Economic Geology Volume 2

Economic Geology Volume 2

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1907 edition. Excerpt: ...then shown that the so-called saddle reef of Broken Hill is in the lamination of a metamorphic igneous rock and not in the more regular anticlinal folds of a series of contorted sediments. The. inference is drawn that there is no necessary superposition of saddle reefs at Broken Hill as the lamina of metamorphic rocks or foliated igneous rocks cannot be relied upon to 1 Oral communication. produce superposed anticlines and the occurrence of one saddle above by no means indicates the presence of others below. The latter part of the paper contains a brief discussion of the indicators of Ballarat and corrects an erroneous impression which has found its way into the literature of the subject. It is of sufficient importance to warrant a quotation in full. "The early miners of Ballarat were faced by the paradox of finding gold in large nuggets and coarse grains in the gravels, and yet the adjacent hills, though the rocks were exceptionally well shown, contained no quartz veins comparable in size to the nuggets shed from them. Hence arose the belief that the nuggets grew by slow accretion in the gravels from percolating gold solutions. This theory has been now almost universally abandoned; but it is of historic interest as indicating the difficulty of believing, that the nuggets could have been derived from the small, irregular quartz veins, that seam the hills of Ballarat East. "The nuggets found in the surface gravels and soils of Ballarat have been found along a line running north and south through the town and suburbs of Ballarat East. The nuggets were no doubt formed in small quartz veins, where they are cut across by narrow seams called indicators. These indicators have been generally regarded as originally layers of sediment especially...show more

Product details

  • Paperback | 278 pages
  • 189 x 246 x 15mm | 499g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236652711
  • 9781236652713