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Title: Chemical and isotopic studies of granitic Archean rocks, Owl Creek Mountains, Wyoming: Uranium-thorium-lead systematics of an Archean granite from the Owl Creek Mountains, Wyoming

Abstract

Isotopic analyses of apparently unaltered whole-rock samples of a granite from the Owl Creek Mountains, Wyo., yield a lead-lead isochron age of 2730 {plus minus} 35 Ma, which is somewhat older than the age obtained by the rubidium-strontium whole-rock method. Thorium-lead data for the same samples deviate markedly from an isochronal relation; however, calculated initial {sup 208}Pb/{sup 204}Pb ratios correlate with whole-rock {delta}{sup 18}O values and lead to the conclusion that the {sup 232}Th-{sup 208}Pb data are not colinear because of an originally heterogeneous granitic magma. Relationships in the {sup 207}Pb/{sup 235}U-{sup 206}Pb/{sup 238}U system show that uranium was mobilized during early Laramide time or shortly before, such that most surface and shallow drill-core samples lost 60-80 percent of their uranium, and some fractured, deeper drill-core samples gained from 50 to 10,000 percent uranium. Fission-track maps show that much uranium is located along edges and cleavages of biotite and magnetic where it is readily accessible to oxidizing ground water. Furthermore, qualitative comparisons of uranium distribution in samples with excess radiogenic lead and in samples with approximately equilibrium amounts of uranium and lead suggest that the latter contain more uranium in these readily accessible sites. Unlike other granites that have uraniummore » distributions and isotopic systematics similar to those observed in this study, the granite of the Owl Creek Mountains is not associated with economic uranium deposits.« less

Authors:
; ;
Publication Date:
OSTI Identifier:
6978125
Resource Type:
Journal Article
Journal Name:
United States Geological Survey, Professional Paper; (USA)
Additional Journal Information:
Journal Name: United States Geological Survey, Professional Paper; (USA)
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; GRANITES; AGE ESTIMATION; WYOMING; BIOTITE; DRILL CORES; FISSION TRACKS; GEOLOGIC HISTORY; GROUND WATER; ISOTOPE DATING; ISOTOPE RATIO; LEAD 204; LEAD 206; LEAD 208; LEAD ORES; MAGNETITE; OXYGEN 18; THORIUM 232; THORIUM ORES; URANIUM 235; URANIUM 238; URANIUM ORES; ACTINIDE ISOTOPES; ACTINIDE NUCLEI; ALPHA DECAY RADIOISOTOPES; CHALCOGENIDES; EVEN-EVEN NUCLEI; EVEN-ODD NUCLEI; FEDERAL REGION VIII; HEAVY NUCLEI; HOURS LIVING RADIOISOTOPES; HYDROGEN COMPOUNDS; IGNEOUS ROCKS; IRON COMPOUNDS; IRON ORES; IRON OXIDES; ISOMERIC TRANSITION ISOTOPES; ISOTOPES; LEAD ISOTOPES; LIGHT NUCLEI; MICA; MINERALS; MINUTES LIVING RADIOISOTOPES; NORTH AMERICA; NUCLEI; ORES; OXIDE MINERALS; OXIDES; OXYGEN COMPOUNDS; OXYGEN ISOTOPES; PARTICLE TRACKS; PLUTONIC ROCKS; RADIOISOTOPES; ROCKS; SILICATE MINERALS; STABLE ISOTOPES; THORIUM ISOTOPES; TRANSITION ELEMENT COMPOUNDS; URANIUM ISOTOPES; USA; WATER; YEARS LIVING RADIOISOTOPES; 050100* - Nuclear Fuels- Reserves, Exploration, & Mining

Citation Formats

Stuckless, J S, Nkomo, I T, and Butt, K A. Chemical and isotopic studies of granitic Archean rocks, Owl Creek Mountains, Wyoming: Uranium-thorium-lead systematics of an Archean granite from the Owl Creek Mountains, Wyoming. United States: N. p., 1986. Web.
Stuckless, J S, Nkomo, I T, & Butt, K A. Chemical and isotopic studies of granitic Archean rocks, Owl Creek Mountains, Wyoming: Uranium-thorium-lead systematics of an Archean granite from the Owl Creek Mountains, Wyoming. United States.
Stuckless, J S, Nkomo, I T, and Butt, K A. 1986. "Chemical and isotopic studies of granitic Archean rocks, Owl Creek Mountains, Wyoming: Uranium-thorium-lead systematics of an Archean granite from the Owl Creek Mountains, Wyoming". United States.
@article{osti_6978125,
title = {Chemical and isotopic studies of granitic Archean rocks, Owl Creek Mountains, Wyoming: Uranium-thorium-lead systematics of an Archean granite from the Owl Creek Mountains, Wyoming},
author = {Stuckless, J S and Nkomo, I T and Butt, K A},
abstractNote = {Isotopic analyses of apparently unaltered whole-rock samples of a granite from the Owl Creek Mountains, Wyo., yield a lead-lead isochron age of 2730 {plus minus} 35 Ma, which is somewhat older than the age obtained by the rubidium-strontium whole-rock method. Thorium-lead data for the same samples deviate markedly from an isochronal relation; however, calculated initial {sup 208}Pb/{sup 204}Pb ratios correlate with whole-rock {delta}{sup 18}O values and lead to the conclusion that the {sup 232}Th-{sup 208}Pb data are not colinear because of an originally heterogeneous granitic magma. Relationships in the {sup 207}Pb/{sup 235}U-{sup 206}Pb/{sup 238}U system show that uranium was mobilized during early Laramide time or shortly before, such that most surface and shallow drill-core samples lost 60-80 percent of their uranium, and some fractured, deeper drill-core samples gained from 50 to 10,000 percent uranium. Fission-track maps show that much uranium is located along edges and cleavages of biotite and magnetic where it is readily accessible to oxidizing ground water. Furthermore, qualitative comparisons of uranium distribution in samples with excess radiogenic lead and in samples with approximately equilibrium amounts of uranium and lead suggest that the latter contain more uranium in these readily accessible sites. Unlike other granites that have uranium distributions and isotopic systematics similar to those observed in this study, the granite of the Owl Creek Mountains is not associated with economic uranium deposits.},
doi = {},
url = {https://www.osti.gov/biblio/6978125}, journal = {United States Geological Survey, Professional Paper; (USA)},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 01 00:00:00 EST 1986},
month = {Wed Jan 01 00:00:00 EST 1986}
}