| P number: | P524315 |
|---|---|
| Caption: | Photomicrograph of limestone. Light: XPL, Magnification x 2. 300 m. 265 degrees from Dunardry Cottage, Aberfoyle, Perthshire. |
| Description: | The image is a thin section photomicrograph of a limestone from the Grampian Highlands of Scotland. The image is taken under conditions of crossed-polarized light in order to highlight the various mineral components of the rock. British Geological Survey Petrology Collection sample number S 98574. Light: XPL, Magnification x 2. Light: XPL, Magnification x 2. Several different generations of carbonate are visible in the rock. A band of early, darker grey coloured limestone has been fractured and penetrated by veins of a lighter colour which correspond to a large patch of lighter calcite. This appears to represent a second generation of carbonate in the sample which may result from deformation and recrystallization during a metamorphic event. The ability of a petrological microscope to view a thin section under crossed-polarizing light is a powerful tool in petrographic studies. It induces an interference pattern of light within the mineral components of the rock, and different mineral types show different colours, termed birefringence. This effect can be used to distinguish and identify different mineral types. For example, muscovite mica has a particularly high birefringence, producing very brightly-coloured crystals, whilst quartz has a low birefringence and is typically white or grey under crossed-polarized light. |
| Date taken: | Wed Jan 01 00:00:00 GMT 2003 |
| Photographer: | Hyslop, E.K. |
| Copyright statement: | NERC |
| X longitude/easting: | 251450 |
| Y latitude/northing: | 700220 |
| Coordinate reference system, ESPG code: | 27700 (OSGB 1936 / British National Grid) |
| Orientation: | Landscape |
| Size: | 349.30 KB; 1000 x 667 pixels; 85 x 56 mm (print at 300 DPI); 265 x 176 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Unsorted Images |
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