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Uploaded on:
14/02/2009 02:58:22
Digital Asset
File Size:
239.33 KB
1001 x 723 pixels
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P number: P002202
Old photograph number: C01974
Caption: North of Sron Rubha na Gaoithe, south-west of Helmsdale, 0.4 km. south-west of Portgower, Sutherland.
Description: The boulder beds consist of angular blocks and boulders varying in diameter from a few centimetres to the 'fallen stack' which measures 34 m. x 27 m. x 9 m. The origin of the Helmsdale Boulder Bed has been the subject of much speculation. Early suggestions include crush breccias, ice-sheet deposits, violent flood deposits in an estuarine environment, talus from a cliff and the remains of fallen sea stacks. They are now considered to have formed from accumulations of rock-fall breccias at the foot of a submarine escarpment along the line of the Helmsdale Fault. It is thought that the blocks slid relatively slowly down the scarp and mainly along gullies. The interbedded siltstones, mudstones and thin sandstones were probably swept down during storms. The Helmsdale Boulder Bed (Jurassic, Kimmeridgian age) with the famous misnamed gigantic 'fallen stack of Portgower' of Middle Old Red Sandstone age.
Date taken: 01/01/1914
Photographer: Lunn, R.
Copyright statement: Crown
Acknowledgment: This image was digitized with grant-in-aid from SCRAN the Scottish Cultural Resources Access Network
X longitude/easting: 300500
Y latitude/northing: 912500
Coordinate reference system, ESPG code: 27700 (OSGB 1936 / British National Grid)
Orientation: Landscape
Size: 239.33 KB; 1001 x 723 pixels; 85 x 61 mm (print at 300 DPI); 265 x 191 mm (screen at 96 DPI);
Average Rating: Not yet rated
Categories: Unsorted Images, Geoscience subjects/ Stratigraphical  


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