| P number: | P524424 |
|---|---|
| Caption: | Photomicrograph of olivine basalt. Light: XPL, Magnification x 2. North of Tallabric, Sanday, Invernessshire. |
| Description: | The image is a photomicrograph of a thin section of a basalt, taken under crossed-polarized light in order to distinguish between the different mineral components of the rock. British Geological Survey Petrology Collection sample number S 97092. Light: XPL, Magnification x 2. Light: XPL, Magnification x 2. The rock is dominated by phenocrysts of feldspar and olivine within a fine-grained 'glassy' volcanic groundmass. The plagioclase feldspar forms elongate needles or laths which have variable grey colours. The brightly-coloured rounded crystals are olivine. This specimen of olivine basalt from Sanday belongs to the British Tertiary Volcanic Province and forms part of the Rum Central Igneous Complex and is part of the Canna Lava Formation. The emplacement of the complex began with acidic magmatism closely linked with ring faulting. This was followed by the layered ultrabasic and basic rocks and then finally, as the centre was unroofed the Canna Larva Formation accumulated. The Canna Lava Formation on Sanday and Canna is a succession of lavas and coarse fluviatile conglomerates up to 200 metres thick and is regarded as the best development of interbedded lavas and sedimentary rocks in the whole of the Hebridean Province. |
| Date taken: | Wed Jan 01 00:00:00 GMT 2003 |
| Photographer: | Hyslop, E.K. |
| Copyright statement: | NERC |
| X longitude/easting: | 126540 |
| Y latitude/northing: | 804380 |
| Coordinate reference system, ESPG code: | 27700 (OSGB 1936 / British National Grid) |
| Orientation: | Landscape |
| Size: | 381.45 KB; 1000 x 680 pixels; 85 x 58 mm (print at 300 DPI); 265 x 180 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Best of BGS Images/ Rocks and minerals under the microscope |
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