| P number: | P521383 |
|---|---|
| Caption: | Rock specimen of augite andesite tuff. Bail Hill anticline, 2.5 miles north-west of Sanquar, Dumfriesshire, Scotland. |
| Description: | This sample is a complex mixed volcanic rock containing fragments of a fine-grained basic igneous rock (like basalt) within a porphyritic andesite containing prominent crystals of orange feldspar and black reflective augite. British Geological Survey Petrology Collection sample number EMC3622. The Bail Hill complex is a 1.8 km. thick series of volcanic rocks near Sanquhar comprising lavas and pyroclastic rocks. The rocks referred to by early workers as andesites are in fact now termed mugearite and hawaiite, and are typical of a submarine sea-mount volcano, such as that seen today in Hawaii. The Bail Hill Volcanic Group (Ordovician, Caradoc age) is the largest volcanic complex exposed within the Ordovician succession in the Southern Uplands. It has two formations the older Cat Cleugh Formation of mostly autobrecciated pyroxenous basalts and the Peat Rig Formation which comprises the bulk of the volcanic pile. It is a 900 metres thick sequence of trachybasalt, trachyandesite lava, lapilli-tuff, volcanic breccia and volcanic sandstone. |
| Date taken: | Sun Dec 01 00:00:00 GMT 2002 |
| Photographer: | McTaggart, F.I. |
| Associate: | T.S. Bain |
| Copyright statement: | NERC |
| Additional information: | EMC3622 |
| Orientation: | Landscape |
| Size: | 296.35 KB; 1000 x 775 pixels; 85 x 66 mm (print at 300 DPI); 265 x 205 mm (screen at 96 DPI); |
| Average Rating: | Not yet rated |
| Categories: | Unsorted Images |
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