| P number: | P521289 |
|---|---|
| Caption: | Rock specimen of folded gneiss. Railway cutting, south of Black Croft, River Falloch, Perthshire, Scotland. |
| Description: | The sample is a superb example of a folded gneiss, typical of the Scottish Highlands. It is a semipelitic gneiss (a metamorphosed siltstone) which contains distinct bands or veins of quartz which have been deformed and folded under conditions of high temperature and pressure, to produce a series of parallel or concentric folds. British Geological Survey Petrology Collection sample number EMC1474. Quartz veins such as these have probably formed whilst the rock was undergoing regional metamorphism, when fluid under high temperature was carrying solutions of dissolved minerals which migrated through the rock, and were precipitated as a series of parallel lenses or veins. Many ore deposits are associated with hydrothermal quartz veins, where rare minerals or elements such as copper, silver and gold are also transported through the rock in such hydrothermal solutions. |
| Date taken: | Sun Dec 01 00:00:00 GMT 2002 |
| Photographer: | McTaggart, F.I. |
| Associate: | T.S. Bain |
| Copyright statement: | NERC |
| Additional information: | EMC1474 |
| Orientation: | Portrait |
| Size: | 211.75 KB; 775 x 1000 pixels; 66 x 85 mm (print at 300 DPI); 205 x 265 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Best of BGS Images/ Geological structures |
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