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Earth Science Conservation Review
| Magheramorne Quarry, Larne – Clay-with-Flints |
| Site number: | 1309 | ||
| Locality Type: | Status: | ESCR | |
| Grid Reference: | J435982 | ||
| Google maps: | 54.81152,-5.76792 | ||
| County: | Council area: | Mid & East Antrim Borough Council | |
| Period: | Cretaceous, Tertiary | ||
| Site Description | |
|---|---|
| Introduction: | |
Quarrying operations at Magheramorne were already underway at the time of the first Geological Survey of Ireland in 1867. Field notes record a thickness of 20m (65 feet) of chalk in the quarry but also note that the thickness of basalt lava flows overlying the top surface of the chalk was already 14m (45 feet). Production of chalk continued until 1980 when quarrying ceased and the works finally closed in 2000. Since then the rock processing machinery and storage facilities, which are located on the north side of the Larne-Belfast road and railway line, have been moth-balled on a care and maintenance basis. Apart from the faces, up to 120m high, surrounding the deep and now partly flooded quarry site, the most obvious result of the quarrying operations is the waste dump of largely basalt rock that extends for about 1.5km into Larne Lough. A subsequent proposal to use the quarry as a disposal site for waste from Belfast was refused. However, a more recent application to site a new housing development at the western end of the waste dump area, and concurrently to develop leisure facilities within the confines of the quarry, has been approved. | |
| Description: | |
Site Geology: Hibernian Greensands Formation: In Magheramorne Quarry the oldest strata reported are just over 3m of grey and yellow calcareous mudstones and sandstones and green glauconitic sandstones of the Late Cenomanian to Early Santonian Hibernian Greensands Formation. However, due to flooding in the quarry, these strata and the lower levels of the succeeding Ulster White Limestone Formation are now submerged. Ulster White Limestone Formation: A measured thickness of 31 m of Late Santonian to Early Campanian chalk of the Ulster White Limestone Formation exposed in the quarry was divided by Fletcher (1977) into the Cloghfin Sponge Beds Member at the base, overlain by the Creggan Chalk, Boheeshane Chalk, Larry Bane Chalk and Ballintoy Chalk with the Glenarm Chalk at the top of the sequence (Figures 2 and 3). Clay-with-Flints: Although exposures of the Clay-with-Flints are found all along the inclined top surface of the chalk, forming the main face in the lower part of the quarry, none of them are easily and safely accessed. The top surface of the chalk is inclined eastwards at between 5-10o and in places shows considerable relief, representing pronounced karst topography that developed prior to the extrusion of the first basalt lava flows. Over a distance of about 400m, its topography changes from an almost planar surface at the eastern end of the south face of the quarry into a spectacular two-dimensional terrain of pinnacles and dolines with a relief of more than 15m (Photograph 41). Antrim Lava Group: The remainder and upper part of the quarry is formed of 5 basalt lava flows of the Lower Basalt Formation of the Palaeogene Antrim Lava Group with a total thickness of about 70m. Individual flows range in thickness from 8m to 30m and the basalt rock quarried in pursuit of the chalk was then removed to form the area of reclaimed land in Larne Lough. The Clay-with-Flints detail: Despite the long linear outcrop of the Clay-with-Flints in Magheramorne Quarry, few sections in the bed are safely accessible (Photograph 42). Nevertheless, a measured section at the south end of the cliff line revealed a maximum thickness of about 2.75m of Clay-with-Flints partially infilling a pothole in the chalk surface (Figure 29). This particular pothole clearly was an original feature of the chalk land surface. However, it is likely that it also subsided during and after accumulation of the Clay-with-Flints as the different layers that constitute the Clay-with-Flints show curvilinear contact surfaces and thin towards, but do not disappear at, the margins of the depression. In this particular case the amount of material of the Clay-with-Flints that was available did not completely fill the depression. Thus the base of the lowest basalt lava flow completed that process before subsuming the adjacent chalk pillars which were not covered by the Clay-with-Flints. Unusually, at the western end of the south face of the quarry, some of the deepest dolines appear to be completely filled by basalt lava with no evidence of any material from the Claywith-Flints being present. | |
| Conclusions: | |
Although no detailed analyses of the Clay-with-Flints at Magheramorne Quarry are available, the presence, in hand specimen, of numerous lapilli and pumiceous clasts is clear evidence of the volcaniclastic origin of this deposit. | |
| Notes: | |
The full series of Clay-with-Flints records is as follows: Record no. 1300 Introduction to Clay-with-Flints of Northern Ireland Record no. 1301 Belshaw’s Quarry – Clay-with-Flints Record no. 1302 Gibson’s Quarry, Portadown – Clay-with-Flints Record no. 1303 Devlin’ Quarry, Moneymore – Clay-with-Flints Record no. 1304 Glenshane Pass – Clay-with-Flints Record no. 1305 Donald’s Hill – Clay-with-Flints Record no. 1306 Tircrevan Burn – Clay-with-Flints Record no. 1307 Ballycastle – Clay-with-Flints Record no. 1308 Demesne Quarry, Glenarm – Clay-with-Flints Record no. 1309 Magheramorne Quarry, Larne – Clay-with-Flints Record no. 1310 Bellevue, Belfast, Co Antrim – Clay-with-Flints Record no. 1311 Soldierstown Quarry, Moira – Clay-with-Flints | |
| Keywords | |
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| Rocks: | Chalk, Clay, Flint, Basalt |
| Access | |
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| Approach: | Private land. Disused quarry (Photograph 40), Ballylig Townland [Grid Square: J43 98], southwest side of Larne Lough at Magheramorne, 5.3km SE from Larne railway station and 3.3km ESE from Glynn, Co. Antrim (Figures 27 and 28). |
| Restrictions: | Private land |
| Record type: | ESCR report | ||
| Entered by: | I J Enlander | ||
| Last updated: | 28 Mar 2019 | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Magheramorne Quarry, Larne – Clay-with-Flints, County , site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=1309. Accessed on 2026-11-06. |
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