| P number: | P527989 |
|---|---|
| Caption: | Photomicrograph of limestone in 'Boulder Beds'. Light: PPL. Magnification: x2.5. South-west of the 'Fallen Stack', Portgower, Sutherland, Scotland. |
| Description: | A pale grey limestone containing numerous shells. This specimen is Jurassic in age. BGS sample number SL 162. British Geological Survey Petrology Collection sample number S 34849. Photomicrograph details: Light: PPL, Magnification: x2.5. In thin section large and small echinodermal and shell fragments and poorly assorted sand grains are cemented by calcite. Over most of the section quartz and cementing calcite are in approximately equal proportion. The calcite is partly fine-grained and turbid but more generally coarsely recrystallized and often poikilitic. The sand grains are angular and rarely reach 1 mm in size. They are mostly of quartz which is often strained but include microcline and crushed quartz-rock, scarce chert and cellophane. The rock shows a poikilocrystallic structure, where calcite forms large shapeless crystals enclosing angular grains of quartz and feldspar and shell fragments. |
| Date taken: | Sun Jun 25 00:00:00 GMT 1905 |
| Photographer: | Unknown |
| Copyright statement: | Unknown |
| Orientation: | Landscape |
| Size: | 336.64 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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