Uploaded on:
2009-03-11 05:37:50.0
Type:
Digital Asset
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375.30 KB
Dimensions:
1000 x 663 pixels
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P number: P531446
Caption: Photomicrograph of limestone. Light: PPL. Magnification: x2.5. Quarry, 1450 yards south by west of Achvarasdal, Reay, Caithness, Scotland
Description: A pale buff, compact limestone, composed essentially of rather turbid calcite with grain size 0.01-0.15 mm across, with scattered larger grains. This specimen is Middle Old Red Sandstone (Devonian) in age. BGS Sample Number SL 282. British Geological Survey Petrology Collection sample number S 35911. Angular quartz, up to 0.15 mm grain size, white mica, in flakes generally 0.1 mm long, and potash-feldspar are abundantly distributed in the rock and are concentrated along thin laminae coloured dark by bituminous matter. Following dissolution of the sample in cold dilute hydrochloric acid, the insoluble residue contains chlorite, hornblende and clay found as accessory constituents, and potash-feldspar which has developed crystal faces during recrystallisation. In summary the rock is a fine-grained muddy and bituminous limestone with strong bedding lamination.
Date taken: Sun Jun 25 00:00:00 GMT 1905
Photographer: Unknown
Copyright statement: Unknown
Orientation: Landscape
Size: 375.30 KB; 1000 x 663 pixels; 85 x 56 mm (print at 300 DPI); 265 x 175 mm (screen at 96 DPI);
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