CHEN Fei. Characteristics of Grain Size of Delta Sandbody Framework in Yanchang Formation Upper Triassic,North Shaanxi[J]. Acta Sedimentologica Sinica, 2010, 28(1): 58-67.
Citation:
Min Maozhong, Wang Xiangyun, Shen Baopei, Wen Guangdou, Fan Tao. Isotopic Geochemistry of Metallogeny for the Largest Paleokarst Uranium Deposit in China[J]. Acta Sedimentologica Sinica, 1997, 15(1): 118-122.
Isotopic Geochemistry of Metallogeny for the Largest Paleokarst Uranium Deposit in China
1 Department of Earth Sciences Nanjing University Nanjing 210008;
2 No.303 Geological Party Bureau of Geology and Lxploration of Central-Ruth China Hunan 425808
Received Date: 1995-03-29
Publish Date:
1997-03-10
Abstract
A uranium deposit is the largest paleokarst type U deposit in loth scale and tonnage in China. Thedeposit is formed below a fossil cave and in a faulting}olution breccia system in the Lower Carbonifer-ous limestone. The temperature of mineralizing fluids ranges from 1810℃to 1500 ℃Four U一Pb ages forpitchblende and whole rock ores, 135, 131, 119 and 65 Ma, have been determined, which are obviouslyyounger than those of the wall rocks. Sulfur isotope data show that the δ34 S values of pyrites from theores range from 1.00 ‰to一15. 3‰with a mean value of一6.87‰,closel to those of pyrites fromthe wall rocks(1. 00‰一15.60‰，mean- 7.06‰)，suggesting that the wall rocks are the source ofsulfur for mineralization. The five analyzed samples of calcites from the ores have δ13 Cvalues between 0.34‰and-3.19‰(mean一1.50‰).The similarity between the average carbon isotope composition of the ores(一1.50‰)and the wall rocks(0.53‰)is interpreted to result from an isotope exchange between the wall rock and mineralizing fluid. The lead isotope composition of pyrites from the ores andwhole}ock of Lower Carboiferous sugggests that the source of lead and urarnum in the deposit is vari-ous in strata of the ore field.The value of δ18O and δD for mineralizing fluids range from 1.5‰o 7.3‰ and from一30.4‰to一84.9‰,of metamorphic and meteoric waters.respectively, indicating that the mineralizing fluid is a mixed waterThe mineralizing process is clowly related to development historyof regional tectordic movemnets and multi-episode paleokarstification. Thus, it is named as hydrothermalreworked paleokarst type uranium deposit.
2 Shelton K L and Rye D M. Sulfur isotope compositions ofores from mines Cape, Quebec; an example of sulfate-sulfi deisotopic disequilibria in ore-forming fluids with applications to other porphyry-type deposits, Economic Geology, 198 77 1688-1709.
4 Sheppard S M F. Charackerization and isotopic variations in Ylatnral watersRev Mineralogy, 1986, 16 165- 183
5 ELSharkawi W A.ELArefM M and Motelib A AManganese deposits in a Carboniferous paleokarst profile, Um Bogma Region,West-central Sinal.Egypt, Mineralum De- posita, 1990, 25 34-43.
6 Olson RA. Genesis of paleoka rst and s t rat a-b ou nd zinc-leadsulfide deposits in a Proterozoic dolostonet NorthernIsland, Canada, Economic Geology, 1984, 79 1056-1103
7 W allace A R.The relief canyon gold deposit, Nevadaa mineralized solution breccia Economic Geology, 1989, 84 274-190
Abstract: A uranium deposit is the largest paleokarst type U deposit in loth scale and tonnage in China. Thedeposit is formed below a fossil cave and in a faulting}olution breccia system in the Lower Carbonifer-ous limestone. The temperature of mineralizing fluids ranges from 1810℃to 1500 ℃Four U一Pb ages forpitchblende and whole rock ores, 135, 131, 119 and 65 Ma, have been determined, which are obviouslyyounger than those of the wall rocks. Sulfur isotope data show that the δ34 S values of pyrites from theores range from 1.00 ‰to一15. 3‰with a mean value of一6.87‰,closel to those of pyrites fromthe wall rocks(1. 00‰一15.60‰，mean- 7.06‰)，suggesting that the wall rocks are the source ofsulfur for mineralization. The five analyzed samples of calcites from the ores have δ13 Cvalues between 0.34‰and-3.19‰(mean一1.50‰).The similarity between the average carbon isotope composition of the ores(一1.50‰)and the wall rocks(0.53‰)is interpreted to result from an isotope exchange between the wall rock and mineralizing fluid. The lead isotope composition of pyrites from the ores andwhole}ock of Lower Carboiferous sugggests that the source of lead and urarnum in the deposit is vari-ous in strata of the ore field.The value of δ18O and δD for mineralizing fluids range from 1.5‰o 7.3‰ and from一30.4‰to一84.9‰,of metamorphic and meteoric waters.respectively, indicating that the mineralizing fluid is a mixed waterThe mineralizing process is clowly related to development historyof regional tectordic movemnets and multi-episode paleokarstification. Thus, it is named as hydrothermalreworked paleokarst type uranium deposit.
CHEN Fei. Characteristics of Grain Size of Delta Sandbody Framework in Yanchang Formation Upper Triassic,North Shaanxi[J]. Acta Sedimentologica Sinica, 2010, 28(1): 58-67.
Citation:
Min Maozhong, Wang Xiangyun, Shen Baopei, Wen Guangdou, Fan Tao. Isotopic Geochemistry of Metallogeny for the Largest Paleokarst Uranium Deposit in China[J]. Acta Sedimentologica Sinica, 1997, 15(1): 118-122.
2 Shelton K L and Rye D M. Sulfur isotope compositions ofores from mines Cape, Quebec; an example of sulfate-sulfi deisotopic disequilibria in ore-forming fluids with applications to other porphyry-type deposits, Economic Geology, 198 77 1688-1709.
4 Sheppard S M F. Charackerization and isotopic variations in Ylatnral watersRev Mineralogy, 1986, 16 165- 183
5 ELSharkawi W A.ELArefM M and Motelib A AManganese deposits in a Carboniferous paleokarst profile, Um Bogma Region,West-central Sinal.Egypt, Mineralum De- posita, 1990, 25 34-43.
6 Olson RA. Genesis of paleoka rst and s t rat a-b ou nd zinc-leadsulfide deposits in a Proterozoic dolostonet NorthernIsland, Canada, Economic Geology, 1984, 79 1056-1103
7 W allace A R.The relief canyon gold deposit, Nevadaa mineralized solution breccia Economic Geology, 1989, 84 274-190
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CHEN Fei. Characteristics of Grain Size of Delta Sandbody Framework in Yanchang Formation Upper Triassic,North Shaanxi[J]. Acta Sedimentologica Sinica, 2010, 28(1): 58-67.
CHEN Fei. Characteristics of Grain Size of Delta Sandbody Framework in Yanchang Formation Upper Triassic,North Shaanxi[J]. Acta Sedimentologica Sinica, 2010, 28(1): 58-67.
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