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Earth Science Conservation Review
| Slieve Gullion Ring - Slieve Gullion | Armagh |
| Site number: | 1125 | ||
| ESCC: | EO | ||
| Locality Type: | Crag, Crags | Status: | ASSI |
| Grid Reference: | J020198 Centroid | ||
| Google maps: | 54.11765,-6.44012 | ||
| County: | Armagh | Council area: | Newry, Mourne & Down District Council |
| Period: | Tertiary | ||
| Stages: | Palaeogene | ||
| Lithostrat: | Slieve Gullion Complex | ||
| Site Description | |
|---|---|
| Description: | |
The dolerite of layer 10 is a sill intrusion into the acid rocks of the Slieve Gullion summit area according to both Reynolds and Bailey. The basal zone may have contained rafts of granitic (country) rock. Granophyre also occurs as narrow, vertical pipes cutting the dolerite. These may be connected to veins or sheet- like masses of granophyre below but show blind terminations upwards. The composition of the pipe-rock varies from normal granophyre to patchy and homogeneous hybrid (granite/dolerite) from base to top of the pipe. Both curvilinear and rectilinear net-veining occur in the dolerite and some good 'pillow-like' structures can be found in the main cliff above the summit car park. | |
| Importance: | |
All the features noted above are good evidence for the simultaneous existence of both basic and acid magma. The melting of pre-existing acid igneous rock by basaltic magma can be inferred; the chilling of the basic magma against the cooler acid melt can be demonstrated, as can the hybridisation of the two melts. The granophyre and hybrid pipes are unique to Slieve Gullion and restricted to layer 10, and can be found at a number of localities around the higher slopes of the mountain. The rise of less dense granophyric magma into denser basaltic magma was probably triggered by the formation of even more buoyant gas bubbles in the acid melt. | |
| Notes: | |
For reference list see; Key site 1118 - Slieve Gullion Ring - Overview | |
| Keywords | |
|---|---|
| Rocks: | Dolerite, Granite, Granophyre |
| Structures: | magma mixing, net veins, pipes, sill |
| Relations: | Intrusion |
| Access | |
|---|---|
| Approach: | The crags overlook the forest scenic drive SW of the summit of Slieve Gullion. The forest drive may be accessed from the SW and SE sides of Slieve Gullion. |
| Map(s): | For site location see the 1:50,000 O.S. Sheet 29 (The Mournes) Discoverer Series. | ||
| Record type: | ESCR report | ||
| Entered by: | E M Porter | ||
| Enlander, I., Dempster, M. & Doughty, P., 2026. Slieve Gullion Ring - Slieve Gullion, County Armagh, site details. [In] Earth Science Conservation Review. https://www.habitas.org.uk/escr/site.php?item=1125. Accessed on 2026-11-08. |
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