P number: | P528002 |
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Caption: | Photomicrograph of limestone. Light: PPL. Magnification: x10. South side of Bay of Fladdabister, Shetland Isles, Scotland. |
Description: | A grey crystalline limestone with thin dark seams. This specimen is Shetland metamorphic in age. BGS sample number SL 184. British Geological Survey Petrology Collection sample number S 34947. Photomicrograph details: Light: PPL, Magnification: x10. The rock is composed essentially of anhedral grains of calcite showing close glide twinning. In thin section the grains, which are about 1.0 mm long, interlock, or are cemented by finely granular calcite which is due to trituration by shearing; similar fine calcite cuts through the larger calcite grains and also forms thin parallel seams. Quartz in grains 0.1-0.2 mm across, and small flakes of muscovite are abundant accessories. A little finely divided opaque mineral is present throughout the sample, the larger grains being recognizable as oxidized iron-ore, probably pyrite. Apatite and tourmaline are accessory minerals. |
Date taken: | Sun Jun 25 00:00:00 GMT 1905 |
Photographer: | Unknown |
Copyright statement: | Unknown |
Orientation: | Landscape |
Size: | 343.24 KB; 1000 x 663 pixels; 85 x 56 mm (print at 300 DPI); 265 x 175 mm (screen at 96 DPI); |
Average Rating: | Not yet rated |
Categories: | Unsorted Images |
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