| P number: | P521392 |
|---|---|
| Caption: | Rock specimen of diabase porphyry. North end of Stockingray Bay, 5 miles south of Girvan, Ayrshire, Scotland. |
| Description: | The sample is a basic igneous rock with striking elongate laths of feldspar within a dark fine-grained igneous groundmass. The feldspars show alignment of their long axes which may indicate the direction of flow of the volcanic magma before it cooled and solidified. British Geological Survey Petrology Collection sample number EMC3033. The Ballantrae Igneous Complex contains a range of igneous rock types which form an ophiolitic assemblage, that is a group of rock types normally found only in oceanic crust. In general terms, the complex consists of belts of serpentinite rocks, bands of lavas, and abundant igneous intrusions. The serpentinites are altered olivine and pyroxene-rich rock types, classed as ultramafic (or ultrabasic). The intrusions are generally gabbros and dolerites, whilst the volcanic rocks are classed as tholeiitic basalts, many of which are submarine pillow basalts. The lava is part of the Ballantrae Igneous Complex. The complex is a group of spilitic lavas and pyroclastic rocks with associated cherts and fossiliferous shales and a number of major and minor intrusions. It is of Arenig (Ordovician) age and is thought to be oceanic crust 'obducted' i.e. thrown up at a destructive plate margin. |
| Date taken: | Sun Dec 01 00:00:00 GMT 2002 |
| Photographer: | McTaggart, F.I. |
| Associate: | T.S. Bain |
| Copyright statement: | NERC |
| Additional information: | EMC3033 |
| Orientation: | Landscape |
| Size: | 254.48 KB; 1000 x 775 pixels; 85 x 66 mm (print at 300 DPI); 265 x 205 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Unsorted Images |
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