Earth Science Conservation Review
| Crockfadda - site of local interest | Fermanagh, Tyrone |
| Site Type: | Inland exposure, Pit |
| Site Status: | local interest |
| Council area: | Omagh District Council |
| Grid Reference: | H346544,H390565 |
| Google maps: | 54.43742,-7.46675 |
| Rocks | |
|---|---|
| Rock Age: | Quaternary |
| Rock Type: | Gravel, Sand |
| Interest | |
| Other interest: | Glacio-fluvial sediment, meltwater channel, moraine ridge, outwash terrace, glacial |
Description:
This area, extending for 5km from Crockalusky [H346 544] to Crocknafarbrague [H390 565], is characterised by aligned moraine ridges and flat, dissected outwash surfaces. Ridges are generally aligned northeast or east to southwest or west, parallel to the Fintona Hills to the south. Ridges are up to 900m long, 300m wide and 20m high and are often closely spaced (50m), separated by deeply incised and narrow meltwater channels. Ridges are also related to feeder eskers (transferring material from west to east), kettleholes, proximity of bedrock surfaces and intervening localised outwash spreads. There are two main exposures in the outwash and ridge sediments:
1. Meencrim Pit [H377 559] is a mostly disused sand pit and shows a range of rhythmically-bedded, well-sorted, fine-grained sediments with some glaciotectonic deformation. This exposure records low energy subaqueous sedimentation influenced by local current activity and seasonal meltwater events.
2. Cocknaboortan [H372 551] - this exposure is 25m long and 5m high and is characterised by dipping units (40-60cm thick) of sorted clast- and matrix-supported massive and occasionally normally-graded beds composed of sand to pebble gravels (<15cm across). This sediment is interpreted to reflect an ice-marginal environment affected by ice melt-out and post-depositional water migration processes.
1. Meencrim Pit [H377 559] is a mostly disused sand pit and shows a range of rhythmically-bedded, well-sorted, fine-grained sediments with some glaciotectonic deformation. This exposure records low energy subaqueous sedimentation influenced by local current activity and seasonal meltwater events.
2. Cocknaboortan [H372 551] - this exposure is 25m long and 5m high and is characterised by dipping units (40-60cm thick) of sorted clast- and matrix-supported massive and occasionally normally-graded beds composed of sand to pebble gravels (<15cm across). This sediment is interpreted to reflect an ice-marginal environment affected by ice melt-out and post-depositional water migration processes.
| Enlander, I., Dempster, M. & Doughty, P., 2024. Crockfadda - site of local interest, County Fermanagh, Tyrone, site summary. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/summary.php?item=718. Accessed on 2024-12-26 |
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