| P number: | P521340 |
|---|---|
| Caption: | Rock specimen of trachyte. Weak Law, 1.5 miles north-north-west of Dirleton, Haddingtonshire, Scotland. |
| Description: | The sample is a dark grey, fine-grained trachytic rock with a siliceous appearance, strongly marked by a series of concentric rings. The rings appear to represent a series of 'fronts' of iron oxidation, probably related to fluids which have migrated through the rock. British Geological Survey Petrology Collection sample number EMC2495. The earliest widespread Carboniferous volcanic activity in the Midland Valley is of early Visean age. Thick lava sequences were developed within the Lower Calciferous Sandstone Measures of East Lothian and Edinburgh City and thinner developments may be traced south-westwards towards Carstairs. In East Lothian the volcanic sequence of the Garleton Hills is up to 520 m. thick. The eruptions that formed the Carboniferous lavas in Central Scotland are thought to have been from relatively small and short-lived central volcanoes, the remains of which are preserved in some areas as vents and plugs, usually of less than 500 m. diameter, surrounded by proximal lava flows and pyroclastic features. |
| Date taken: | Sun Dec 01 00:00:00 GMT 2002 |
| Photographer: | McTaggart, F.I. |
| Associate: | T.S. Bain |
| Copyright statement: | NERC |
| Additional information: | EMC2495 |
| Orientation: | Portrait |
| Size: | 215.56 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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