Earth Science Conservation Review
| Coolesker - site of local interest | Tyrone |
| Site Type: | Inland exposure |
| Site Status: | local interest |
| Council area: | Omagh District Council |
| Grid Reference: | H512650,H508669,H531751 |
| Google maps: | 54.53123,-7.20912 |
| Rocks | |
|---|---|
| Rock Age: | Quaternary |
| Rock Type: | Diamict, Gravel, Sand |
| Interest | |
| Other interest: | Glacial deposit, esker, outwash, glacial |
Description:
This area extends for 12km from south of Beragh to Lough Macrory and is characterised by elongate and sinuous esker ridges, associated with broad sand and gravel spreads, which overlie northwest-southeast orientated diamict ridges. Esker ridges are up to 1km long, 5-10m high and 10-40m wide and individual ridge fragments are separated by areas (100-500m wide) of non-deposition and/or erosion. Esker crest profiles are flat or slightly undulatory and ridges are generally bifurcated. There are no significant exposures.
These ridges generally form a rectilinear or lattice pattern. There are also major differences in landscape morphology. Eskers trending southwest-northeast feed into ridges, interpreted as moraines, which are aligned north-south. Beragh Hill [H536 662] is a flat-topped sand and gravel landform and is directly associated with feeder eskers from the southwest. The hill may represent a proglacial delta related to glacial lake development between an eastern ice margin and the Fintona Hills to the south and it may account for the wider development of north-south orientated ridges (ice-marginal moraines) and associated feeder eskers at Gortnaclare. A similar scenario can be applied to the development of flat sand and gravel surfaces at Mullaghslin [H564 732] and Drumnakilly [H538 732] which have been fed by the Seefin and Cloghfin eskers respectively. This interpretation may also account for the rectilinear ridge pattern and relate to evidence elsewhere for regional western and southwestern ice retreat. These glacial lakes may have been impounded while Lough Neagh Basin ice still occupied the Pomeroy-Sixmilecross valley. Enclosed peatland and disordered sand and gravel hummocks in the areas between feeder esker ridges may reflect ice stagnation.
These ridges generally form a rectilinear or lattice pattern. There are also major differences in landscape morphology. Eskers trending southwest-northeast feed into ridges, interpreted as moraines, which are aligned north-south. Beragh Hill [H536 662] is a flat-topped sand and gravel landform and is directly associated with feeder eskers from the southwest. The hill may represent a proglacial delta related to glacial lake development between an eastern ice margin and the Fintona Hills to the south and it may account for the wider development of north-south orientated ridges (ice-marginal moraines) and associated feeder eskers at Gortnaclare. A similar scenario can be applied to the development of flat sand and gravel surfaces at Mullaghslin [H564 732] and Drumnakilly [H538 732] which have been fed by the Seefin and Cloghfin eskers respectively. This interpretation may also account for the rectilinear ridge pattern and relate to evidence elsewhere for regional western and southwestern ice retreat. These glacial lakes may have been impounded while Lough Neagh Basin ice still occupied the Pomeroy-Sixmilecross valley. Enclosed peatland and disordered sand and gravel hummocks in the areas between feeder esker ridges may reflect ice stagnation.
| Enlander, I., Dempster, M. & Doughty, P., 2024. Coolesker - site of local interest, County Tyrone, site summary. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/summary.php?item=714. Accessed on 2024-12-26 |
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