Geological Survey Professional Paper Volume 313

Geological Survey Professional Paper Volume 313

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This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1987* edition. Excerpt: ... by a small anticline regarded by Pardee (1936) as a west branch of the Princeton anticline. Between Gird and Douglas Creeks are two fault blocks that have been variously interpreted as downfolded or down-faulted segments of the Philipsburg thrust, but from the data presented on published maps, it appears likely that they are fault slices resulting from imbrication of the Georgetown (?) thrust. The Retort Member was not measured or sampled within the Gird Creek syncline, but at the nearby East Edgar adit (lot 1389), which is on the east limb of the Princeton anticline a few hundred feet south of the northernmost exposure of Permian rocks, the member is nearly 14 feet thick and is estimated to contain an average of 23 percent P20s (pl. 33). It includes 7.5 feet of rock containing 29.5 percent P205, 4 feet of which contains 33.6 percent P2Or, . At its base is a bed of phosphatic conglomerate 0.6 foot thick, but its most striking feature at this locality is a 3.4-foot bed, at its top, of sandy phosphorite containing 24.4 percent P205. This represents the upper sandy zone (see pl. 32), which is elsewhere much thinner and less phosphatic. The rocks at this locality are rather light colored and appear to be considerably weathered, so the proportion of phosphate probably decreases downward. At the West Edgar mine, which is on the east edge of the Gird Creek syncline block, the phosphate beds are steeply dipping to overturned and are reached by a crosscut from the west; the mine produced little phosphate. The shallow workings were too much caved to be explored; but it was noted that some of the strata were considerably sheared. DOUGLAS CREEK SYNCLINE The Douglas Creek syncline, between the Princeton and Douglas Mountain anticlines, is more

Product details

  • Paperback | 42 pages
  • 189 x 246 x 2mm | 95g
  • United States
  • English
  • black & white illustrations
  • 1236961218
  • 9781236961211