| P number: | P521285 |
|---|---|
| Caption: | Rock specimen of pillow lava. Five-sixteenths of a mile north of summit of An Aird, 2.75 miles south-west of Tayvallich, Argyllshire, Scotland. |
| Description: | The sample is a fine-grained, uniform dark basic igneous ('basaltic') rock. It contains small cavities called vesicles, which represent original gas bubbles present in the molten magma when it was erupted. British Geological Survey Petrology Collection sample number EMC864. The term pillow lava refers to a particular texture of basaltic lava where the molten rock has erupted under water. The rapid chilling of the magma causes it to form a surface skin, and break off into large droplets each typically several tens of centimetres across. These 'pillows' eventually pile up to form large accumulations, known as pillow lavas. The rock is from the Tayvallich Volcanic Formation (Tayvallich Subgroup, Argyll Group, Dalradian Surpergroup, Precambrian). The formation consists of a complex interdigitation of limestones, clastic sediments and volcanic rocks. The volcanic formation consists of 2000 metres of commonly pillowed basic lavas, hyaloclastites and a variety of epiclastic volcanic rocks. |
| Date taken: | Sun Dec 01 00:00:00 GMT 2002 |
| Photographer: | McTaggart, F.I. |
| Associate: | T.S. Bain |
| Copyright statement: | NERC |
| Additional information: | EMC864 |
| Orientation: | Landscape |
| Size: | 267.69 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: | Best of BGS Images/ Geological structures |
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