Mapping our earth resources

The important task of mapping, whether onshore or offshore, is essential to support the range of services that GSI provides. It provides a baseline for monitoring and modelling activity and it confirms (or “ground-truths”) the results of remotely-sensed information.

“Mapping...is essential to support...(GSI) Services...

2005 was the final year of the Irish National Seabed Survey (INSS). With Zone 3 (deep water) already fully surveyed, surveys during this year brought the coverage in shallow water Zone 2 (50-200m water depths) to 30%. The ship-based surveys, carried out in partnership with the Marine Institute, continued in the Donegal Bay area using the RV Celtic Explorer. A total of 28,263 line km of data was collected in four survey legs and in addition a number of seabed sediment samples were collected. In addition the RV Celtic Voyager spent 45 days surveying off the east and south coasts, including data acquisition for the IMAGIN project supported by INTERREG and led by the Coastal and Marine Resource Centre of University College Cork.

Mulroy Bay, County Donegal, is an inlet whose bathymetry was imperfectly known and whose potential for shipping has not been fully achieved. In order to improve the information available GSI in conjunction with Donegal County Council contracted an airborne LIDAR survey of the bay. Completed by the Tenix Lads Corporation of Australia, the resulting survey provides a high quality profile of the seabed of this complex bay. This provides additional, although still limited, coverage in Zone 1 (less than 50m water depth). Following the successful completion of INSS, the Government has announced approval of a successor programme (see “Sustainable offshore management”).

Recent progress in land-based surveying is covered in the panels accompanying this chapter. They were supported by an extensive drilling programme whose results are summarised on opposite page. 156 holes were drilled to an aggregate depth of 2,225 metres.

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Borehole No:

County

Location

Drilling Method

Total Depth (m)

Mapping Sections

GSI/05/1

Monaghan

Gortmore Sth

Coring

39.0

Bedrock

GSI/05/2

Monaghan

Barratitoppy

Coring

161.0

Bedrock

GSI/05/3-69

Louth

Various

Flight Augering

676.0

Quaternary

GSI/05/70-83

Westmeath

South

Flight Augering

80.0

Quaternary

GSI/05/84

Offaly

North

Flight Augering

9.0

Quaternary

GSI/05/85-87

Westmeath

South

Flight Augering

19.0

Quaternary

GSI/05/88-114

Offaly

North

Flight Augering

288.0

Quaternary

GSI/05/115-117

Kildare

North

Flight Augering

23.0

Quaternary

GSI/05/118

Laois

North East

Flight Augering

7.0

Quaternary

GSI/05/119-125

Kildare

North

Flight Augering

62.0

Quaternary

GSI/05/126

Carlow

South

Flight Augering

10.0

Quaternary

GSI/05/127-128

Kildare

North

Flight Augering

22.0

Quaternary

GSI/05/129-136

Carlow

South

Flight Augering

47.0

Quaternary

GSI/05/137

Laois

North Central

Flight Augering

5.0

Quaternary

GSI/05/138-140

Carlow

South

Flight Augering

28.0

Quaternary

GSI/05/141

Wicklow

West

Flight Augering

8.0

Quaternary

GSI/05/142-147

Kildare

North

Flight Augering

43.0

Quaternary

GSI/05/148-149

Dublin

Loughlinstown

Flight Augering

26.0

Quaternary

GSI/05/148A

Dublin

Loughlinstown

Coring

33.0

Quaternary

GSI/05/149A

Dublin

Bray

Coring

31.0

Quaternary

GSI/05/150

Monaghan

Scotstown

Coring

60.5

Bedrock

GSI/05/151

Monaghan

Shanroe

Coring

150.5

Bedrock

GSI/05/152

Galway

Cappan Raheen

Coring

251.0

Bedrock

GSI/05/153

Galway

Kilcreest

Coring

106.0

Bedrock

GSI/05/154

Galway

Carrowmuna

Coring

100.0

Bedrock



Sustainable Offshore Management

Ireland since 1999 has developed a world-class reputation for seabed mapping through the success of the Irish National Seabed Survey, which has already mapped 87% of the Irish seabed area. GSI with its strategic partner, the Marine Institute, and others has led the development of methodologies, human capability and physical infrastructure.

Building on this success, the Government has approved a follow-on strategy, Integrated Mapping for the Sustainable Development of Ireland’s Marine Resource (INFOMAR). The focus of this new programme, which will be a joint venture between GSI and the Marine Institute, will be on the near-shore environment - an area subject to significant development and environmental regulation. An extensive stakeholder process has identified priority areas for mapping: the resulting 26 priority bays and three coastal areas are outlined on the accompanying map.

The programme has three major components:

  • Data acquisition, management and interpretation;
  • Data exchange and interpetation - to establish inter-agency data exchange;
  • Value added exploitation - to deliver demand-driven opportunities to create added value.


INFOMAR is set to deliver significant national benefits. In addition to the value added to specific stakeholders, additional benefits arise from marine data integration and interpretation, increased national research profile and commercial services and contracts.

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New Maps for Old!
The first edition of the Geological Map of Ireland was completed in the 1890s based on almost 50 years of intensive mapping on the scale of 1:10,560 and subsequent publication at 1:63,360. This set provided remarkable value for money, being the main source of geological mapping for a full century. During the 1990s a major initiative was undertaken to rapidly update these maps, based on compiling information from all available sources, in order to make the insights of the intervening decades available to map users. Based on the scale of 1:100,000, all the maps have now been published and only one accompanying booklet (for Sheet 11) remains to be printed.

1:100,000 scale map
1:50,000 scale map

Already GSI has completed a draft pilot for a new series of bedrock maps. What was the need to commence the job once more? The new maps will be on a scale of 1:50,000 and will include specific point information, such as boreholes, outcrops and quarries. This will allow the map user to form a judgment on the reliability of the map, or a particular part of it. The user will also, because the map will be digital, be able to interrogate more detailed information based on associated databases. A whole new spectrum of information will be available to users. The new map series also recognizes the uncertainties in many of the 1:100,000 map series, especially where the geology was either unusually complex or poorly exposed. Such areas will be marked out for special attention in this mapping programme wherever a specific priority has been established.

Ice sheets leave a heritage

Mapping over adjoining areas of Counties Westmeath and Offaly, published in 2005*, depicts patterns of sediments that were formed during glacial (Ice Age) and post-glacial times. They make up a landscape that typifies almost the entire Shannon River basin. Pride of place must go to those deep green coloured linear ridges on the map, which have both southeasterly and east northeasterly trends that converge about 5km east of Kilbeggan. These are esker ridges formed by meltwater rivers under or immediately proximal to ice sheets. Their pattern reflects the fact that the ice sheet comprised two ice domes which merged at the latitude of Kilbeggan, with the meltwaters from both domes meeting here. Indeed some of the eskers shown, part of Eiscir Riada, marked an ancient boundary between two halves of Ireland, Leath Choinn to the north and Leath Mhogha to the south. These ridges are dominant features of the midland landscape, they formed a critical part of its communications network over thousands of years and remain an important component of our natural heritage. Of course their sands and gravels are also important sources of aggregate which support construction and road building.

During 2005 Quaternary mapping on a 1:50,000 scale was completed in eastern County Westmeath and County Louth in a project jointly funded by Kilsaran Concrete Products Ltd and GSI. In addition the digitizing of archival Quaternary geological data, albeit of poor quality, for 50% of County Tipperary was completed at the year end. A number of successful mapping projects were completed in recent times in East Leinster (Counties Carlow, Kildare, Offaly, Westmeath and Wicklow) and a programme of 80 boreholes was undertaken to facilitate production of a seamless regional map (through filling small gaps and reconciling boundaries)

Sheet 48
*Sheet 48, 1:50,000 scale GSI Quaternary Geology Map

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