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Title: Paragenesis and conditions of formation of ore minerals from metalliferous breccia pipes, N. Arizona

Abstract

Ore deposits within N. Arizona breccia pipes are currently being exploited for U, but at various times during the past century Cu, Pb, Zn, and Ag were mined. These pipes formed as solution-collapses within the Mississippian Redwall Ls and stopped upward through overlying strata. The principal ore minerals are: uraninite, chalcopyrite, chalcocite, tennantite-tetrahedrite, galena, sphalerite, millerite, gersdorffite, siegenite, and molybdenite. Common gangue minerals are marcasite, pyrite, barite, dolomite, calcite and quartz. Marcasite and pyrite appear to have formed prior to the ore minerals, followed closely by chalcopyrite. The Ni and Co phases also appear to be early: gersdorffite crystals are rimmed by later galena. Tennantite-tetrahedrite formed later than both galena and sphalerite; uraninite, the latest ore mineral, consisting fills interstices. Primary fluid inclusions in dolomite, quartz, and sphalerite show filling temperatures from 80 to 145/degree/C and high salinities, averaging 15 wt% NaCl (eq). Secondary inclusions in sphalerite have consistently higher filling temperatures from 105 to 173/degree/C, but similar salinities. Rock-Eval pyrolysis of pyrobitumen yields little or no volatile hydrocarbons (S/sub 1/=0-0.2 mg/gm), but large amounts of pyrolytic hydrocarbons (S/sub 2/=105-216 mg/gm). Temperatures of maximum pyrolytic yield are relatively low (424-430/degree/C), suggesting temperatures did not exceed 150/degree/C following pyrobitumen emplacement. Exceptmore » for uraninite, the breccia pipes are similar to Mississippi Valley-type (MVT) deposits in mineralogy, fluid-inclusion filling temperatures and salinities, and associated organic material. Because MVT deposits do not host U minerals, a possible two-stage mineralization history of the pipes is suggested, the first by a MVT brine and perhaps a second forming the uraninite.« less

Authors:
;
Publication Date:
Research Org.:
Geological Survey, Denver, CO (USA)
OSTI Identifier:
6005226
Report Number(s):
CONF-8510489-
Journal ID: CODEN: GAAPB
Resource Type:
Conference
Journal Name:
Geol. Soc. Am., Abstr. Programs; (United States)
Additional Journal Information:
Journal Volume: 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28-31 Oct 1985
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 58 GEOSCIENCES; ARIZONA; URANIUM ORES; MINERALIZATION; MINERALOGY; BARITE; BRINES; CHALCOPYRITE; DOLOMITE; GALENA; GEOLOGIC HISTORY; GEOTHERMOMETRY; HYDROCARBONS; INCLUSIONS; LIMESTONE; MISSISSIPPIAN PERIOD; PARAGENESIS; PYRITE; QUARTZ; SPHALERITE; URANINITES; ALKALINE EARTH METAL COMPOUNDS; BARIUM COMPOUNDS; BARIUM SULFATES; CALCIUM CARBONATES; CALCIUM COMPOUNDS; CARBON COMPOUNDS; CARBONATE MINERALS; CARBONATE ROCKS; CARBONATES; CHALCOGENIDES; COPPER COMPOUNDS; COPPER SULFIDES; FEDERAL REGION IX; GEOLOGIC AGES; IRON COMPOUNDS; IRON SULFIDES; LEAD COMPOUNDS; LEAD SULFIDES; MAGNESIUM CARBONATES; MAGNESIUM COMPOUNDS; MATERIALS; MINERALS; NORTH AMERICA; ORES; ORGANIC COMPOUNDS; OXIDE MINERALS; OXIDES; OXYGEN COMPOUNDS; PALEOZOIC ERA; RADIOACTIVE MATERIALS; RADIOACTIVE MINERALS; ROCKS; SEDIMENTARY ROCKS; SILICON COMPOUNDS; SILICON OXIDES; SULFATE MINERALS; SULFATES; SULFIDE MINERALS; SULFIDES; SULFUR COMPOUNDS; TRANSITION ELEMENT COMPOUNDS; URANIUM MINERALS; USA; 050100* - Nuclear Fuels- Reserves, Exploration, & Mining; 580300 - Mineralogy, Petrology, & Rock Mechanics- (-1989)

Citation Formats

Wenrich, K J, and Pratt, L M. Paragenesis and conditions of formation of ore minerals from metalliferous breccia pipes, N. Arizona. United States: N. p., 1985. Web.
Wenrich, K J, & Pratt, L M. Paragenesis and conditions of formation of ore minerals from metalliferous breccia pipes, N. Arizona. United States.
Wenrich, K J, and Pratt, L M. 1985. "Paragenesis and conditions of formation of ore minerals from metalliferous breccia pipes, N. Arizona". United States.
@article{osti_6005226,
title = {Paragenesis and conditions of formation of ore minerals from metalliferous breccia pipes, N. Arizona},
author = {Wenrich, K J and Pratt, L M},
abstractNote = {Ore deposits within N. Arizona breccia pipes are currently being exploited for U, but at various times during the past century Cu, Pb, Zn, and Ag were mined. These pipes formed as solution-collapses within the Mississippian Redwall Ls and stopped upward through overlying strata. The principal ore minerals are: uraninite, chalcopyrite, chalcocite, tennantite-tetrahedrite, galena, sphalerite, millerite, gersdorffite, siegenite, and molybdenite. Common gangue minerals are marcasite, pyrite, barite, dolomite, calcite and quartz. Marcasite and pyrite appear to have formed prior to the ore minerals, followed closely by chalcopyrite. The Ni and Co phases also appear to be early: gersdorffite crystals are rimmed by later galena. Tennantite-tetrahedrite formed later than both galena and sphalerite; uraninite, the latest ore mineral, consisting fills interstices. Primary fluid inclusions in dolomite, quartz, and sphalerite show filling temperatures from 80 to 145/degree/C and high salinities, averaging 15 wt% NaCl (eq). Secondary inclusions in sphalerite have consistently higher filling temperatures from 105 to 173/degree/C, but similar salinities. Rock-Eval pyrolysis of pyrobitumen yields little or no volatile hydrocarbons (S/sub 1/=0-0.2 mg/gm), but large amounts of pyrolytic hydrocarbons (S/sub 2/=105-216 mg/gm). Temperatures of maximum pyrolytic yield are relatively low (424-430/degree/C), suggesting temperatures did not exceed 150/degree/C following pyrobitumen emplacement. Except for uraninite, the breccia pipes are similar to Mississippi Valley-type (MVT) deposits in mineralogy, fluid-inclusion filling temperatures and salinities, and associated organic material. Because MVT deposits do not host U minerals, a possible two-stage mineralization history of the pipes is suggested, the first by a MVT brine and perhaps a second forming the uraninite.},
doi = {},
url = {https://www.osti.gov/biblio/6005226}, journal = {Geol. Soc. Am., Abstr. Programs; (United States)},
number = ,
volume = 17,
place = {United States},
year = {Tue Jan 01 00:00:00 EST 1985},
month = {Tue Jan 01 00:00:00 EST 1985}
}

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