| P number: | P519709 |
|---|---|
| Caption: | Specimen of phonolite from Traprain Law, East Lothian, Scotland |
| Description: | The sample is a cut and polished slab of an attractive red-brown rock that could be used as a decorative stone cladding. The specimen is of Carboniferous age. British Geological Survey Petrology Collection sample number EMC 5693. The rock appears to have a relatively fine-grained groundmass but contains abundant visible crystals of pink alkali feldspar. The Traprain Law intrusion is a phonolite which forms part of a vast volcanic sequence of Carboniferous age in the Scottish Midland Valley. The greater part of the rock consists of aligned laths of alkali feldspar and nepheline which is very hard to see in the rock, even when viewed in thin section under the microscope. About 20 per cent of the rock consists of the mineral analcite, with a very small amount of sodalite. Strictly speaking, the Traprain Law rock is classified as a sodalite-bearing phonolitic analcite-trachyte. |
| Date taken: | Wed Jan 01 00:00:00 GMT 2003 |
| Photographer: | Bain, T.S. |
| Copyright statement: | NERC |
| Orientation: | Landscape |
| Size: | 230.62 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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