| P number: | P521322 |
|---|---|
| Caption: | Rock specimen of vesicular andesite. Shore cliff, near St. Cyrus, 4 miles north of Montrose, Kincardineshire, Scotland. |
| Description: | The sample is a spectacular example of a vesicular basic igneous rock. The rock is a fine-grained dark red andesite which contains a series of highly elongate lensoid vesicles partially infilled by pale white and greenish minerals. Stretching-out and alignment of vesicles may occur as the molten rock flows during its extrusion or eruption, producing a type of flow texture. British Geological Survey Petrology Collection sample number EMC1766. A vesicular rock is one containing vesicles, which are small spherical cavities formed in volcanic lavas where gas bubbles become trapped during solidification of the rock. Some rock types are extremely rich in vesicles, such as pumice which represents the gas-rich 'froth' close to the surface of a molten lava. The andesite forms part of the Lower Devonian calc-alkaline igneous province. Most of the volcanic successions consist of basaltic or andesitic lavas. |
| Date taken: | Sun Dec 01 00:00:00 GMT 2002 |
| Photographer: | McTaggart, F.I. |
| Associate: | T.S. Bain |
| Copyright statement: | NERC |
| Additional information: | EMC1766 |
| Orientation: | Landscape |
| Size: | 289.63 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: | Best of BGS Images/ Geological structures |
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