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Uploaded on:
11/03/2009 05:33:54
Digital Asset
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169.60 KB
1000 x 775 pixels
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P number: P521517
Caption: Mineral specimen of onyx agate quartz amygdale. Dunure Railway, Brown Carrick Hills, Ayrshire.
Description: The specimen is an onyx agate quartz amygdale. It consists of an outer rim of fine banded agate and onyx with a core of quartz. The quartz crystals are projecting into an open 'drusy' cavity or geode. British Geological Survey Petrology Collection sample number E 3299A. The amygdale formed as a result of hydrothermal fluids percolating through basaltic volcanic rocks, which precipitated minerals in open cavities or vesicles, originally formed as gas bubbles. This specimen is from the Lower Old Red Sandstone (Devonian) Maybole Volcanic Series. There is a large volcanic pile in the Carrick Hills. It consists of a 300 to 450 metres thick sequence of olivine-basalts and hypersthene-andesites resting on a thick sequence of clastic sediments and is overlain unconformably by Upper Devonian strata.
Date taken: 01/01/2003
Photographer: Unknown
Copyright statement: NERC
Orientation: Landscape
Size: 169.60 KB; 1000 x 775 pixels; 85 x 66 mm (print at 300 DPI); 265 x 205 mm (screen at 96 DPI);
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Categories: Best of BGS Images/ Rocks and minerals  


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