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Uploaded on:
14/02/2009 07:02:04
Digital Asset
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334.47 KB
1000 x 678 pixels
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P number: P007662
Old photograph number: A13448
Caption: Craig-y-cwm, rear wall.
Description: Craig-y-cwm, rear wall. Calcrete beneath fining-upwards cycle of pebbly grit. The Quartz Conglomerate Group (Upper Old Red Sandstone) contains a dull red, trough and festoon cross-bedded pebbly and gritty sandstone, laterally equivalent to coarse quartz pebble conglomerates. The grit is 1.6 m. - 2.3 m. thick at Craig-y-cwm with a basal 0 - 0.2 m. lag with cornstone clasts. Towards the top, thin discontinuous beds of planar cross-laminated medium-grained green sandstone occur. The grit is interpreted as the channel-fill of a braided river with scour and fill; as current activity wanes, slip faces on the bar margins accumulate sandstone. The grit irregularly but sharply overlies a lenticular concretionary cornstone, 0.22 m. - 0.68 m. thick, interpreted as an immature calcrete (pedogenic carbonate). The calcrete rests on a calcareous poorly-bedded green sandstone with decomposed marl clasts on the cross-bedded foresets.
Date taken: 01/01/1978
Photographer: Pulsford, J.M.
Copyright statement: NERC
Acknowledgment: This image was digitized with grant-in-aid from JIDI the JISC Image Digitization Initiative
X longitude/easting: 328270
Y latitude/northing: 208840
Coordinate reference system, ESPG code: 27700 (OSGB 1936 / British National Grid)
Orientation: Landscape
Size: 334.47 KB; 1000 x 678 pixels; 85 x 57 mm (print at 300 DPI); 265 x 179 mm (screen at 96 DPI);
Average Rating: Not yet rated
Categories: Unsorted Images, Geoscience subjects/ Sedimentary features/ False-bedding, cross, current and dune  


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