| P number: | P527963 |
|---|---|
| Caption: | Photomicrograph of Islay Limestone. Light: XPL. Magnification: x2.5. Leorin Quarry, two and one eighth miles north by west of Port Ellen, Islay, Argyllshire, Scotland. |
| Description: | Grey fine-grained limestone, laminated and cut by lines of calcite. This specimen is Dalradian Supergroup (Precambrian) in age. BGS sample number SL129. British Geological Survey Petrology Collection sample number S 34577. Photomicrograph details: Light: XPL, Magnification: x2.5. The rock contains schistose granular calcite, 0.05 mm grain size, the schistosity being marked by elongation of the calcite grains, by trains of opaque dark mineral matter and by occasional elongated grains of quartz. Laminae of coarser granular calcite, 0.3 mm grain, appear parallel to the schistosity and show ellipsoidal swellings which occasionally contain large turbid grains of calcite with undulose extinction. These coarser laminae pass without change of the type of calcite into cross-cutting veins. Granular quartz occurs in the coarser laminae and idiomorphic quartz in the veins. It seems likely that the coarse laminae were recrystallized at the time of the cross-cutting veins by permeation of the solutions along lines of weakness, perhaps produced by the presence of relict augen of coarser calcite. A limestone recrystallized under stress and showing foliation by alternation of bands of coarser and finer-grained grain-foliated structure which are parallel to a schistosity produced by elongation of calcite grains and trains of dark mineral matter. |
| Date taken: | Sun Jun 25 00:00:00 GMT 1905 |
| Photographer: | Unknown |
| Copyright statement: | Unknown |
| Orientation: | Landscape |
| Size: | 392.73 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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