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Earth Science Conservation Review
| Creevagh Hill Old Quarry | Londonderry |
| Site number: | 154 | ||
| ESCC: | ED | ||
| Locality Type: | Quarry (disused) | Status: | ASSI |
| Grid Reference: | C401158 Centroid | ||
| Google maps: | 54.98853,-7.37355 | ||
| County: | Londonderry | Council area: | Derry City & Strabane District Council |
| Period: | Precambrian | ||
| Stages: | Dalradian | ||
| Lithostrat: | Londonderry Formation | ||
| Site Description | |
|---|---|
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| Highlights: | |
The disused quarry pit at Creevagh contains good quality outcrop of the Londonderry Formation. Interbedded schistose grits and phyllites with clearly displayed beddingcleavage relationships and sedimentary structures showing "way up" of the strata. | |
| Introduction: | |
This site is located about 3km WSW of the City of Londonderry and is enclosed within fenced pastureland on a NE to SW trending ridge where drift cover is thin and there is intermittent rock exposure. Access to the site is via the B193, heading south-west from Londonderry, then along the Braehead Road, Creevagh Road and finally the Heather Road. On the first edition of the one inch to one mile geological map of the area (Londonderry, Sheet 11) (Geological Survey of Ireland, 1890, Wilkinson, 1908) all of the strata in the vicinity of Creevagh Hill were included within the general category "mica schists". The rocks at and around Creevagh Hill form part of the thick succession of Upper Dalradian metagreywackes at the core of a broad syncline centred on Lough Foyle (Lough Foyle Syncline). These rocks were formerly referred to as the Lough Foyle Succession and were correlated with the Loch Awe Succession in Scotland. (Pitcher, 1972) The first formal stratigraphic subdivision of the Lough Foyle Succession came as a result of mapping in Co. Londonderry by the Geological Survey of Northern Ireland (1981, 1995, 1997) and as a result, the rocks at Creevagh Hill are now included within the Londonderry Formation, the youngest subdivision of the Southern Highland Group in the Lough Foyle Syncline in north Londonderry, see table below. TABLE TO BE ADDED Dalradian stratigraphy and ESCR sites in the northern Sperrin Mountains. | |
| Description: | |
The site is a disused quarry pit consisting of a single face between 3m and 4m high and about 40m long. Despite a period of dereliction and some dumping of farm waste, the exposure is clean and of high quality. The succession consists of orangey-brown, coarse and gritty psammite (metagreywacke) interbedded in equal proportions of grey, greenish grey and silvery phyllite and quartz mica schist.  Bedding surfaces (S0) can be clearly seen at a number of points with dips consistently towards the N and NW (120°24°N). Some of the more massive psammite units have gritty bases and contain grey and blue subrounded quartz, subangular white feldspar and occasionally, black pelite clasts up to 2mm diameter. Grading and bedform geometry in these gritty units indicate that the succession is right way up and is younging towards the north-west. All rocks at this site are affected by a close-spaced, penetrative cleavage (092°40°N) which everywhere appears to be subparallel to, but more steeply inclined than, bedding. This cleavage is the regionally dominant fabric referred to as S1 by Bazley et al. (1997) and is related to the major fold structure in the area (Lough Foyle Syncline). However, since these folds are now interpreted as F2 structures (Arthurs et al., 1994) it seems more likely that, despite no earlier cleavage being visible at outcrop, the dominant cleavage seen at Creevagh Hill equates with the regional S2 as seen further to the south. A number of late-stage (post-D2) kink-folds cut across S2. The axial trace of these brittle structures trend 050° 70°SE with vergence towards the south-east. | |
| Importance: | |
Creevagh Hill Quarry contains some of the best exposures of the Londonderry Formation remaining in the area west of the City of Londonderry. The site offers an opportunity to study sedimentological aspects of the Londonderry Formation along with structural relationships on the south-eastern limb of the Lough Foyle Syncline. There is likely to be ongoing interest in this site because of its location in a key area of interest, mid-way between the Dalradian successions of Donegal and the Sperrin Mountains. | |
| Interpretation: | |
During the Upper Dalradian, the rocks of the Londonderry Formation were deposited as turbidites in An open marine environment within a trough or basin which subsided gradually to accommodate the accumulating sediments (Bazley, 1997). During the Caledonian Orogeny, Dalradian rocks throughout the British Isles, underwent major regional scale deformation accompanied by metamorphism. As a result of folding and SE-directed thrusting, rocks at this site now lie on the southern limb of the Lough Foyle Syncline, a complementary structure to the Sperrins Overfold. These two major structures have been interpreted as south-westerly continuations of the Loch Awe Syncline and the Tay Nappe respectively (Pitcher et al., 1972, Bazley et al., 1997). The metamorphism that accompanied the deformation was comparatively low-grade. The common occurrence of quartz- chlorite-epidote mineral assemblages is consistent with metamorphism under quartz-albite-muscovite-chlorite sub-facies conditions in the Greenschist Facies. | |
| Conclusions: | |
A strong case can be made for conserving Creevagh Hill Quarry as a site of national importance. It is in an area where outcrop is otherwise poor and diminishing as existing pits are filled or built over. The site offers an opportunity to study the sedimentology and structure of rocks of the Londonderry Formation in the important transitional area between the Sperrin Mountains and Donegal. | |
| Notes: | |
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 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 162 - Loughareema Channel Key Site 163 - Knocknacarry Bridge Key Site 164 - Cushendun Bay and Rock Port 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 | |
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| Rocks: | Greywacke, Metagreywacke, Phyllite, Psammite, Schist |
| Structures: | syncline |
| Measurements | |||||
|---|---|---|---|---|---|
| Length: | ~40m | Width: | Height: | 3-4m | |
| Depth: | Area: | ||||
| Access | |
|---|---|
| Approach: | Access to the site is via the B193, heading south-west from Londonderry, then along the Braehead Road, Creevagh Road and finally the Heather Road. |
| Management: | |
The site is located within fenced pastureland and is accessible over a locked gate leading directly from Heather Road. None of the quarry faces exceeds 5m height and currently all appear to be stable enough to allow safe access. There is no need to put hammering or sampling restrictions on the site which can withstand all reasonable sampling pressure Currently some farm machinery and silage bales are stored in the pit and there has been some infilling with organic waste. | |
| Threats: | The main threat to this site is likely to be from further infill and possibly from any future reprofiling and improvement of the surrounding land. |
| References (3) | |||
|---|---|---|---|
| Bazley, R.A.B., Brandon, A. & Arthurs, J.W., 1997. Geology of the Country around Limavady and Londonderry GSNI Technical Report 97/1. | |||
| Pitcher, W.S. & Berger, A.R., 1972. The Geology of Donegal: A study of granite emplacement and unroofing Wiley - Interscience, New York & London. | |||
| Wilkinson, S.B., McHenry, A., Kilroe, J.R. & Seymour, H.J., 1908. The geology of the country around Londonderry Memoirs of the Geological Survey of Ireland, HMSO, Dublin. | |||
| Map(s): | GSI (1890). 1:63,360 Geological Sheet 11 (Londonderry), Dublin, OS for GSI GSNI (1981). 1:50,000 Limavady, Northern Ireland Sheet 12 and part of Sheet 6, Solid, Southampton, OS for GSNI GSNI (1995). 1:50,000 Londonderry, Northern Ireland Sheet 11, Solid and Drift, BGS, Keyworth, Nottingham 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. Creevagh Hill Old Quarry, County Londonderry, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=154. Accessed on 2026-11-06. |
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