P number: | P212533 |
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Old photograph number: | A13480 |
Caption: | Glaciofluvial gravels, River Usk, the Whibbs, near Llancayo, Gwent. |
Description: | South-east bank of the River Usk, the Whibbs, near Llancayo. Glaciofluvial gravel, Llancayo. Erosion on the outside of a meander bend near Llancayo has created and maintained a relatively fresh face, 13.5 m. high, the basal 8.3 m. of which are cut in glaciofluvial gravels, formed as braid bars in valley train gravels. The gravels consist of crude horizontally-bedded layers with poor fining-upward cycles and some imbricate pebbles. Beds of coarse openwork gravel cemented by carbonate at the base of the cycle pass up into beds of finer gravel with a clayey and gritty sand matrix; this may represent original discharge fluctuations in a waning current, in which the suspended fines eventually settle into voids in the surface layer of gravels. Beds of medium sand near the top of the cycle probably represent deposition from a waning current on downstream slip faces of emergent bars. When a glacier melts part of its load is carried away to form glaciofluvial deposits. A number of landforms can be created; outwash plains spreading out from the glacier front or, closer to the ice front, alluvial fans can be formed. Deposits can form from within the glacier such as eskers. |
Date taken: | Sun Jan 01 00:00:00 GMT 1978 |
Photographer: | Pulsford, J.M. |
Copyright statement: | NERC |
X longitude/easting: | 336050 |
Y latitude/northing: | 203390 |
Coordinate reference system, ESPG code: | 27700 (OSGB 1936 / British National Grid) |
Orientation: | Landscape |
Size: | 376.13 KB; 1000 x 656 pixels; 85 x 56 mm (print at 300 DPI); 265 x 174 mm (screen at 96 DPI); |
Average Rating: | Not yet rated |
Categories: | Unsorted Images |
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