| Previous Site | Next Site |
Earth Science Conservation Review
| Loughareema - Dalradian | Antrim |
| Site number: | 162 | ||
| ESCC: | EO | ||
| Locality Type: | Crag, Crags | Status: | ASSI |
| Grid Reference: | D206356 Centroid | ||
| Google maps: | 55.15331,-6.10815 | ||
| County: | Antrim | Council area: | Causeway Coast & Glens Borough Council |
| Period: | Precambrian | ||
| Stages: | Dalradian | ||
| Lithostrat: | Leckpatrick Green Beds, Runabay Head Formation, Southern Highlands Group | ||
| Site Description | |
|---|---|
 | |
| Highlights: | |
The site consists of series of exposures along the steep sides of the Loughareema glacial overflow channel. The rocks at this site include quartz-albite schist, psammite and biotite and hornblende "green beds" (Leckpatrick Green Beds Member). These strata constitute the uppermost stratigraphic levels of the Runabay Formation of the Southern Highland Group (Upper Dalradian). | |
| Introduction: | |
Loughareema is located at the northern end of the glacial spillway through which the main (A2) Cushendall to Ballycastle Road passes about 5km north-west of Cushendun. The site is accessible from a rough parking area 500m south of Loughareema (Vanishing Lake). On the first edition of the one inch to one mile geological map of the area (Ballycastle, Sheet 8 (Geological Survey of Ireland, 1887), the rocks at Loughareema were classified simply as "gneiss, mica & hornblende schist" and referred to jointly as "crystalline schists". Both McCallien (1931) who produced the first detailed lithostratigraphic map of the Dalradian of North-east Antrim and Bailey & McCallien (1934) adopted the lithostratigraphic nomenclature that was currently in use in Scotland. McCallien's stratigraphy for Co Antrim was predicated on a structural interpretation which viewed north-east Antrim as a south-westerly continuation into Ireland of the recumbent fold structures already identified on the Cowal Peninsula, SW Scotland (Gunn et al., 1897). According to Bailey et al., (1934), the Dalradian strata in the vicinity of Loughareema form part of the Pitlochry Schists (Upper Dalradian) and lie at the core of a tight, downwards-facing structure (is equivalent to the Carrick Castle Fold, Argyll). The second edition of Sheet 8 (Ballycastle) (Geological Survey of Northern Ireland, 1963; Wilson et al., 1966) contained a revised lithostratigraphy together with an alternative to Bailey and McCallien's interpretation of the regional structure. A more formal approach to lithostratigraphic terminology for the Dalradian of north-east Antrim was adopted for the first edition of the Solid Geology Map of Northern Ireland (Geological Survey of Northern Ireland, 1977). For the first time, local lithostratigraphic names were applied and the rocks around Loughareema were classified as part of the Altmore Schists. Arthurs (1976) produced a major reinterpretation of the stratigraphy and structure of North-east Antrim in which the rocks at Loughareema were included within the Runabay Head Formation, see table below. The Runabay Head Formation as defined by Arthurs includes the Leckpatrick Green Bed Member at the stratigraphic base and the Carnaneigh Green Bed Member at the top. This revised stratigraphy has been incorporated in the second edition of the solid geology map (Geological Survey of Northern Ireland, 1997). TABLE TO BE ADDED Dalradian stratigraphy and ESCR sites in North-east Co. Antrim. | |
| Description: | |
Various lithologies belonging to the Runabay Head Formation are exposures in the steep rocky sides of the Loughareema meltwater channel extending southwards from Loughareema. Much of the western side of the channel consists of dark green hornblende schists (Leckpatrick Green Bed Members) which are massive in parts and resemble tectonised metabasites. At a former roadside quarry pit [D207 357] now used as a parking area,
 This lithological variation can be traced further northwards along the partially overgrown crags on the western side of the channel to the point where it crosses the road. Here, quartzo-feldspathic schists with psammites (containing muscovite and porphyroblastic oligoclase) are faulted against hornblende and biotite green beds (Wilson et al., 1966). These green beds are also exposed along the southern shore of Loughareema. A short distance to the north of this outcrop, chalk debris marks the proximity of a major unconformity between the Dalradian and a small outlier of chalk of the Ulster White Limestone Formation (Cretaceous). Throughout this extensive site there is a highly variable development of porphyroblastic albite with millimetre scale, pale pink and pinkish white idiomorphic albite crystals formed particularly in the most biotite-rich schist horizons. Albite is particularly well developed on the roadside crag on the eastern side of the road where the glacial channel crosses, close to the western shore of Loughareema. Here, quartz-mica schists are interbedded with thin partings of dark green to black biotite schist containing patchy developments of pinkish white porphyroblastic albite. These albites are particularly conspicuous on, and sit proud of, weathered surfaces. At this locality, it is evident that the development of albite, although closely related to the composition of the host, is completely dependent upon the rock composition. Tourmaline occurs as a common accessory mineral in these rocks in the form of single needles and as aggregates of acicular crystals on foliation surfaces, particularly in the pale green chloritic schist horizons. Reynolds (1942) noted the presence of tourmaline in the roadside quarry [D207 357]. | |
| Importance: | |
This site has considerable stratigraphic importance since it provides access, in an otherwise poorly exposed area, to outcrops of the Leckpatrick Green Bed Member and the uppermost stratigraphic levels of the Runabay Head Formation as defined by Arthurs (1976). Green beds acts as important marker horizons within the Upper Dalradian succession which is otherwise rather monotonous and dominated by siliciclastic lithologies. The Leckpatrick Green Beds in particular played an important role in the development of ideas about the stratigraphy and regional structure of north-east Antrim. Locations within this site have been cited in a number of petrological studies and are particularly instructive for demonstrating the development of albite schists and the nature of the green beds (Wilson et al., 1966; Reynolds, 1942). | |
| Interpretation: | |
The strata at Loughareema are a mixture of contrasting siliciclastic and volcanogenic sediments typical of the Southern Highland Group throughout northern Britain. During late Proterozoic (Upper Dalradian) times, a number of marine sedimentary basins formed along the unstable margin of the Laurentian continent. These basins were infilled and subsided under the weight of the accumulating siliciclastic turbidite facies sediments derived from the nearby continental landmass to the north-west. The presence of green beds is a common feature of the stratigraphy of the Upper Dalradian throughout Northern Britain. Towards the end of Middle Dalradian times (Tayvallich Subgroup, Argyll Group), the break up and extension of the Laurentian continental margin was accompanied by a major upsurge of volcanic activity. This activity involved the eruption of mainly basaltic lavas and tuffs and persisted well into Upper Dalradian times. The green beds are believed to have formed as a result of erosion of these volcanic rocks. Knill, (in Wilson et al., 1966) noted colour and lithological banding in green beds (Leckpatrick Green Bed Member) at Loughareema and cited this as evidence to support the sedimentary origin of these rocks. The Caledonian Orogeny resulted in deformation and the thermo-dynamic metamorphism of the Upper Dalradian rocks. In north-east Antrim, as in Scotland and the Sperrin Mountains this was a complex polyphase deformation which resulted in folding and the formation of up to four recognisable cleavages (Arthurs, 1976; Goldring, 1961). Structurally, this site now lies on the downwards facing inverted limb of the Altmore Anticline a structure interpreted as the south-westerly continuation of the Cowal Anticline in SW Scotland (Arthurs, 1976). The rocks at Loughareema contain mineral assemblages which indicate that the regional metamorphism took place under conditions of pressure and temperature within the quartz-albite-muscovite-chlorite sub-facies of the Greenschist Facies. | |
| Conclusions: | |
Loughareema is a site of national importance. It has strong local significance as a stratigraphic site containing outcrops of the topmost beds of the Runabay Head Formation and the Leckpatrick Green Bed Member. Some of the localities have been cited in the scientific literature and were used to demonstrate textures within the albite schists and sedimentary variation within the green beds. | |
| Notes: | |
For site specific information and references on other Dalradian sites in North-east Antrim see the following sites: Key Site 155 - Benvan Key Site 156 - Escort Port Key Site 157 - Torr Head Key Site 158 - Altmore Burn Key Site 159 - Leckpatrick Point Key Site 160 - Carnaneigh Key Site 161 - Loughan Bay Key Site 163 - Knocknacarry Bridge Key Site 164 - Cushendun Bay and Rock Port For site specific information and references on other Dalradian sites in the Sperrin Mountains, Londonderry and Tyrone see the following sites: For Central and Southern Sperrin Mountains: Key Site 130 - Butterlope Glen Key Site 131 - Craig Key Site 132 - Mullaghcarbatagh Key Site 133 - Henry's Bridge, Glensass Burn Key Site 134 - Oughtboy Burn Key Site 135 - Garvagh Burn Key Site 136 - Barnes Gap Key Site 137 - Barnes Burn Key Site 138 - Golan Burn Key Site 139 - Glendarragh Burn, Glenlark Key Site 140 - Mountfield Old Quarry Key Site 141 - McNally's Burn, Broughderg For North Sperrin Mountains and Londonderry: Key Site 142 - Letterbrat Quarry Key Site 143 - Banagher Glen Quarry Key Site 144 - Strabane Quarry Key Site 145 - Glenmornan River, Artigarvan Key Site 146 - Balix Hill Key Site 147 - Drain Quarry Key Site 148 - Kildoag Quarry Key Site 149 - Loughermore Mountain Key Site 150 - Burntollet and Tamnymore Wood Key Site 151 - Dog Leap, Limavady Key Site 152 - Kittybane Quarry Key Site 153 - Prehen Quarry Key Site 154 - Creevagh Hill Old Quarry For general information on the Dalradian rocks of Northern Ireland see the following site: Key Site 124 - The Dalradian Rocks of Northern Ireland For general and site specific information on the Pre-Dalradian rocks of Northern Ireland see the following site: Key Site 123 - The Pre-Dalradian Rocks of Northern Ireland For general information and an extensive reference list on the Precambrian of Northern Ireland see the following site: Key Site 122 - An Introduction to the Precambrian of Northern Ireland | |
| Keywords | |
|---|---|
| Minerals: | Albite |
| Rocks: | Green beds, Schist |
| Access | |
|---|---|
| Management: | |
The majority of outcrops at Loughareema lie in rough pastureland fenced off from the main Cushendall to Ballycastle Road. From the point of view of safety, extreme care should be exercised when accessing certain parts of the site, especially at the northern end where outcrops, containing some of the best examples of albite schists and green beds, are unfenced and very close to the roadside on a blind bend. Although this is a geographically extensive site with plenty of outcrops providing alternative exposures of some lithologies, some geological features such as good examples of albite schists are less common. For this reason it may be worth considering imposing hammering restrictions. | |
| Threats: | At present there are no obvious threats to the integrity of the site. |
| References (6) | |||
|---|---|---|---|
| Arthurs, J.W., 1976a. The geology and metalliferous mineral potential of the Sperrin Mountains area Geological Survey of Northern Ireland Special Report. | |||
| Bailey, E.B. & McCallien, W.J., 1934. The metamorphic rocks of North-east Antrim Transactions of the Royal Society of Edinburgh: Earth Sciences, vol. 58, pp.163-177. | |||
| Gunn, W., Clough, C.T. & Hill, J.B., 1897. The Geology of Cowal Memoir of the Geological Survey of Scotland. | |||
| McCallien, W.J., 1931. A contribution to the correlation of the Dalradian rocks of Scotland Geological Magazine, vol. 68, pp.153-175. | |||
| Reynolds, D.L., 1942. The albite schists of Antrim and their relationship to Caledonian orogenesis Proceedings of the Royal Irish Academy, vol. 48 pt. B, pp.43-66. | |||
| Wilson, H.E. & Robbie, J.A., 1966. Geology of the country around Ballycastle. Memoirs of the Geological Survey Northern Ireland. | |||
| Map(s): | GSI (1887). 1:63,360 Geological Sheet 8 (Ballycastle), Dublin, OS for GSI GSNI (1963). 1:63,360 Ballycastle, Northern Ireland Sheet 8, Drift, Southampton, OS for GSNI GSNI (1977). 1:250,000 Northern Ireland, Solid Geology (1st edition), Southampton, OS for IGS GSNI (1997). 1:250,000 Northern Ireland, Solid Geology (2nd edition), BGS, Keyworth, Nottingham | ||
| Record type: | ESCR report | ||
| Entered by: | E M Porter | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Loughareema - Dalradian, County Antrim, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=162. Accessed on 2026-11-06. |
| Previous Site | Next Site |