| P number: | P528017 |
|---|---|
| Caption: | Photomicrograph of Charlestown Main Limestone, 2-5 ft above dolerite sill. Light: PPL. Magnification: x2.5. Mine, at north-west end of Roscobie Quarry, Fifeshire, Scotland. |
| Description: | A grey limestone with a greenish tinge, with rough fracture and altered aspect. This specimen is Carboniferous Limestone Series in age. BGS sample number SL 226. British Geological Survey Petrology Collection sample number S 35084. Photomicrograph details: Light: PPL, Magnification: x2.5. The limestone is composed of a mosaic of clear granular calcite of varying grain size (0.01-0.2 mm). In this are scattered numerous relics of crinoid columnals and shells. The shape of the columnals is retained but the plates are recrystallized to granular aggregates. The shape of the shells is very largely lost through recrystallization. Small black grains are scattered in accessory proportions in the rock and larger grains of pyrite are scarce. The rock contains a considerable quantity of clear interstitial substance amongst the calcite mosaic. This is an aggregate of very small fibres and scales insoluble in cold dilute HCl and appears as a greenish clay when the calcite is dissolved out. When thus separated the colour of the mineral is in general pale greenish, but often yellow and occasionally brown; from its optical properties it seems to be an antigoritic chlorite. |
| Date taken: | Sun Jun 25 00:00:00 GMT 1905 |
| Photographer: | Unknown |
| Copyright statement: | Unknown |
| Orientation: | Landscape |
| Size: | 370.35 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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