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Title: Potential precious and strategic metals as by-products of uranium mineralized breccia pipes in northern Arizona

Conference · · Am. Assoc. Pet. Geol., Bull.; (United States)
OSTI ID:5502101

The development of caves within the Mississippian Redwall Limestone, accompanied by later upward stoping of overlying Paleozoic and Triassic rock, resulted in the formation of breccia pipes. Despite the depressed uranium market, some of these pipes are presently being mined for uranium. No brecciated rock within pipes has been observed above its normal stratigraphic position, nor is any volcanic rock associated in space or time with these pipes. Mineralized rock transects any strata from the Redwall Limestone to the Triassic Chinle Formation. Over 400 collapse structures, believed to represent breccia pipes (many with exposed breccia), have been mapped. Those with gamma radiation exceeding 2.5 times background (57 pipes) have been sampled (155 samples). Of these oxidized surface samples collected solely on the basis of radioactivity, 30% have Ag exceeding 10 ppm, some with up to 1150 ppm. Two samples of brecciated, oxidized sandstone with radioactivity exceeding 20 and 40 times background from this adit, and another sample of hematite-, malachite-, and chalcocite-impregnated sandstone from a higher level adit contained high concentrations of Au, Hg, Cd, and W, along with many elements commonly anomalous in mineralized breccia pipes from northern Arizona: Ag, As, Co, Cu, Mo, Ni, and Pb. The potential for economic recovery from breccia pipes of elements other than U, such as Ag, Au, Co, and Ni, should not be ignored as their concentrations are even more enhanced in unoxidized samples.

Research Organization:
Geological Survey, Denver, CO
OSTI ID:
5502101
Report Number(s):
CONF-8408161-; TRN: 85-018739
Journal Information:
Am. Assoc. Pet. Geol., Bull.; (United States), Vol. 68:7; Conference: Energy and More in '84, Salt Lake City, UT, USA, 27 Aug 1984
Country of Publication:
United States
Language:
English