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Earth Science Conservation Review
| Rushindoo Townland quarry | Fermanagh |
| Site number: | 223 | File Number: | H17 |
| ESCC: | EA | ||
| Locality Type: | Quarry (working) | Status: | ESCR |
| Grid Reference: | H15927195 Centroid | ||
| Google maps: | 54.59555,-7.75399 | ||
| County: | Fermanagh | Council area: | Fermanagh & Omagh District Council |
| Period: | Carboniferous | ||
| Stages: | Visean | ||
| Lithostrat: | Bin Mountain Sandstone Formation, Rushindoo Oolite Member, Tyrone Group | ||
| Site Description | |
|---|---|
| Highlights: | |
The stratotype quarry exposes the maximum thickness of the Rushindoo Oolite. | |
| Description: | |
The stratotype quarry of the Rushindoo Oolite Member is located near the northwestern edge of Rushindoo Townland 250m east of the Termon Bridge and 8.2km NNW of Kesh. The limestone is exposed in two faces, the longest exposing about 5m of rock and is located on the north side of the farmroad. Strata in the quarry are inclined southwards at about 15o and about 3.5m of strata are exposed. The full extent of the outcrop of the Rushindoo Oolite is not known because it straddles the international border with the Republic of Ireland where it has not been mapped in detail. In N. Ireland its outcrop length is about 1km and eastwards passes laterally into sandstones and sandy limestones that are typical of the Bin Mountain Sandstone Formation. In the stratotype quarry the rocks consist of pale to medium fawn-grey, medium-grained oolites, sandy oolites and thin beds of very calcareous sandstone. Wavy cross-bedding and parallel laminations are common. Bioclasts are all fragmented and both they, and small limestone intraclasts are invariably micritised. Neither the upper nor lower contact of the member is exposed but it is doubtful that its total thickness would exceed the 5 or 6m attributed to the formation in the Giant's Grave section. | |
| Interpretation: | |
The Bin Mountain Sandstone Formation was clearly deposited in a nearshore, shallow water marine environment. At the Binnawooda section (Key Site 220) the sediments at the contact between the Claragh and Bin Mountain formations were deposited in an environment that changed rapidly but continuously from terrestrial and fluvial conditions, to supratidal and peritidal conditions (the limestone beds between the two formations) and finally, in the Bin Mountain Sandstone, into a shallow water shoreline to sandflat environment. Interbedded within this formation are thin beds of bird's eye micrite, typical of peritidal facies indicating transitory fluctuations in sea-level. The dominant environment was however shallow water marine with a persistent, but clearly localised near-shore input of large quantities of sand and, less commonly of coarse pebble debris. The concentration of the quartz pebbles in the Tullyard Member occurred most probably in a proximal location near the source of the debris, for example at the mouth of a river draining a land area of higher ground. Whatever the source of these pebbles their consistent roundness indicates a prolonged history of sorting and reworking, in the process smoothing all angularities. This may have been a feature of the original source of the pebbles or may have occurred in a very shallow water beach environment. The abundance of Pelecypodichnos and Skolithos burrows is indicative of a shallow water, littoral, environment. South and southwestwards from the Bin Mountain area, the formation thins dramatically and passes laterally, in lower levels, into peritidal carbonates of the Termon River Limestone Formation. Sandy oolites and limestones and sandstones containing individual isolated ooliths abound in the stratotype section and throughout the outcrop of the Bin Mountain Sandstone Formation. It is hardly surprising therefore to find a section in this outcrop where relatively sand-free oolitic limestones are the dominant lithology. The accepted mode of formation of oolites is in shallow wave-agitated water. Successive concentric layers of calcium carbonate are deposited around a nucleus such as a shell fragment or a quartz-sand grain. Oolitic limestones, such as the Rushindoo Member, are composed almost exclusively of ooliths and are characteristically shale-free. | |
| Conclusions: | |
The Bin Mountain Sandstone Formation consists of shallow water sandstones, conglomerates, oolitic limestones and sandy limestones that were deposited in a near shore location. | |
| Notes: | |
For information on other sites in Subarea-3 see; Key Site 1176 - Subarea-3; Kesh-Omagh. | |
| Keywords | |
|---|---|
| Rocks: | Limestone, Oolitic limestone, Sand, Sandstone |
| Relations: | Marine sediments |
| Measurements | |||||
|---|---|---|---|---|---|
| Length: | 5 m+ | Width: | Height: | ||
| Depth: | Area: | ||||
| Access | |
|---|---|
| Approach: | The stratotype quarry of the Rushindoo Oolite Member is located near the northwestern edge of Rushindoo Townland 250m east of the Termon Bridge and 8.2km NNW of Kesh. |
| Map(s): | See 1:50,000 O.S. Sheet 12 (Strabane). | ||
| Record type: | ESCR report | ||
| Entered by: | Doughty, P.J. | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Rushindoo Townland quarry, County Fermanagh, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=223. Accessed on 2026-11-08. |
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