| P number: | P528023 |
|---|---|
| Caption: | Photomicrograph of pseudobreccia limestone. Light: PPL. Magnification: x2.5. St. Monans shore east of harbour, Fifeshire, Scotland. |
| Description: | Dark brownish-grey limestone with conchoidal fracture, speckled with small crinoid columnals and impregnated with pyrite in bulbous growths from which small bud-like aggregates extend. This specimen is Carboniferous Limestone Series in age. BGS sample number SL 236. British Geological Survey Petrology Collection sample number S 35239. Photomicrograph details: Light: PPL, Magnification: x2.5. The limestone is composed of very fine debris through which foraminifera and fragments of shells and crinoid are scattered. The matrix is recrystallized in fine-grained calcite (0.02 mm grain size), and the outlines of the fossils are in part lost. The pyrite appears as a spongy aggregate enclosing some unaltered fossil fragments and enters as an impregnation along with mainly carbonaceous matter, into some foraminifera and shell and polyzoan fragments. A crinoid columnal is seen in process of replacement by pyrite. Examination of this sample under reflected light shows organic structure in the opaque pyrite aggregate. The pyritic growths are thus replacement deposits in the limestone. |
| Date taken: | Sun Jun 25 00:00:00 GMT 1905 |
| Photographer: | Unknown |
| Copyright statement: | Unknown |
| Orientation: | Landscape |
| Size: | 331.39 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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