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Earth Science Conservation Review
| Glen-Coolcran Townlands stream | Fermanagh |
| Site number: | 244 | File Number: | H35 |
| ESCC: | EO | ||
| Locality Type: | Stream section | Status: | ASSI |
| Grid Reference: | H348509 Centroid | ||
| Google maps: | 54.40596,-7.46408 | ||
| County: | Fermanagh | Council area: | Fermanagh & Omagh District Council |
| Period: | Carboniferous | ||
| Stages: | Visean | ||
| Lithostrat: | Coolcran Conglomerate Member, Kilskeery Group, Topped Mountain Sandstone Formation | ||
| Site Description | |
|---|---|
| Highlights: | |
Some 200m below the top of the Topped Mountain Formation are interbedded sandstones and conglomerates of the Coolcran Conglomerate Member which are indentical to the lithologies that occur higher in the sequence, as the Ballyreagh Conglomerate Formation. The stratotype section is unusual in that it contains a thin mudstone with miospores. | |
| Description: | |
The stratotype stream section of the Coolcran Member is located 2km south of the summit of Brougher Mountain. The sequence is exposed over 120m of river bed in a deeply incised stream which cascades over a series of small waterfalls. Strata are inclined to the NW at between 20-28 deg. At the base of the member, which is exposed beneath the road bridge (H347 508) at the south end of the section, is a 3m thick conglomerate bed containing blocks of volcanic lava up to 0.12m diameter. The succeeding 30m of strata are more or less completely exposed in the stream and consist of massive to flaggy, medium to coarse-grained greyish-red sandstones with thin layers of pebbles and conglomerates, up to 1m thick. The miospore assemblage recorded from the Coolcran Conglomerate Member was recovered from 0.07m of green micaceous silty shale, interbedded with the conglomerates and sandstones, in the lowest part of the member. Miospores recorded are indicative of a late Vis‚an age and an assignment to the NM or VF Zones (late Asbian- Brigantian stages). They include the following species: Calamospora parva Densosporites sp. D. anulatus Discernisporites sp. Granulatisporites granulatus Knoxisporites stephanephorus Leiotriletes adnatus Lycospora pusilla Raistrickia sp. Retusotriletes sp. Vallatisporites ciliaris | |
| Interpretation: | |
The sedimentary rocks that constitute the three formations of the Kilskeery Group record the history of punctuated subsidence of a non-marine basin. Gradual and sustained subsidence of this basin in late Asbian times accommodated the 1000m of sand-dominated sediments of the Topped Mountain Formation. Accelerated uplift in the early Brigantian, of the southern margin of this northern land area led to increased erosion and southward progradation of alluvial fans, in the process depositing largely coarse-grained and conglomeratic debris of the Ballyreagh Formation. A gradual diminution in the rate of uplift of the metamorphic and Lower Palaeozic massif in the late Brigantian led to its eventual burial by the distal alluvial plain and playa-lake sediments of the Ballinamallard Mudstone Formation in the south, and possibly by the Greenan Sandstone in the north (Mitchell & Owens, 1990). This situation persisted into Pendleian times at which point the sedimentary record ends. | |
| Notes: | |
For information on other sites in Subarea-4 see; Key Site 1177 - Subarea-4; Fintona Block. | |
| Keywords | |
|---|---|
| Rocks: | Conglomerate, Sand, Sandstone |
| Fossil Groups: | Miospore |
| Fossil List: | Lycospora pusilla |
| Access | |
|---|---|
| Approach: | 2km south of the summit of Brougher Mountain. |
| References (1) | |||
|---|---|---|---|
| Blieck, A., 1991. Reappraisal of the heterostracans (agnathan vertebrates ) of Northern Ireland. Irish Journal of Earth Sciences, vol. 11 pt. 1, pp.65-69. | |||
| Map(s): | See 1:50,000 O.S. Sheet 18 (Enniskillen); GSNI (1982) 1:50,000 Solid Geology of Sheet 45 (Enniskillen). | ||
| Record type: | ESCR report | ||
| Entered by: | Doughty, P.J. | ||
| Last updated: | 6 Jun 2005 | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Glen-Coolcran Townlands stream, County Fermanagh, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=244. Accessed on 2026-11-06. |
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