| Previous Site | Next Site |
Earth Science Conservation Review
| Tullanaguiggy | Fermanagh |
| Site number: | 249 | File Number: | H26 |
| ESCC: | EO | ||
| Locality Type: | Stream section | Status: | ASSI |
| Grid Reference: | H218616 Centroid | ||
| Google maps: | 54.50281,-7.66348 | ||
| County: | Fermanagh | Council area: | Fermanagh & Omagh District Council |
| Period: | Carboniferous | ||
| Stages: | Westphalian | ||
| Lithostrat: | Slievebane Group, Tullanaglare Mudstone Formation | ||
| Site Description | |
|---|---|
| Highlights: | |
The stratotype section of the Tullanaglare Mudstone Formation is the best exposure of this unit in the Milltown Segment. Miospore assemblages contain taxa diagnostic of the RA and NJ Zones (Langsettian and Duckmantian stages) of the Westphalian. | |
| Description: | |
The stratotype section of the Tullanaglare Mudstone Formation is located in the north-flowing stream that marks the boundary between the eastern edge of Tullanaguiggy Townland and the western margin of the narrow southerly projection from Kiltierney Townland, 4km NNW of Irvinestown. Exposure occurs over about 100m of stream bed and near its northern margin extends eastwards for about 150m forming a low ridge, with a steep north face, on which bedrock is concealed only by thin till. About 50m of strata are exposed in the section, and are inclined northwards at about 75-80 deg. Because of the pedogenic origin of many of the sediments bedding is often indistinct. The base of the formation, at the north end of the section is concealed by glacial till. The formation consists of grey and green-grey sediments (Photographs 81 and 82), often mottled in shades of purple and red, comprising calcareous mudstones, laminated mudstones, siltstones, quartz-clastic palaeosols and sandy palaeosols with calcrete nodules. Out of a total of 13 samples submitted for palynological analysis only two produced significant numbers of miospores. A sample of pale pink-stained, green palaeosol that occurs about 5m north of the most southerly exposure contained the following miospores: Calamospora parva Crassispora kosankei Densosporites anulatus Dictyotriletes bireticulatus Florinites mediapudens Laevigatosporites demoinesensis Lycospora granulata L. pusilla Raistrickia fulva Schulzospora rara The significant taxon in this assemblage is Schulzospora rara which has a very restricted range (in a chronostratigraphical sense) and is the index species of a miospore subzone that occurs at the very top of the Langsettian Stage (Westphalian A). Its presence here with D. bireticulatus, L. desmoinesensis and R. fulva is compatible with that age. The strata between the above locality and the second productive sample, which consists of laminated green mudstones, 0.9m to the north, and which are exposed in the west bank of the shallow plunge pool in the wider part of the stream course, are faulted. This miospore assemblage includes the following forms: Calamospora microrugosa C. pallida C. parva Crassispora kosankei Cyclogranisporites aureus Densosporites anulatus D. sphaerotriangularis Endosporites globiformis Florinites sp. Microreticulatisporites nobilis Savitrisporites nux Vestispora costata V. cf. pseudoreticulata This association of miospores indicates a Westphalian B age; in British coalfields E. globiformis and M. nobilis first appear in the Clay Cross Marine Band at the base of the Duckmantian (Westphalian B) Stage that is equivalent to the base of the NJ Miospore Zone. The top of the formation, at the south end of the section, and the base of the succeeding Drumlish Conglomerate Formation, is concealed in the stratotype. This part of the succession in the Slievebane Group is however exposed at 3 localities in the central part of the outcrop of the Tullanaglare Formation, north of Raw Lough. At the top of the formation is the Drumgivery Limestone Member which consists of 0.3-0.5m of unfossiliferous, massive, pink pedogenic limestone (Photograph 83) composed of at least 90% micrite with minor amounts of fine detrital quartz and clay materials. The top of this limestone is overlain directly by conglomerates representing the base of the Drumlish Formation. | |
| Interpretation: | |
Although Coal Measure strata no younger than the Westphalian A are known from several areas in Ireland (Sevastopulo, 1981), including Coalisland in Co. Tyrone (Fowler & Robbie, 1961), the strata of the Tullanaglare Mudstone Formation represent the youngest dated Westphalian rocks that are exposed on-shore in Ireland. These sediments are slightly younger than the rocks in the Coalisland Coalfield. They accumulated mainly as palaeosols under partially waterlogged conditions on a topographically more elevated sector of an extensive alluvial plain on which coal- forming swamps and lakes were developing, to the east at Coalisland and southwards throughout Ireland. Purple-red mottling in otherwise grey and green sediments, as in the Tullanaglare Formation, is interpreted as evidence of improved drainage of the soil profile, in areas of low depositional rates. In contrast, sediments between coal seams at Coalisland are exclusively grey and green mudstone and sandstones, with no incipient reddening, that probably accumulated in poorly drained alluvial swamps with no significant fluctuations in the water table. Laterally continuous and thick developments of calcrete profiles provide valuable insights into the maturity of the pedogenic process and is a reflection of an increase in residence time of a particular horizon in the zone of pedogenesis. In areas of fine- textured substrates it is also believed to reflect the increasing channelization of the sediment transport system down the alluvial fans. Thus many parts of the fan surface were starved of sediment and soil formation would result in more mature soil profiles. The development of thick calcrete profiles, such as the Drumgivery Limestone Member, supports this conclusion and is indicative of a long episode of climatic aridity. Such an event may be linked to the growth of a rain shadow associated with uplift of mountains, whose erosion ultimately led to the accumulation of conglomerates of the Drumlish Formation. | |
| Conclusions: | |
The Tullanaglare Mudstone Formation includes a group of fine- grained sediments that are the youngest, accurately dated, Carboniferous rocks exposed in Ireland. Miospore assemblages recovered from the stratotype section indicate a Westphalian A and B age. | |
| Notes: | |
For information on other sites in Subarea-4 see; Key Site 1177 - Subarea-4; Fintona Block. | |
| Keywords | |
|---|---|
| Rocks: | Calcrete, Mudstone |
| Fossil Groups: | Miospore |
| Fossil List: | Lycospora pusilla, Schulzospora rara |
| Access | |
|---|---|
| Approach: | The eastern edge of Tullanaguiggy Townland and the western margin of the narrow southerly projection from Kiltierney Townland, 4km NNW of Irvinestown. |
| Map(s): | See 1:50,000 O.S. Sheet 18 (Enniskillen). | ||
| Record type: | ESCR report | ||
| Entered by: | Doughty, P.J. | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Tullanaguiggy, County Fermanagh, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=249. Accessed on 2026-11-07. |
| Previous Site | Next Site |