Remapping the Moffat Shale Group using Tellus geophysics
The Moffat Shale Group is a deep marine mudstone sequence that forms the base of successive thrust slices of metasedimentary rocks in the Longford – Down geological terrane. Detailed mapping of the distribution of the shales is relevant to mineral prospectivity and understanding the closure history of Iapetus at the Laurentian margin. Moffat shale horizons produce a strong conductivity signal in the Tellus and Tellus Border airborne geophysical survey data. Recent work in the Geological Survey of Ireland combined interpretation of the airborne electromagnetic data with re-examination of 19th century 6″ field sheets and core drilling to re-map the Moffat shales in Co. Monaghan. Drilling of a blind anomaly proved the efficacy of the method. The re-mapping has identified a revised distribution of Moffat shales and therefore of the tract-bounding faults, including identifying a new structural panel.
Unravelling ice sheet history using Tellus soil geochemical data
Investigator(s): Dr Paul Dunlop, Innovation Ulster Ltd; Dr Michael Dempster, University of Ulster.
Funder: EU INTERREG IVA -funded Tellus Border project
Ice sheets are an integral part of the global climate system and investigating their behaviour provides crucial information on how they respond to and drive climatic changes. Past and palaeo-ice sheets have left a rich geological record, which can be used to reconstruct former ice sheet events through glacial/deglacial cycles. The north of Ireland has a diverse geology and a complex glacial history. This study undertook the first regional-scale investigation of geochemistry in the northern sector of the Irish Ice Sheet, in order to inform understanding of regional ice flow patterns. Principal components analysis showed a strong geochemical link between till and local bedrock, with rapid geochemical changes observed across lithological boundaries, indicating that transport distances of subglacial material were low. The work concluded that the majority of till deposits in the survey area have been locally derived, meaning that the rate of subglacial transport in this sector of the Irish Ice Sheet was low and that there were low rates of evacuation of subglacial debris to the ice margins.
Peer reviewed publication