| P number: | P527962 |
|---|---|
| Caption: | Photomicrograph of Loch Tay Limestone. Light: XPL. Magnification: x2.5. Askomill Quarry, 4 miles east-north-east of Campbeltown, Argyllshire, Scotland. |
| Description: | Banded coarse- and fine-grained limestone. This specimen is Dalradian Supergroup (Precambrian) in age. BGS sample number SL 128. British Geological Survey Petrology Collection sample number S 34576. Photomicrograph details: Light: XPL, Magnification: x2.5. The coarse bands which show curved cleavage surfaces of blackish calcite are in thin section composed of large irregular grains of calcite with patchy and undulose extinction. The finer-grained bands are composed of grains of calcite of irregular size and shape, very numerous clear and dust-impregnated grains of albite, 0.1 mm, and abundant opaque granular material sometimes recognisable as pyrite. Quartz and potash-feldspar are also present. Scattered grains of feldspar and opaque granules occur also in the coarse-grained bands. The black residue from digestion of the sample in concentrated hydrochloric acid is mainly dust-impregnated albite and shapeless black grains, many of which are pyrite. On prolonged roasting in a crucible the residue becomes pale grey and the discharge of colour indicates that much carbon is present. |
| Date taken: | Sun Jun 25 00:00:00 GMT 1905 |
| Photographer: | Unknown |
| Copyright statement: | Unknown |
| Orientation: | Landscape |
| Size: | 400.41 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 |
Loading...
Loading...
Reviews
There is currently no feedback