Diagenesis and mineralization processes in Devonian carbonate rocks of the Siding-Gudan lead-zinc mineral subdistrict, Guangxi, Southwest China
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The lead-zinc ore deposits of the Siding-Gudan mineral subdistrict Guangxi are part of the large Nanling district of South China, and hosted in Devonian carbonate rocks. The ore bodies occur significantly along main faults and fault zones, and concentrate up to 300 meters above the Cambrian/Devonian unconformity. Connected with hydrothermal karst, size and volume of the ore bodies increase in proximity to this unconformity.
Moving from the unaffected host rocks to the center of the ore bodies, four zones can be discriminated by the mineral assemblage (pyrite, sphalerite, galena) as well as by the degree of ordering, Ca/Mg, and Fe/Mn ratios of different dolomites. Homogenization temperatures range from 80–100°C (Presqu'ile dolomite) to 230–260°C (massive sphalerite). The sulfides reveal δ34S = −20 to + 8‰, and fluid inclusions display a salinity of 5–12 wt % equivalent NaCl.
The diagenetic and hydrothermal history is similar to that of classic Mississippi Valley Type (MVT) sulfide mineral deposits as, for example, Pine Point in Canada.
Mineralization and remobilization of the sulfides took place during a wide time span from late Paleozoic through Mesozoic. Both processes are considered as an interaction of saline basinal brines ascended from the adjoining dewatering trough, and magmatic-hydrothermal fluids of several magmatic-tectonic events.
KeywordsDolomite Galena Saddle Dolomite Oolitic Shoal Dolomite Type
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- ADAMS, J.E. and RHODES, M.L., 1960, Dolomitization by seepage refluxion:Bull. Amer. Assoc. Petrol. Geol., v. 44, p. 1912–1920.Google Scholar
- ANDERSON, G.M., and MACQUEEN, R. W., 1982, Ore deposit models — 6. Mississippi Valley-type lead-zinc deposits:Geoscience Canada, v. 9, p. 108–117.Google Scholar
- BATHURST, R.G.C., 1975,Carbonate Sediments and Their Diagenesis: Developments in Sedimentology 12, Elsevier, Amsterdam, 685 pp.Google Scholar
- BEALES, F.W. and HARDY, J.L., 1980, Criteria for the recognition of diverse dolomite types with an emphasis on studies on host rocks for Mississippi Valley-type ore deposits,in Zenger, D. H., Dunham, J. B. and Ethington, R.L., eds.,Concepts and models of dolomitization: Soc. Econ. Paleont. Min. Spec. Publ. no. 28, p. 197–213.Google Scholar
- DEFFEYES, K.S., LUCIA, F.J. and WEYL, P.K., 1965, Dolomitization of recent and Plio-Pleistocene sediments by marine evaporite waters on Bonaire, Netherlands Antilles,in Pray, L. C. and Murray, R.C., eds.,Dolomitization and Limestone Diagenesis: Soc. Econ. Paleont. Min. Spec. Publ. 13, p. 71–88.Google Scholar
- DZULYNSKI, S. and SASS-GUSTKIEWICZ, M., 1985, Hydrothermal karst phenomena as a factor in the formation of Mississippi-Valley-type deposits,in Wolf, K.H., ed.,Handbook of Stratabound and Stratiform Ore Deposits, Elsevier, Amsterdam, p. 391–439.Google Scholar
- ELLIS, A.J., 1979, Explored geothermal systems,in Barnes, H.L. ed.,Geochemistry of Hydrothermal Ore Deposits, 2nd Ed.: Wiley, New York, p. 632–683.Google Scholar
- FRITZ, P. and JACKSON, S.A., 1972, Geochemical and isotopic characteristics of Middle Devonian dolomites from Pine Point, northern Canada: 24th Internat. Geol. Congr. Proceed., Section 6, p. 230–243.Google Scholar
- GARRELS, R.M. and CHRIST, C.L., 1965,Solution, Minerals and Equilibria, Harper and Row, New York, 450 pp.Google Scholar
- JACOBSEN, P.L. and USDOWSKI, H.E., Partitioning of strontium between calcite, dolomite, and liquids: An experimental study under high temperature diagenetic condition, and a model for the prediction of mineral pairs for geothermometry:Contrib. Mineral. Petrol., v. 59, p. 171–185.Google Scholar
- KRAUSKOPF, K.B., 1982,Introduction to Geochemistry, 2nd ed., McGraw Hill, London, 617 pp.Google Scholar
- KREBS, W. and MACQUEEN, R.W., 1984, Sequence of diagenetic and mineralization events, Pine Point lead-zinc property, North west Territories, Canada:Bull. Canad. Petrol. Geol. v. 32, p. 434–464.Google Scholar
- KYLE, J.R., 1981, Geology of the Pine Point leadzinc district,in Wolf, K.H., ed.,Handbook of Strata-Bound and Stratiform Ore Deposits, 9:, Elsevier, Amsterdam, p. 643–741.Google Scholar
- RADKE, B.M. and MATHIS, R.L., 1980, On the formation and occurrence of saddle dolomite:Jour. Sed. Petrology, v. 50, p. 1149–1168.Google Scholar
- SANGSTER, D.F., 1976, Carbonate hosted lead-zinc deposits,in Wolf, K.H., ed.,Handbook of Strata-Bound and Stratiform Ore Deposits, 6: Elsevier, Amsterdam, p. 447–456.Google Scholar
- SIBLEY, D.F. and GREGG, J.M., 1987, Classification of dolomite rock textures:Jour. Sed. Petrology, v. 57, no. 6, p. 967–975.Google Scholar
- SKINNER, B.J., 1967, Precipitation of Mississippi Valley-type ores: a possible mechanism. —Econ. Geol. Monogr., 3, p. 363–370.Google Scholar
- WU YI, ZHOU HUAILING, JIANG TINGCAN, FANG DANNIAN and HUANG WUSHENG, 1987, Sedimentary facies, paleogeography and related mineral deposits of Devonian in Guangxi: Explanations to the geological map of Guangxi Province, p. 261–292, Bureau of Geology and Mineral Resources, Nanning, China.Google Scholar
- ZENG YUNFU, SHEN DEQI, ZHANG JINQUAN, CHI SANCHUAN, GE CHACHUA and LIU WENJUN, 1987, Strata-bound ore deposits in the Devonian of Nanling District, South China: Geol. Memoirs Series 4, No. 6, 213 pp. (Geol. Publ. House, Beijing).Google Scholar
- ZHAI YOUHUA, ZHONG KENG and WANG JINBANG, 1985, Classification, geological features and mineralization of Pb−Zn ore deposits in Guangxi, China: Report Bureau of Geology and Mineral Resources of Guangxi, 12 pp., Nanning.Google Scholar
- ZHONG KENG, LI ZHICAI and LI MINGSHENG, 1985, An outline of regional Geology of Guanxi. — Report Bureau of Geology and Mineral Resources of Guangxi, 15 pp., Nanning.Google Scholar