| Site Type: | Crag, Crags | | Site Status: | ASSI | | Council area: | Newry, Mourne & Down District Council | | Grid Reference: | J020198 | | Bing maps: | 54.11765,-6.44012 | | Google maps: | 54.11765,-6.44012 | | Rocks |
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| Rock Age: | Tertiary (Palaeogene) | | Rock Name: | Slieve Gullion Complex | | Rock Type: | Dolerite, Granite, Granophyre | | Interest |
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| Other interest: | magma mixing, net veins, pipes, sill, Intrusion |
| Summary of site: |
| This account describes layer 10, one of 13 layers forming the central mass of Slieve Gullion. The context for this site is given in the Slieve Gullion Ring – Overview, site1118. | | Layer 10 is exposed south west of the summit of Slieve Gullion and is a dolerite (medium-grained, dark coloured rock of basaltic composition) injected horizontally into the local host rock, the much older Newry granodiorite. Narrow vertical pipes of granophyre, a type of granite, and mixed hybrids with dolerite terminate blindly in this layer and probably originate in veins and sheets below. Networks of veins permeate the dolerite and rounded pillow-like masses of dolerite can be seen in the cliff above the summit car park. | | This site shows that basic and acidic magmas co-existed, that the dolerite chilled against the cooler granophyre and the two rocks mixed in places to form hybrids. The blind pipes are unique to layer 10. The pillow-like masses are due to bulging on the interface between the two magmas. | | This site is an essential component of our overall understanding of the Slieve Gullion Ring complex and should be designated. |
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