Basin Analysis and Play Characterization

1
Depositional Systems Of Uranium in South
Texas William A. Ambrose October 23, 2007
Bureau of Economic Geology John A. and Katherine
G. Jackson School of Geosciences
Energy Minerals Division American Association
of Petroleum Geologists
2
Acknowledgments
? John Ames
? Jana Robinson
? Joel Lardon
? Lana Dieterich
Publication was authorized by the Director,
Bureau of Economic Geology, The University of
Texas at Austin
3
Outline
? Recent Uranium Production Trends
? Play Elements -Source -Migration -Mineralizat
ion -Seal
? Catahoula Formation
? Oakville Sandstone
? Summary
4
Estimates of 21st century World energy
supplies Billion barrels oil equivalent
Billion barrels oil equivalent yr-1
2100
1900
2000
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U. S. Uranium Deposits
U3O8 reserves, 85.00/lb. Wyoming
301 New Mexico 289 AZ, CO, UT
128 Texas 17
Source Uranium Industry Annual 2002
www.stockinterview.com
million pounds Source EIA (2006)
Spot Price, Sept. 24, 2007 85.00/lb. (Ux
Consulting Company, LLC)
Yellowcake
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U. S. Uranium Production
EIA (2007)
QAd6136
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South Texas Uranium Trends
40 mi
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GOM Tertiary Uranium-Bearing Units
9
Outline
? Recent Uranium Production Trends
? Play Elements -Source -Migration -Mineralizat
ion -Seal
? Catahoula Formation
? Oakville Sandstone
? Summary
10
Oligocene Volcanic Source
Modified from Galloway (1977)
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Migration
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Mineralization Roll Front Genesis
B
A
Modified from Hobday and Galloway (1999)
QAd6142
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Seals and Semi-Confined Aquifers
Floodplain shales and flooding surfaces
Serve to concentrate groundwater flow
in transmissive intervals
Promote effective recharge and discharge of
meteoric water
Leaky seals along fault promote upward migration
of reducing fluids
Simulated Fault
Modified from Henry et al. (1982)
14
Outline
? Recent Uranium Production Trends
? Play Elements -Source -Migration -Mineralizat
ion -Seal
? Catahoula Formation
? Oakville Sandstone
? Summary
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Catahoula Paleogeography
Modified from Galloway (1977)
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Catahoula Net Sandstone South Texas
Modified from Galloway (1977)
Holiday- El Mesquite
Bruni
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Catahoula Sandstone Geometry Northeastern Duval
County
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Bruni and Holiday-El Mesquite
600,000 lb. resources 0.070 grade (EIA, 2002)
B
Bruni
B
Holiday- El Mesquite
5 mi
Modified from Galloway and Kaiser (1980)
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Bruni Roll Front
Contours Weight-percent Iron Sulfide
B
B
Southeast
Northwest
U-rich Oxidizing groundwater
Dom. Pyrite
Dom. Marcasite
Limonite
Modified from Goldhaber and Reynolds (1977)
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Outline
? Recent Uranium Production Trends
? Play Elements -Source -Migration -Mineralizat
ion -Seal
? Catahoula Formation
? Oakville Sandstone
? Summary
21
Oakville Fluvial Depocenters South Texas
Modified from Galloway et al. (1982)
George West
Ray Point
Rosita
Vasquez
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George West Uranium Mineralization
Modified from Galloway et al. (1982)
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Summary Uranium Play Elements in South Texas
Adequacy and Controls
Play Element