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Earth Science Conservation Review
| Dungoran - site of local interest | Tyrone |
| Site number: | 726 | ||
| Locality Type: | Inland exposure | Status: | local interest |
| Grid Reference: | H403565,H445595 End(s) of linear site | ||
| Google maps: | 54.45586,-7.37863 | ||
| County: | Tyrone | Council area: | Fermanagh & Omagh District Council |
| Period: | Quaternary | ||
| Site Description | |
|---|---|
| Highlights: | |
This area extends for 5.5km from Crockroe [H403 565] to Syonfin [H445 595] 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. | |
| Description: | |
This area extends for 5.5km from Crockroe [H403 565] to Syonfin [H445 595] 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: 1. Crockroe - this exposure, 12m long and <3m high, shows a stacked succession of gravely facies with occasional sandy interbeds. Gravel beds are massive to normally-graded, are both clast- and matrix-supported, and are often separated by erosional contacts. Thicker beds are generally clast-supported and composed of poorly-sorted subrounded cobbles and boulders. These clasts often show a (p) imbrication parallel to the ridge long axis, and vertical stacking. 2. Syonfin - a 50m long, <11m high exposure of interbedded sand and gravel units (20-60cm thick) with discontinuous (up to 6m), well-sorted sandy interbeds (10-30cm thick). These sediments are overlain by a thin (1-2m) diamict carapace. Gravel beds are generally tabular, massive or cross-bedded, and often channelised 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. | |
| Importance: | |
The site is scientifically important as it contains a good example of a kame-esker-outwash system. | |
| Interpretation: | |
The Crockroe 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. This esker occurs within a bedrock-cut channel which may be related to subglacial meltwater. The Syonfin exposure records the 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 channelisation. 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 channelised into this depocentre through a marginal drainage system from an ice mass some distance away. From this regional evidence, channelisation may have occurred between stagnant ice blocks or associated with the marginal kame terraces at Dungoran. | |
| Notes: | |
See also ESCR Key Site 496 - Fintona Hills Complex - Dungoran kame-esker-outwash system [Sand and Gravel Landscapes Block]. | |
| Keywords | |
|---|---|
| Rocks: | Diamict, Gravel, Sand |
| Relations: | Subaqueous outwash |
| Geomorph: | esker, kame terrace, outwash, subglacial sediment |
| Paleoenv: | glacial |
| Measurements | |||||
|---|---|---|---|---|---|
| Length: | 5.5km | Width: | Height: | ||
| Depth: | Area: | ||||
| Access | |
|---|---|
| Approach: | This site is located between Crockroe and Syonfin. |
| Uses | |
| Educ. Level: | The site is of educational value to researchers and students of glaciology. |
| Record type: | SLNCI Report | ||
| Entered by: | E M Porter | ||
| Last updated: | 09/10/03 | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Dungoran - site of local interest, County Tyrone, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=726. Accessed on 2026-11-06. |
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