling needs, the new LUSII (Land Use and Soil Inventory for Ireland) dataset (Afrasinei, 2019) (which was developed independently from ECOSSE modelling) is currently planned to be aligned with the ECOSSE modelling work or outputs in order to gain potential additional insights into important characteristics of sites used in model simulations.

Current plans for upscaling of soil organic carbon predictions for Irish grasslands using the ECOSSE model: Part II – potential application of soil-grouping from separately developed soil cluster-analysis

A. Premrov1 (premrova@tcd.ie), J. Zimmermann2, K. Black3, G.M. Afrasinei2, Stuart Green2, M. Saunders1

1 TCD Botany Department, School of Natural Sciences, Trinity College Dublin, Dublin 2, Ireland

2 Department of Agrifood Business & Spatial Analysis, Teagasc Food Research Centre, Ashtown, Ireland

3 Forestry Division, FERS Ltd, Ireland

The presented work forms a part of the larger SOLUM project. It focuses (among others) on the current plans for upscaling of SOC predictions for Irish grasslands (under different management practices) from site-scale to country-scale [Premrov, 2020]. Site SOC simulations based on various inputs [JRC, 2018; Tóth et al., 2013; Teagasc, 2018; Zimmermann et al., 2016] are currently in their final development stages, and the plans for model-upscaling to country-level involve development of grids with required parameters (as explained in Part I). Depending on modelling needs, the recently developed cluster-analysis based soil-grouping [Black, 2018] (which was developed separately from the ECOSSE process-based modelling) is currently planned to be aligned with ECOSE modelling work or outputs in order to gain potential insights into important features of soils used in model simulations.

Constraining the rate and magnitude of carbon-cycle change at the end-Triassic global mass extinction, and its temporal link to large igneous province volcanism*

R. Quirke1 (roquirke@tcd.ie), M. Ruhl1,2 (micha.ruhl@tcd.ie), R.L. Silva1,2 (ricardo.silva@tcd.ie)

1 Department of Geology, School of Natural Sciences, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland

2 Irish Centre for Research in Applied Geosciences (iCRAG), Trinity College Dublin, The University of Dublin, Dublin 2, Ireland

The end-Triassic mass extinction (~201 Ma) is represented by a significant and global decline in marine and terrestrial organisms. It has been informally linked to the large-scale and rapid release of carbon greenhouse gasses that resulted in significantly increased atmospheric pCO2 concentrations and a major perturbation to the global exogenic carbon cycle, in response to the emplacement of the Central Atlantic Magmatic Province (CAMP).

This study presents geochemical data from over 200 rock samples collected from the Carnduff core (Larne Basin, Co. Antrim, Northern Ireland). The Triassic–Jurassic transition is marked by significant (eustatic) sealevel fluctuations, with a sealevel lowstand coinciding with the end-triassic mass extinction. Possibly because of this, many sedimentary succession spanning this time-interval are therefore extremely condensed. The Triassic–Jurassic transition in the Larne Basin is, however, 101–102 times more expanded compared to coeveal successions in the European realm, the succession is excellently preserved, and biostratigraphically well-constrained. It consists of alternating marls and mudsones, and limestones, with varying organic carbon content.

Several analytical techniques were used to obtain the concentration of redox-sensitive trace metals and δ13CTOC values, as well as metals indicative for globally elevated volcanic activity. With this, we constrain the timing and magnitude of carbon cycle change and examine elemental footprints left behind during the end-Triassic period, with the goal to improve our understanding of the causes and environmental consequences of volcanogenic carbon release, and the processes responsible for this major mass extinction event.

The Sherwood Sandstone Group as a potential geothermal aquifer across Northern Ireland

R. Raine1 (rob.raine@economy-ni.gov.uk), D. Reay1, Paul Wilson1 and R. Millar

1 Geological Survey of Northern Ireland, Dundonald House, Upper Newtownards Road, Belfast, BT4 3SB, Northern Ireland.

The Triassic Sherwood Sandstone Group (SSG) is a thick unit of sandstones with mostly good reservoir quality. Deposition in fluvial and aeolian environments is reflected in a range of sedimentary facies that have impacted the resulting reservoir quality, which has been further reduced or enhanced by burial-related processes. Data from water, hydrocarbon and geothermal exploration boreholes across Northern Ireland have helped to increase our understanding of SSG aquifers as potential future geothermal energy resources. The SSG is up to 650 m thick and is widely distributed across the Permo-Triassic basins in NE Northern Ireland. The basins are mostly concealed beneath Palaeogene basalts that degrade seismic data quality, so that potential field geophysics, structural and borehole data have been used to model SSG depths. Thin section and core analysis have been carried out to assess the spatial distribution of the best reservoir quality. For many years the SSG was an important source of water for the industrial growth of Belfast and subsequently the sandstones formed the principal target for limited hydrocarbon exploration. The sandstone aquifer is already used for heating and cooling, using heat pump technology, in the Greater Belfast area, where it is relatively shallow and there is potential for this type of geothermal energy use to grow. However, information acquired since the 1980s also indicates hot aquifers at depth within the SSG may represent a far greater resource that could be used as a sustainable low carbon energy source for direct heating applications via the deployment of heat networks.

Results from a thermo-geochronological study offshore West of Ireland*

R. Rateau1 (rateaur@tcd.ie), D. Chew1

1 Department of Geology, Trinity College Dublin - Irish Centre for Research in Applied Geosciences (iCRAG)

In the Irish Atlantic Margin (IAM) large uncertainties remain about the exact timing, magnitude and causes of the main uplift and erosion events. Low-temperature thermochronometers such as apatite fission track analysis by LA-ICP-MS (LAFT) and apatite (U-Th)/He (AHe) can help better constrain these events. We present the results of a large study based on the re-interpretation of published fission track data and new analyses from samples in the offshore West of Ireland. We also present the results of U/Pb dating of apatites and zircons from these samples.

This poster has emanated from research supported in part by a research grant from Science Foundation Ireland (SFI) under Grant Number 13/RC/2092 and is co-funded under the European Regional Development Fund and by PIPCO RSG and its member companies.

Tales from Tellus: A Communications Story

E. Scanlon1, J. Hodgson1 and E. McMonagle2

1 Geological Survey Ireland, Tellus Programme

2 Geological Survey Ireland, Cartography Unit

Tellus is a national programme gathering geochemical and geophysical data across Ireland, which examine the chemical and physical properties of our soils, rocks and waters.

Due to the visible nature of the survey and its potential impact on the public, as the aircraft crosses the skies and samplers visit farms and landholdings, an extensive communications programme has been undertaken to both support the survey operations as well as promoting the uses of the data collected. Communications has taken the form of direct leafleting, national and local media through TV and radio, information lines and social media, as well as engagement with academia and collaboration with other national agencies. The management of the survey is data-intensive; requiring geospatial information, flight plans and comprehensive records of stakeholder engagement. To manage this effectively, Tellus has developed an award winning, easy-to-use system that combines all of this data; which can be used remotely and by multiple operators; the Tellus Communications Viewer (TCV).

A new way in which Tellus is promoting geoscience and science communications is through the development of a Story Map – Tales from Tellus. This story map, officially released here today is an on-going development, using images collected as part of survey activities over the last number of years. These images are geo-located and linked to metadata providing captions and further information about the place to be viewed in a story map format hosted on-line. Tellus will continually update this story map as the survey progresses across Ireland.

Early Cretaceous coastal dynamics and expression of the oceanic anoxic event 1b cluster in the Isle of Wight (Wessex Basin, United Kingdom)

R.L. Silva1,2 (ricardo.silva@tcd.ie), G. Wach3, S.P. Hesselbo4, M. Ruhl1,2, D. O’Connor3

1 Department of Geology, School of Natural Sciences, Trinity College Dublin, The University of Dublin, Dublin 2, Ireland

2 Irish Centre for Research in Applied Geosciences (iCRAG), Trinity College Dublin, The University of Dublin, Dublin 2, Ireland

3 Basin and Reservoir Lab, Department of Earth and Environmental Sciences, Dalhousie University, Nova Scotia, Canada

4 Camborne School of Mines and Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9FE, UK

The late Aptian–early Albian oceanic anoxic event (OAE) 1b cluster is characterized by several carbon cycle perturbations and deposition of high TOC sediments in many locations around the world. This OAE cluster was a significant event in the marine realm, associated with drastic changes in ecosystems and ocean chemistry. However, there is a wide gap in knowledge concerning the response of terrestrial and coastal environments to the environmental drivers of the OAE 1b cluster and the impact of these depositional environments in the global carbon cycle.

The Upper Aptian–Lower Albian in the Isle of Wight (Wessex Basin, United Kingdom) comprises a thick sedimentary succession of sands and mudstones (the Ferruginous Sands, Sandrock, and Monk’s Bay Sandstone formations of the Lower Greensand Group) deposited in estuarine and shallow marine shelf environments. In this study, we have investigated the Upper Aptian–Lower Albian successions cropping out along the southwestern Isle of Wight, analysed for total organic carbon, pyrolysis of organic matter, and δ13C in bulk organic matter.

The integration of our findings from the Wessex Basin Early Cretaceous coastal palaeoenvironments with current modelling efforts will help to clarify the impact of estuaries and wetlands on climate, carbon cycle, and OAEs and help elucidate the factors contributing to present-day issues of coastal anoxia expansion and tidal wetland loss.

Influence of subcatchment geology on river chemistry in the Corrib Catchment*

Devin F. Smith1 (smith.11880@osu.edu), A. E. Carey2, S. A. Welch3, P. L. Croot4, S. Wheeler5, T. Henry6, and W. B. Lyons7

1, 2, 3, 7 School of Earth Sciences, The Ohio State University, Columbus OH, 43210.

4, 5, 6 Earth & Ocean Sciences, School of Natural Sciences National University of Ireland Galway, Galway H91 TK33, Ireland

The influence of lithology on river chemistry has been widely studied in hydrology. It has been demonstrated that river geochemical signatures vary due to differences in underlying geology and that tributaries within a catchment can show considerable variations in chemistry depending on subcatchment lithology. The Corrib Catchment is an ideal location to study subcatchment bedrock influence on river chemistry in Ireland because of the differentiations in subcatchment bedrock. Limestone bedrock underlies the eastern portion of the Corrib Catchment while crystalline metamorphic and granitic bedrock are predominant in the western portion. We demonstrate the influence of lithology on river geochemical signature in the Corrib Catchment through an analysis of the Corrib River and six of its tributaries: Rivers Clare, Robe, Cloon, Cong, Bealanbrack and Owenriff. Samples were collected in 2018 and 2019 and analysed for major ions and nutrients at The Ohio State University. Geochemical and spatial correlations were conducted using our measured solute concentrations and catchment bedrock data from the Irish Geological Survey. Correlations revealed a clear distinction between rivers draining catchments underlined by limestone and by crystalline rock. Results showed strong positive correlations between subcatchment limestone (%) and Ca2+, Ca2+/, HCO3-, Ca2+/Na+, TDS. However, these results also indicated that weathering regimes varied during the sampling period due to changing discharge conditions caused by fluctuations in precipitation. Results from this study demonstrate the strong influence of subcatchment lithology and discharge on river chemical signatures in the Corrib Catchment, contributing to the knowledge base of hydrochemical work in Ireland.

Boreholes 2020: Creating an accessible diamond drill hole database from the GSI Open File archive

L. Smith1 (laura.smith@gsi.ie), E. McGrath1, D. Johnston1, C. Duggan1, M. Bywater1, S. Troy1, R. Rogers2 and G. O’Shea3.

1 Minerals Programme, Geological Survey Ireland.

2 Geological Mapping, Geological Survey Ireland.

3 Information Programme, Geological Survey Ireland.

The Boreholes 2020 project aims to publish all data relating to diamond boreholes, including open file data and GSI corestore scans, via a single searchable database presented in map format via the GSI website.

The Open File database consists of 799 box files of reports relating to mineral exploration carried out in the Republic of Ireland from 1957 to 2002. These include written reports, maps, geophysical data, geochemical data and boreholes logs. These have been scanned and can be accessed through the GSI’s Geodata service by searching for a specific box, file and item location (if known) or through key word search the Goldmine service. However due to variation in borehole name format and incomplete metadata, these results are not always exhaustive.

The Boreholes 2020 database will contain metadata such as Open File Location, borehole length, azimuth and depth, ITM coordinates, coordinate source, year and PL area .

Firstly a physical trawl through of the Open File archive was conducted to document all diamond drillhole mentions and basic information. Next, coordinates from existing internal GSI databases were integrated into the Boreholes 2020 project. These existing databases comprised a verified GSI borehole database, an accompanying unverified borehole database and a borehole database provided by iCRAG with the collaboration and agreement of numerous industry partners.

Holes without coordinates following this integration were manually georeferenced from Open File maps, and where boreholes had more than one coordinate from the various sources, investigations were conducted to deduce which of those coordinates are more accurate.

The hard rock geology of the Irish continental margin – investigation through seafloor observations and submersible rockdrilling*

R. Strachan1 (ruaihri.strachan@ucc.ie), P.A. Meere1, X. Monteys2, A. Mazzini3, A.J. Wheeler1,4,5 and A. Lim1

1 School of Biological, Earth and Environmental Sciences (BEES), University College Cork, Cork, Ireland

2 Geological Survey of Ireland (GSI), Beggars Bush, Haddington Road, Dublin, Ireland

3 Centre for Earth Evolution and Dynamics (CEED), University of Oslo, Oslo, Norway

4 Irish Centre for Research in Applied Geosciences (iCRAG), University College Cork, Cork, Ireland

5 Marine & Renewable Energy Institute (MaREI), University College Cork, Cork, Ireland

The Irish continental margin has been shown to host many vertical structures in which bedrock exposure can be expected, such as fault escarpments and the walls within submarine canyon systems. However, surveying in these areas is difficult, primarily due to issues regarding access and sampling conditions, which are hindered by an unpredictable and harsh working environment. As a result of this, a noticeable contrast exists between the information on Ireland’s terrestrial geology and that of its offshore, due to the lack of both knowledge and detail on observable outcrop. Through the use of seafloor observation techniques, coupled with novel submersible drilling capabilities, this study aims to bring a greater insight into the seafloor geology along the Irish continental margin. An extensive collation of known bedrock exposure in the Irish offshore has been conducted. From multibeam bathymetry, terrain variables calculated for these outcrop locations along the margin are used to further calculate potential bedrock exposure in non-surveyed areas. Using 3D photogrammetry, key bedrock types within the sampled areas have been modelled in order to identify their respective lithologies and structural components. Rockdrill plugs and rock dredge samples have been gathered, and further petrography, Raman microscopy and U/Pb geochronological analysis of these samples is being conducted in order to correlate sampled bedrock exposure to on-land stratigraphic formations. This research aims to bridge the gap between onshore and offshore geological surveying by assessing modern mapping and photogrammetric technology and submersible rockdrilling capabilities. This project is funded by the Irish Petroleum Infrastructure Programme (PIP).

Assessment of semi-automated classification techniques in characterising seabed sediment wave fields*

G. Summers 1,2 (gerard.summers@ucc.ie), A. Lim1,2 and A. J. Wheeler1,2,3,4

1 School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Fields, North Mall, Cork Ireland.

2 Environmental Research Institute, University College Cork, Ireland.

3 Marine & Renewable Energy Institute (MaREI), University College Cork, Cork, Ireland.

4 Irish Centre for Applied Geosciences (ICRAG), University College Cork, Cork, Ireland.

National mapping programs (INFOMAR and MAREANO) and global efforts (Seabed 2030) acquire large volumes of multibeam echosounder (MBES) data to map large areas of the seafloor. Developing an objective, automated and repeatable approach to extract meaningful information from such vast quantities of data is now essential. Many automated or semi-automated approaches have been defined to achieve this goal. However, such efforts have resulted in classification schemes that are isolated and bespoke, therefore it is necessary to form a standardised classification method. Sediment wave habitats are the ideal platform for this as they are dynamic, form complex morphologies and important habitats for various organisms. Here, we apply 3 techniques: Object-based image analysis (OBIA); a bathymetry and reflectivity-based estimator for seafloor segmentation (BRESS) algorithm; and Benthic Terrain Modeler (BTM) to assess and compare the accuracy and precision of each method. Initial findings show that the BRESS algorithm requires fewer adjustments to classification settings than that of BTM or OBIA to create a classification that reflects the bedform features. We expect that the BRESS approach will help characterise seabed bedforms aiding seabed habitat assessments with applications for temporal analysis.

An investigation of Rare Earth Elements (REE) in Irish marine Transitional zones: A case study in Kinvarra Bay*

J.Symons1 (Jamessymons97@gmail.com), P. Croot1,2, N.Rathnayake Kankanamge1, L.Morrison1, S. Fennell1 and S. Fatimatuj1

1 Earth and Ocean Sciences, School of Natural Sciences and Ryan Institute, National University of Ireland Galway

2 Irish Centre for Research in Applied Geoscience (iCRAG@NUIG), Earth and Ocean Sciences, National University of Ireland, Galway, Ireland

The spatial and temporal distribution of Rare Earth Elements (REE) in transitional water bodies is poorly understood and little studied in Ireland, to address this research was undertaken as part of the EPA funded NUTS&BOLTS project, with the aim to investigate REE variation in coastal and terrestrial water bodies on both temporal and spatial scales. The methodological approach used a SeaFAST pre-concentration system in conjunction with an ICP-MS allowing very precise REE measurements in saline water at the pM (10-12 M) level. This allows the sources and processes which dominate REE distribution in Irish transitional water bodies to be better understood and facilitates the identification of potential anthropogenic effects on dissolved REE concentrations. The results show that dissolved REE concentrations can be conservative or non-conservative with regards to salinity. The results also show that carbonate complexion and colloidal iron adsorption are the major sinks of REE.

In conclusion, the findings from this research demonstrate that REE trends could be used to indicate potential contamination in transitional water bodies which can be used as a future criterion to assess transitional water bodies’ water quality. In addition, these signals could provide insight into how transitional water bodies have evolved over time and may be useful as indicators of palaeo-environment in sedimentary rocks.

Tidal Mixing and Bottom Density Fronts along the South-West coast of Ireland*

C. Tierney1 (c.tierney11@nuigalway.ie), M. White1, S. Fennell1

1 Earth and Ocean Sciences, National University of Ireland, Galway, University Road, Galway, Ireland.

During 31st July-8 th August 2019 a cruise was undertaken on the R.V. Celtic Voyager along the south and west coast of Ireland to examine whether top marine predator activity could be linked to physical structures within the water column. Six CTD transects were taken to examine the hydrologically and biologically dynamic region along the shelf. Strong frontal structures were visible along the south coast with relatively stronger coastal jets and enhanced biological activity associated with them. Flows of up to 30 cm/s are recorded in proximity to the frontal structures here. As the 53˚N transect is approached more gradual horizontal changes in temperature/salinity occur with weaker frontal systems and less biological activity recorded. Along the west coast a northward residual drift was visible when calculated from geostrophic flows, this residual drift played a key role in linking the intermittent regions of relatively strong coastal jets previously recorded along the southwest and northwest coast. Understanding the distribution of frontal systems and their associated coastal jets is essential for mapping HAB’s and nutrient pathways, locating regions of enhanced biological activity and diversity and acting as a link between seas to the north and south of Ireland

Critical Metal Potential of the Irish-type Zn-Pb deposits

Lingli Zhou1 (lingli.zhou@ucd.ie), Steven P. Hollis1, Sean Mc Clenaghan2,3, John Güven1,3, Sean Johnson1,3, and Murray Hitzman1,3

1 UCD School of Earth Sciences, University College Dublin, Belfield, Dublin 4.

2 Department of Geoscience, Trinity College Dublin, College Green, Dublin2.

3 Irish Centre for Applied Geosciences (iCRAG), University College Dublin, Belfield, Dublin 4.

The demand for critical metals continues to grow, driven by the functioning of renewable energy, environmental, and technological innovations. Traditionally, critical metals (e.g. Cobalt, Indium, Germanium) have not been targeted for exploration and extraction in Ireland. However, many studies have shown that these metals are present in abundance in Zn-Pb ore minerals (e.g. sphalerite, Wilkinson et al., 2005). This presents an excellent opportunity to investigate the abundance of such metals and its potential in Irish Zn-Pb deposits. With the development of advanced multi-element mineralogical microanalysis, e.g., laser-ablation inductively-coupled plasma mass spectrometry (LA-ICPMS), it is now possible to precisely constrain the mineralogical deportment of critical metals, and the range and variation in absolute concentration down to sub ppm level. Furthermore, the recent development of robust LA-ICPMS mapping technique allows for visualising the distribution of critical metals in ores at micrometre-scale spatial resolution in order to optimise the extraction process. In this contribution we will present a short introduction of the project and the methodology to be used to characterise the abundance and distribution of critical metals in the Irish-type Zn-Pb deposits.

First Author Index

A

Ali, H.K. 19

Anders, B. 24

Andrade, L. 24

Andres, E. 24

B

Barry, C. 25

Basu, I.R. 25

Behboudi, E. 26

Bérdi, L. 26

Binner, H. 27

Brodbeck, M. 27

Bruyere, C. 27

C

Carey, A.E. 12

Cashman, K. 6

Collins, L 9

Corbett, E. 14

Couvin, B. 27

Coveney, S. 28

Craven, K. 19

Curran, M.J. 13

D

Daly, E. 16

Daly, J.S. 15

Doran, A. 28

Dornan, T. 20

Doyle, E. 18, 28

Duncan, N. 15

E

Ess, C. 29

F

Falk, D. 20

Fiaschi, S. 29

Foreman, A. 8

G

Geever, M. 29

H

Heptinstall, E.A. 30

Hogg, C. 30

Hughes, M. 30

I

Irwin, S. 31

K

Kiyan, D. 18, 31

Koch, H.A. 10

Kovács, E.B. 11

L

Latimer, B. 31

Lemon, K. 32

Le Pape, F. 13

Lowney, B. 15

Lyons, W.B. 32

M

Malone-Leigh, J. 32

Mather, B. 18

Mathew, S. 21

McCarthy, O. 12, 33

McClenaghan, S.H. 8

McConnell, B. 33

McCormack, T. 9

Meloni, M.A. 33

Menuge, J.F, 8

Möllhoff, M. 34

Monchal, V. 34

Monteys, X. 34

Murphy, J.B. 17

Murray, J. 12

O

O’Connell, Y. 21

O’Donnell, E. 10

Ó Gogáin, A. 35

O’Leary, D. 9

Oliveira, I.L. Macedo Cruz de 35

O’Reilly, L. 13

P

Papageorgiou, F. 17

Pierce, C. 35

Pracht, M. 36

Premrov, A. 36, 37

Q

Quirke, R. 37

R

Raine, R. 38

Rateau, R. 38

Ruhl, M. 11

S

Sanders, I. 14

Scanlon, E. 38

Scanlon, R. 22

Scroxton, N. 14

Silva, R.L. 39

Simms, M.J. 20

Smith, D.F. 39

Smith, L. 39

Strachan, R. 40

Summers, G. 40

Symons, J. 41

T

Tierney, C. 41

Tomar, G. 20

Torremans, K. 10

W

Watson, R.A. 19

Wheeler, S. 16

Williams, M. 6

X

Xu, W. 16

Xu, Y. 21

Z

Zhou, L. 41

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