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Earth Science Conservation Review
| Bellanaleck Quarry | Fermanagh |
| Site number: | 177 | File Number: | H23 |
| ESCC: | ED | ||
| Locality Type: | Quarry (disused) | Status: | ASSI |
| Grid Reference: | H234389 Centroid | ||
| Google maps: | 54.29882,-7.64057 | ||
| County: | Fermanagh | Council area: | Fermanagh & Omagh District Council |
| Period: | Carboniferous | ||
| Stages: | Courcyean, Tournasian | ||
| Lithostrat: | Tyrone Group | ||
| Site Description | |
|---|---|
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| Highlights: | |
The Carboniferous rocks exposed in Bellanaleck Quarry are a previously unrecognised occurrence of Waulsortian mound limestones and are only the second occurrence of these rocks in Northern Ireland. They contain a diverse macrofauna that includes, for the first time in Northern Ireland, a suite of trilobites that are of late Tournaisian (Courceyan) age. These are the oldest rocks of the Tyrone Group exposed in Subarea-1. Together with the Belleek Waulsortian, these are the most northerly occurrence of this lithology and facies in Ireland, in Great Britain and in western Europe. | |
| Introduction: | |
In the outcrop of the Ballyshannon Limestone Formation south of Enniskillen there are very few exposures and the upper and lower limits of the formation and its age are very poorly constrained. Given the paucity of outcrops in this large area, which lies within the southwest Fermanagh drumlin field and adjacent to the meandering River Erne, between the lower and upper loughs, it is somewhat surprising to encounter a substantial quarry excavated into a rock cored drumlin, about 250m northeast of Bellanaleck. Location: Bellanaleck Quarry is located about 250m NE of the eponymous village on the western edge of the alluvial floodplain of the River Erne. The only other exposures of the same limestone located within this area occur as low rock knolls at H241 385, some 600m SE of Bellanaleck, on the north side of the road to Mill Lough. Bibliographic Review: The 6-inch fieldmaps of the Geological Survey of Ireland (Fermanagh 27SW, 1878-80) confirm the existence of Bellanaleck Quarry, and the knoll outcrops to the southeast, at that time. They also depict limestone at surface, beneath the village, east of the crossroads, and in a large quarry, now infilled, which was located about 100m south of the crossroads. Intriguingly Wilkinson also marked an extensive outcrop of "compact grey limestone" at Mullymesker, 1500m west of the crossroads. He could not define a dip or strike at any of the limestone outcrops and considered the rocks to be almost horizontal. The limestones were assigned by him to the Lower Limestone division of the Carboniferous System and as such this represents the most accurate assessment of their age despite the more recent work of the Geological Survey of Northern Ireland. Large collections of macrofauna, in particular brachiopods, were made by the GSNI, in the 1970's, from this quarry but they contained no diagnostic taxa and the age assigned to the limestones ranged from the Lower Limestone (Ballyshannon Formation) to the Upper Limestone (Glencar-Dartry Formations). In the end the rocks in this area were assigned, somewhat curiously, a d2b age (equivalent to the Calp Sandstone or the late Arundian Mullaghmore Sandstone Formation) on the 1:250,000 Geological Map of Northern Ireland (1972) and a d2c age (equivalent to the Asbian Upper Limestone) on the 1:50,000 geological map of the Enniskillen area (Sheet 45, 1982). The true age of the limestones in Bellanaleck Quarry and their association with the Waulsortian facies has thus only been recognised recently. General Geology: In the area of southwest Fermanagh, and in particular the very badly exposed ground south of Enniskillen and around Bellanaleck, the precise stratigraphical position of the limestones in the quarry are unclear. The regional dip of the Carboniferous is to the southwest from the basal red-beds of the Ballyness Formation and the peritidal carbonates and shales of the Clogher Valley Formation that are exposed at Enniskillen and on the north side of the Clogher Valley, to the late Dinantian and early Silesian sequences of Cuilcagh Mountain and Slieve Rushen in the extreme southwest of the county. The nature of the strata underlying and succeeding the limestones at Bellanaleck Quarry is not known. Waulsortian: The term Waulsortian was introduced more than a century ago for a particular association of mid-Dinantian limestones in Belgium. Soon after its introduction the term achieved the same stratigraphic status as Tournaisian and Vis‚an but was very quickly shown to represent, in reality, a late Tournaisian to early Vis‚an 'reef' facies with distinctive lithological and faunal characters. Since then the Waulsortian has been recognised throughout Europe, and in Britain and Ireland, and since the 1950's in North America and possibly Arctic Canada. The term Waulsortian is not synonymous for mudmounds and therefore the mudmounds of the Dartry Limestone Formation do not form part of the Waulsortian. Recent research suggests that the Waulsortian buildings of Belgium formed on the distal part of a ramp. Growth seems to have started in the aphotic zone but, because of upward growth and probable sea-level changes, it ended in much shallower waters. Judging from the differences in thickness between the Waulsortian facies (buildups) and their proximal (bedded) lateral equivalents, the buildings had a depositional relief of as much as 200m between the shallow waters of the upper parts of the building and the deep basins only a few hundred metres away (Lees, 1988). Waulsortian limestones first formed on the outer edge of a shelf in the south of Ireland during late Tournaisian times and spread northwards to eventually cover an area of approximately 20,000 square kilometres. During the Chadian Stage Waulsortian growth ceased, first in the north and later in the south. By early Arundian times the Waulsortian was extinct. The approximate northern limit of the Waulsortian is a line joining Galway to the southwestern tip of the Down-Longford inlier and then following the southern margin of the inlier to the east coast of Ireland just north of Drogheda (Sevastopulo, 1982). | |
| Description: | |
Bellanaleck Quarry is located on the southeast side of a N-S orientated, rock-cored drumlinoid ridge. It comprises a vertical rock face, with a maximum height of 10-12m, on the west side beneath a collection of farm buildings and is open to the east. The limestone is generally unbedded although at the north end of the face there is a suggestion of widely spaced 'bedding' surfaces inclined northwards at c.30 deg. The dominant lithology is a pale to medium grey fine-grained limestone which is riddled with laminated veins (crusts) of dark to white sparry calcite that are intimately associated with large unbroken fronds of fenestellid bryozoa. This lithology is virtually identical to Assemblage A of the 4 main assemblages (A-D) of sedimentological and faunal components that make up the Waulsortian. Assemblage A is thought to represent the deepest environment in the buildup and is associated with fenestellid bryozoa, crinoid debris and an abundant and diverse fauna of brachiopods, many of which occur in a probable life position and with superbly preserved conjoined valves. The following brachiopods occur in these limestones at Bellanaleck: Acanthoplecta mesoloba, Alitaria panderi, Antiquatonia cf. hindi, A. insculpta, Avonia cf. davidsoni, Dielasma sp., Eomarginifera sp., Georgethyris lobata, Krotovia sp., Leptagonia analoga, Orthotetoids, Pleuropugnoides pleurodon, Plicochonetes sp., Productina margaritacea, Productus productus, Pugnax cordiformis, Pugnax pugnus, Spirifer bisulcatus, S. striatus, Syringothyris sp. Unfortunately this brachiopod assemblage is not diagnostic of age but is strongly facies controlled and many of the forms listed above occur in much younger (late Vis‚an) limestones, for example in the Dartry Limestone Formation in Fermanagh and in the Blackstokes Limestone Formation at Benburb. Corals are universally extremely rare in the Waulsortian except for Amplexus and at Bellanaleck this is represented by the species A. coralloides. To date only one poorly preserved goniatite has been collected from this quarry and is assigned to the genus Dzhaprakoceras, which has a late Tournaisian (Courceyan) to Arundian age range. The microbiota of the typical Waulsortian is distinctive. The bank limestones contain numerous calcisphaeres and a restricted assemblage of foraminifera amongst which Eotextularia diversa, Tetrataxis and various endothyrids are most common along with various microfossils of uncertain affinities. A sample of limestone from Bellanaleck Quarry contains the following microbiota: calcisphaeres, Earlandia sp., Endothyra spp., Eotextularia diversa, lituotubellid, Priscella sp.,Tetrataxis sp., Kamaenella sp., Salebra sp. The presence of E. diversa constrains the age as no younger than the Arundian and Tetrataxis does not occur below the base of the upper Tournaisian, thus giving a maximum age. One of the Endothyra in this limestone compares very closely with a specimen illustrated from the early Chadian Clitheroe Limestone Formation of the Craven Basin in the north of England (Riley, 1990). A collection of small trilobites from the north end of the quarry consists of the following taxa: Bollandia cf. rugiceps, Brachymetopus maccoyi, Cummingella sp. nov., Namuropyge sp., Winterbergia sp. nov. aff. W. hahnorum. B. maccoyi is the most numerous and dominant species of trilobite in the collection and has a late Tournaisian (Courceyan) to Arundian age range. The most revealing components are Bollandia cf. rugiceps which is known from the uppermost early Chadian and late Chadian, and Cummingella sp. nov. (this is the species named as Cummingella parkinsoni (Riley, 1982 nomen nudum)), which has only been recorded from the uppermost early Chadian of the Craven Basin, in the Bellman Limestone Member of the Clitheroe Limestone Formation (Riley, 1992, 1990). | |
| Interpretation: | |
The occurrence of limestones of the Waulsortian facies at Bellanaleck may indicate an unbroken history of deposition from the late Tournaisian basal clastic red-beds through to the mid-Dinantian marine sequence that includes the Ballyshannon Limestone and succeeding shale and limestone formations of the Tyrone Group. The demonstration of strata of an early Chadian (late Tournaisian) age is a rare event in Northern Ireland and can only be repeated for strata that occur on the north side of the Clogher Valley. Elsewhere in the Province there is good evidence of marine regression in early Chadian times and exposure of older Carboniferous sedimentary rocks. Because of the poor exposure in the Enniskillen-Bellanaleck area we have no information on the distribution of facies in this part of the Northwest Basin during the Chadian and no knowledge of the extent of this Waulsortian buildup. | |
| Conclusions: | |
Despite the isolated nature of the limestone exposure at Bellanaleck this quarry is one of the most important geological ASSI in the Carboniferous outcrop of Northern Ireland. a) This is one of only 2 localities where Waulsortian limestones occur in Northern Ireland. b) This Waulsortian buildup is located some 60km north of the limit formerly imposed on the development of this facies in Ireland. c) This is the only locality in Northern Ireland where an early Chadian age is proven and is the only locality where the diagnostic trilobite assemblage is found. d) Bellanaleck Quarry is one of two Waulsortian localities in Northern Ireland. These are the most northerly occurrences of the Waulsortian in Ireland, Great Britain and Western Europe. | |
| Notes: | |
For information on other sites in Subarea-1 see; Key Site 1174 - Subarea-1; Derrygonnelly-Marble Arch-Cuilcagh. | |
| Keywords | |
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| Minerals: | Sparrite |
| Rocks: | Limestone |
| Fossil Groups: | Brachiopod, Coral, Foraminifera, Goniatite, Microfossil, Microfossils, Polyzoan, Trilobite |
| Fossil List: | Bollandia cf. rugiceps, Brachymetopus maccoyi , Eotextularia diversa |
| Relations: | Marine sediments |
| Access | |
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| Approach: | 5km S of Enniskillen. |
| References (10) | |||
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| 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. | |||
| Brunton, C.H.C. & Mason, T.R., 1979. Palaeoenvironments and correlations of the Carboniferous rocks in west Fermanagh, Ireland. Bulletin of the British Museum (Natural History), Geology, vol. 32, pp.91-108. | |||
| Lees, A., 1988. Waulsortian 'reefs': the history of a concept. Memoires de l'Institute Geologique de l'Universite de Louvain, vol. 34, pp.43-55. | |||
| 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. | |||
| Philcox, M.E., Baily, H., Clayton, G. & Sevastopulo, G.D., 1992. Evolution of the Carboniferous Lough Allen Basin, Northwest Ireland. Special Publications of the Geological Society of London, numb. 62 In Basins on the Atlantic Seaboard: Petroleum Geology, Sedimentology and Basin Evolution., pp.203-215. | |||
| Riley, N.J., 1982. Early Visean trilobite and ammonoid faunas in the western part of the Craven Basin (Ph.D. thesis). (Thesis) University of Bristol. | |||
| Riley, N.J., 1982. Stratigraphy of the Warston Shale Group (Dinantian), Craven Basin, north-west England. Proceedings of the Yorkshire Geological Society, vol. 48 pt. 2, pp.163-187. | |||
| Sevastopulo, G.D., 1982. The age and depositional setting of Waulsortian Limestone in Ireland. In Symposium on the Environmental Setting and Distribution of the Waulsortian Facies., pp.65-79 El Paso Geological Society and University of Texas at El Paso. | |||
| West, I.M., Brandon, A. & Smith, M., 1968. A tidal flat evaporitic facies in the Visean of Ireland. Journal of Sedimentary Petrology, vol. 38, pp.1079-1093. | |||
| Record type: | ESCR report | ||
| Entered by: | Doughty, P.J. | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Bellanaleck Quarry, County Fermanagh, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=177. Accessed on 2026-11-05. |
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