| P number: | P527990 |
|---|---|
| Caption: | Photomicrograph of flaggy limestone. Light: PPL. Magnification: x2.5. Stream 4 miles east-south-east of Halkirk station, Caithness, Scotland. |
| Description: | Black flaggy limestone with thin lamination in shades of grey. This specimen is Middle Old Red Sandstone (Devonian) in age. BGS sample number SL 163. British Geological Survey Petrology Collection sample number S 34850. Photomicrograph details: Light: PPL, Magnification: x2.5. In thin section alternating bands are seen to consist of: (1) coarser bands containing rhombs of dolomite up to 0.1 mm across, angular quartz grains, usually in subordinate proportion but sometimes abundant, plagioclase and scarce muscovite flakes, in a matrix of shapeless calcite obscured by disseminated bitumen or bituminous clay; (2) thin bands and lenticles of finely granular carbonate containing rhombs of dolomite, but little quartz or bituminous matter; (3) films of reddish-brown almost opaque bituminous clay. In places these films almost coalesce to form thin bands of gritty, calcareous bituminous shale. The image has a yellowish colour due to the alteration of the Canada Balsam in which the thin section is mounted. |
| Date taken: | Sun Jun 25 00:00:00 GMT 1905 |
| Photographer: | Unknown |
| Copyright statement: | Unknown |
| Orientation: | Landscape |
| Size: | 451.79 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