| P number: | P521370 |
|---|---|
| Caption: | Rock specimen of brecciated lava contact with sandstone. Shore between Lochan and Castle Port, 6 miles north of Girvan, Ayrshire, Scotland. |
| Description: | The sample is an unusual mixed rock containing the junction between a sandstone and a basic igneous lava. The sandstone is a fine-grained brownish-grey colour and has been injected by a dark purplish-coloured lava containing abundant small amygdales. Small fragments of the sandstone have broken away and become incorporated into the lava. British Geological Survey Petrology Collection sample number EMC3215. This interesting rock would be described as a 'contact rock' because it shows the contact of a sandstone and an igneous rock. The igneous lava would have been erupted or injected into the pre-existing sediment, causing it to split and fragment with small pieces becoming incorporated into the lava. It is common for such sedimentary rocks to be affected by the high temperatures of the molten magma, which can result in changes in texture and mineralogy, termed 'contact metamorphism'. The Devonian rocks were laid down in an internal basin within a large continent. The basin lay between the mountains of the Caledonian Orogeny in the north and the newly formed Southern Uplands in the south. The sediments are of continental facies and are associated with extensive piles of andesitic and basaltic lavas. In the Maybole area and to the coast there is a lower sedimentary sequence (mostly sandstones) at least 420 metres thick overlain by lavas. |
| Date taken: | Sun Dec 01 00:00:00 GMT 2002 |
| Photographer: | McTaggart, F.I. |
| Associate: | T.S. Bain |
| Copyright statement: | NERC |
| Additional information: | EMC3215 |
| Orientation: | Landscape |
| Size: | 265.29 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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