ESCR - Fintona Hills Complex - Dungoran kame-esker-outwash system

Earth Science Conservation Review

Summary Full report
Fintona Hills Complex - Dungoran kame-esker-outwash system	Fermanagh, Tyrone

Site number:	496
ESCC:	IS
Locality Type:	Inland exposure	Status:	TBC
Grid Reference:	H403565,H445595 End(s) of linear site, Not Entered
Google maps:	54.45586,-7.37863
County:	Fermanagh, Tyrone	Council area:	Fermanagh & Omagh District Council
Period:	Quaternary

Site Description
Description:
This area extends from Crockroe (H403565) to Syonfin (H445595) (5.5km) and is characterised by undulatory sand and gravel ridges, generally aligned northeast-southwest. The sand and gravel limit is sharply disposed against the bedrock of the Fintona Hills to the south. Elsewhere in this area, ridges are more sharply defined, bifurcated and associated with enclosed depressions. There are two main exposures. The Crockroe exposure occurs in a northeast-southwest oriented ridge. Facies description This exposure (12m long and <3m high) shows a stacked succession of gravelly facies with occasional sandy interbeds. Gravel beds (0.5-0.8m thick) are massive to normally-graded and both clast- and matrix-supported, and often separated by erosional contacts. Thicker beds are generally clast-supported and composed of poorly-sorted subrounded ORS cobbles and boulders (<50cm diameter). These clasts often show a(p) imbrication parallel to the ridge long axis, and vertical stacking. Cobbles and boulders often form discontinuous lags and openwork clusters (0.3 x 0.4m dimensions). Massive granule to pebble (<10cm diameter) interbeds (0.3-0.4m thick) are generally laterally continuous (to 4m), better sorted, and have fairly sharp, welded contacts. Deformed dm-scale sorted coarse sand stringers (<0.5m long) also occur. Clast imbrication indicates flow was southwest to northeast. Facies interpretation This exposure is interpreted as a subglacial esker. Stacked and variably interbedded poorly sorted gravels separated by sandy stringers may relate to periodic flow pulses within the esker depositing a variety of energy-dependent sediments (Brennand, 1994). Basal lags and erosional surfaces attest to high energy sediment stripping at the initiation of the flow pulse. Clast suspension settling (giving a(p) fabrics) may reflect high dispersive pressures generated by the matrix component (Hampton, 1975). Deformed, sorted sand stringers may result from waning flow sediment settling or under current activity. Clasts are of local provenance and a southwest-northeast flow direction is consistent with other regional transport indicators. Also, this esker occurs within a bedrock-cut channel (cf. Brennand and Sharpe, 1993) which may be related to subglacial meltwater activity. The Syonfin pit, 2km south of Fintona, is cut into an outwash surface and shows one main exposure face. Facies description This exposure (50m long and <11m high) is composed of interbedded sand and gravel units (0.2-0.6m thick) with discontinuous (to 6m) well-sorted sandy interbeds (0.1-0.3m thick). These sediments are overlain by a thin (1-2m) diamict carapace. Gravel beds are generally tabular, massive or cross-bedded, and often channelized and interbedded with sandy drapes, stringers and minor faults. Sand beds are generally massive to well-laminated, well-sorted and often overlain by discontinuous clay drapes. Major sand and gravel facies are usually separated by sharp erosional surfaces. Sand facies are a minor component (10%), and occur mainly at the base of the exposure. These facies fine upwards and change from massive to laminated, with ripple beds that climb to 070§. The bulk of the exposure (90%) is composed of stacked beds of massive, well-sorted and cross-bedded pebbles (<10cm diameter). A minor part of the gravel component (15%) is composed of erratics derived from the Tyrone Igneous Complex. Cross-bed dip is generally towards 060§-090§. Occasional a(t) clast imbrication dips to 230§-240§. Small compressional faults towards the top of the exposure strike 050§-230§. Facies interpretation This exposure records deposition of subaqueous outwash sediments in a proglacial setting. Variations in flow characteristics, energy and ice proximity is inferred from sand and gravel interbeds, erosional surfaces and channelization. Consistent palaeoflow direction may indicate a well-defined input location that did not change dramatically over time. This may be related to a static ice margin, but it is more likely that meltwater was channelled into this depocentre through a marginal drainage system from an ice mass some distance (km scale) away. From this regional evidence, channelization may have occurred between stagnant ice blocks or associated with the marginal kame terraces at Dungoran (H437581). Clay drape development also favours a more distal and episodic water source. Push fault orientation may be related to ice activity in the Glennamuck valley 2km to the south. This indicates that more than one ice margin may have contributed to the moraine-outwash system. The presence of a diamict carapace may reflect resedimentation from unstable sediments upslope.
Notes:
For site specific information on other sites within the Fintona Hills Complex see the following sites: Key Site 494 - Fintona Hills Complex - Ballinamallard Esker Key Site 495 - Fintona Hills Complex - Crockfadda outwash-moraine system Key Site 497 - Fintona Hills Complex - Dromore outwash-moraine system Key Site 498 - Fintona Hills Complex - Newtownsaville Esker For overview information and references on the Fintona Hills Complex see the following site: Key Site 484 - Fintona Hills Complex - Overview For general information and references on the sand and gravel landscapes of N. Ireland, and for directions to other regional sand and gravel sites, see the following site: Key Site 439 - Introduction to the Sand and Gravel Landscapes of N. Ireland This site is also a Site of Local Nature Conservation Importance. See Key Site 726 - Dungoran.

Keywords
Rocks:	Gravel, Sand
Relations:	Glacial deposit
Geomorph:	esker, kame terrace, outwash


Record type:	ESCR report
Entered by:	E M Porter
Last updated:	6 Jun 2005

Enlander, I., Dempster, M. & Doughty, P., 2026. Fintona Hills Complex - Dungoran kame-esker-outwash system, County Fermanagh, Tyrone, site details. [In] Earth Science Conservation Review.
https://www.habitas.org.uk/escr/site.php?item=496. Accessed on 2026-11-06.