| P number: | P552838 |
|---|---|
| Caption: | Dolomite. Stream 5/6th mile south of Keoldale, about 75 yards upstream from road. Sutherland. |
| Description: | The analyses were made on composite samples of which the four specimens described below are representative, but the proportions of the various types may have differed in the samples supplied for Anal. M 23799 and Anal. GS 1203 respectively. S 34842. A fine-grained, uniform dolomite of grain size about 0.1 mm. Local patches of coarser grain with occasional limonitic fillings along the cleavages occur. Stylolitic films of limonitic clay are present but scarce and there are traces of quartz. Dolomite, fine-grained, mosaic. S 34843. Bedded dolomite, with alternating laminae of 0.01 to 0.05 mm grain containing numerous streaky impregnations of limonite and occasional laminae of chert and ferruginous material. Small angular grains of quartz are numerous and the rock probably contains some clay. Dolomite, luteous, pelitomorphic to micrograined, taxichnic, thin-bedded. S 34844. Fine-grained, sandy dolomite with some bands of slightly coarser material; composed of grains of dolomite, about 0.03 mm average grain, with subordinate quartz and alkali-feldspar in angular grains up to 0.1 mm long, and some muscovite in small thin flakes. The rock is cut by thin veins of coarser dolomite. Dolomite, luteous to arenaceous, fine-grained, taxichnic, mosaic. S 34845. Dolomite of grain varying between 0.03 and 0.3 mm. There is a local cement of limonite which is only enough to form coatings to the dolomite grains. Limonite is present also along lines of fracture. The variation in grain-size is abrupt so that the rock has a brecciated or nodular appearance in hand specimen, but enclosure of limonitic dust trains in the large dolomite grains suggests that recrystallization to coarse dolomite is later than the fracturing of the rock. Chert occurs in sporadic vacuoles. Dolomite, varigrained, breccioid, mosaic. SL0175. Britrocks S34842. Magnification x40. Light PPL. |
| Date taken: | Wed Jan 21 00:00:00 GMT 2004 |
| Photographer: | Sutherland, A. |
| Copyright statement: | NERC |
| Additional information: | Description from: Limestones of Scotland: chemical analyses and petrography. Edinburgh : HMSO, 1956. 10 minutes in Logwood stain. |
| Orientation: | Landscape |
| Size: | 297.34 KB; 1000 x 750 pixels; 85 x 64 mm (print at 300 DPI); 265 x 198 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Unsorted Images |
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