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Earth Science Conservation Review
| Lurgan River, Mullylusty Townland | Fermanagh |
| Site number: | 198 | File Number: | H04 |
| ESCC: | EO | ||
| Locality Type: | Stream section | Status: | local interest |
| Grid Reference: | H087413 Centroid | ||
| Google maps: | 54.32084,-7.86628 | ||
| County: | Fermanagh | Council area: | Fermanagh & Omagh District Council |
| Period: | Carboniferous | ||
| Stages: | Asbian, Visean | ||
| Lithostrat: | Glenade Sandstone Formation, Meenymore Formation | ||
| Site Description | |
|---|---|
| Highlights: | |
An almost complete section of the Meenymore Formation is exposed in the Lurgan River and in cliffs forming the east wall of its valley in Mullylusty Townland. An estimated 44m of strata are exposed, out of a total thickness of about 48m for the formation. The contact with the succeeding Glenade Sandstone Formation is exposed. | |
| Description: | |
The Lurgan River section of the Meenymore Formation, in Mullylusty Townland, is located just over 3km north-northeast of Belcoo, and strata crop out over 200m of the river bed and valley sides. At the southern end of the section (H0872 4123) and (H0877 4128) are isolated exposures of alternating limestones and fossiliferous shaley mudstones of the Carn Limestone Member, the top unit of the Dartry Limestone Formation. The precise contact between the highest shales of this unit and succeeding laminated algal carbonates and grey blocky unfossiliferous mudstones, in the west bank of the river, of the Meenymore Formation is concealed. The lowest part of the formation, some 17m thick, is exposed just north of these lithologies and comprises two sandstone waterfalls in the river, the northern one being overlain in the east bank by 6m of mudstones with thin limestones which are themselves succeeded by 9.5m of sandstones and thin mudstones further north in the east bank. The occurrence of micrite coated goniatites and most unusually, of liquid hydrocarbons (oil) in calcite-lined vugs occurs near the base of the lower section of the formation. The top of the Meenymore Formation and the contact with the orange-stained, basal conglomerate of the Glenade Sandstone Formation is exposed in the 4m high waterfall and plunge pool located at the north end (H0875 4145) of this section. The top beds of the Meenymore Formation here consist of 0.76m of contorted laminated algal limestones. | |
| Interpretation: | |
The association of sedimentary structures that occur in various lithologies in the Lurgan River section substantiate the conception of sediment deposition in the intertidal zone which was prone to flooding both by fresh, sediment-laden, water from adjacent higher ground and by the spread of marine conditions. Maximum flooding of the sea was transitory but still introduced a marine fauna, in particular goniatites, onto the flat tidal zone. Reworking of ammonoid shells, in particular, occur in carbonate rich, supratidal waters as evidenced by their coating of algal (?) micrite and by their association with laminated algal carbonates. Periodic emergence of the sediment surface led to desiccation and the formation of polygonal cracks on mudstones, limestones and sandstones. The contortions and folding affecting the laminated carbonates located at the top of the formation in the Lurgan River section are considered to reflect the incompetent nature of the relatively plastic, layered sediment, during early diagenesis when contemporaneous seismic activity may have been the cause of the contortions. | |
| Conclusions: | |
The Lurgan River section through the Meenymore Formation is undoubtedly one of the most complete in Co. Fermanagh and in Subarea-1. Lithologies present are quite typical of this formation and support the concept of deposition of the sediments in a shallow water, intertidal environment. | |
| Notes: | |
For information on other sites in Subarea-1 see; Key Site 1174 - Subarea-1; Derrygonnelly-Marble Arch-Cuilcagh. | |
| Keywords | |
|---|---|
| Rocks: | Limestone, Mudstone |
| Fossil Groups: | Goniatite |
| Access | |
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| Approach: | 3km NNE of Belcoo. |
| References (7) | |||
|---|---|---|---|
| Brandon, A., 1968. The geology of the Carboniferous strata (Visean - Namurian) in parts of counties Leitrim and Cavan (Ph.D. thesis). (Thesis) University of Southampton. | |||
| Brandon, A., 1972. The upper Visean and Namurian shales of the Doagh Outlier, County Fermanagh, Northern Ireland. Irish Naturalists Journal, vol. 17, pp.159-170. | |||
| Brandon, A., 1977. The Meenymore Formation - an extensive intertidal evaporitic formation in the Upper Visean (B2) of north-west Ireland. Report of the Institute of Geological Sciences, numb. 77/23, pp.1-14. | |||
| Gardiner, B.G. & Mason, T.R., 1974. On the occurrence of the palaeoniscid fish Elonichthys serratus in the Visean of County Fermanagh, with a note on the Enniskillen and Egerton collections. Proceedings of the Royal Irish Academy, vol. 74(B), pp.31-36. | |||
| Oswald, D.H., 1955. The Carboniferous Rocks between the Ox Mountains and Donegal Bay. Journal of the Geological Society of London, vol. 111, pp.167-186. | |||
| Riley, N.J., 1993. Dinantian (Lower Carboniferous) biostratigraphy and chronostratigraphy in the British Isles. Journal of the Geological Society of London, vol. 150, pp.427-446. | |||
| Symes, R.G. & Wilkinson, S.B., 1886. Explanatory memoir to accompany sheet 44. Memoirs of the Geological Survey of Ireland, pp.1-44. | |||
| Map(s): | See 1:50,000 O.S. Sheet 17 (Lower Lough Erne). | ||
| Record type: | ESCR report | ||
| Entered by: | Doughty, P.J. | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Lurgan River, Mullylusty Townland, County Fermanagh, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=198. Accessed on 2026-11-06. |
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