| P number: | P524228 |
|---|---|
| Caption: | Photomicrograph of granodiorite. Light: XPL, Magnification x 2. 490 yards south, 19 degrees east of Tigh Mor na Seilge summit, north of Loch Cluanie, Invernessshire. |
| Description: | The image is a photomicrograph of a granodiorite taken under cross-polarized light. British Geological Survey Petrology Collection sample number S 56621. Light: XPL, Magnification x 2. Light: XPL, Magnification x 2. The rock has a coarse-grained texture consisting of interlocking crystals dominated by large plagioclase feldspars which are identified by their distinctive grey birefringence colours (ranging from white to black) and lamellar twinning. Amphibole and mica have brighter birefringence colours, seen as varying shades of greens and browns. This specimen, found 490 yards south, 19 degrees east of the Tigh Mor na Seilge summit is from the Cluanie Intrusion, one of the younger Caledonian 'Newer Granites' and has been dated at c. 425 Ma. The Cluanie Intrusion is a variably porphyritic hornblende biotite granodiorite that covers an area of 18 square kilometres. It shows displacement of its envelope with the strike and dip of the Moine rocks conforming to the attitude of the igneous contact. Veins of Cluanie granodiorite cut other rocks such as a suite of felsic porphyrites. |
| Date taken: | Wed Jan 01 00:00:00 GMT 2003 |
| Photographer: | Hyslop, E.K. |
| Copyright statement: | NERC |
| X longitude/easting: | 213600 |
| Y latitude/northing: | 815500 |
| Coordinate reference system, ESPG code: | 27700 (OSGB 1936 / British National Grid) |
| Orientation: | Landscape |
| Size: | 259.24 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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