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Uploaded on:
17/02/2009 08:29:50
Type:
Digital Asset
File Size:
328.83 KB
Dimensions:
1001 x 708 pixels
3463 views 6 downloads
P number: P200018
Old photograph number: A00020
Caption: Granite quarry, 1/4 m. north of Longdowns, Mabe, Cornwall. Looking north-east.
Description: There were many quarries working the Carnmenellis or Dartmoor Granite with the principal ones confined to the eastern part of the massif where the granite has fewer structural defects. Until about 1800 granite for building was taken from the vast amounts of surface debris. Longdowns granite quarry shows the characteristic jointing seen in the Carnmenellis Granite. The joint patterns in granites play an important part in the quarrying process, determining the size of block that can be produced and the direction in which the rock face should be worked. The six principal granite bosses of the south-west peninsula have all been extensively worked in the past for building purposes. The granites were all intruded during the late Carboniferous Variscan orogeny. Many famous quarry names are associated with the granite industry of the area - De Lank, Cheesewring, Penryn, Haytor and Lamorna.
Date taken: 01/08/1904
Photographer: Hall, T.C.
Copyright statement: Crown
X longitude/easting: 175500
Y latitude/northing: 34500
Coordinate reference system, ESPG code: 27700 (OSGB 1936 / British National Grid)
Orientation: Landscape
Size: 328.83 KB; 1001 x 708 pixels; 85 x 60 mm (print at 300 DPI); 265 x 187 mm (screen at 96 DPI);
Average Rating: Not yet rated
Categories: Unsorted Images, Geoscience subjects/ Economic geology/ Building stones, granite, Geoscience subjects/ Structural features/ Jointing, in igneous rocks  

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