Ore mineral characteristics and zircon U-Pb geochronology of Yuanjiacun iron deposit in Shanxi
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摘要
In order to further understand the ore characteristics and metallogenic age of Yuanjiacun iron deposit in Shanxi, the mineral composition characteristics of iron ore were studied on the basis of field investigation and microscopic observation. Magnetite, hematite, goethite and pyrite of different stages were identified according to their texture and structure features. Two sets of ~(207)Pb/~(206)Pb ages have been obtained by ICPMS isotope dating of magnetite quartzite, of which the zircon age with metamorphic origin is 1 916±88 Ma, representing the main metamorphic age of iron deposit. Another group of magmatic zircons with rhythmic zones are of 2 280±30 Ma age, representing the diagenetic age of iron formation. In addition, scattered age records after metamorphism indicate frequent hydrothermal events after mineralization. Based on the mineral fabric characteristics and the age data of zircons of different origins, it is known that the deposit has undergone sedimentary mineralization period, metamorphic mineralization period, hydrothermal mineralization period and weathering mineralization period.
In order to further understand the ore characteristics and metallogenic age of Yuanjiacun iron deposit in Shanxi, the mineral composition characteristics of iron ore were studied on the basis of field investigation and microscopic observation. Magnetite, hematite, goethite and pyrite of different stages were identified according to their texture and structure features. Two sets of ~(207)Pb/~(206)Pb ages have been obtained by ICPMS isotope dating of magnetite quartzite, of which the zircon age with metamorphic origin is 1 916±88 Ma, representing the main metamorphic age of iron deposit. Another group of magmatic zircons with rhythmic zones are of 2 280±30 Ma age, representing the diagenetic age of iron formation. In addition, scattered age records after metamorphism indicate frequent hydrothermal events after mineralization. Based on the mineral fabric characteristics and the age data of zircons of different origins, it is known that the deposit has undergone sedimentary mineralization period, metamorphic mineralization period, hydrothermal mineralization period and weathering mineralization period.
In order to further understand the ore characteristics and metallogenic age of Yuanjiacun iron deposit in Shanxi, the mineral composition characteristics of iron ore were studied on the basis of field investigation and microscopic observation. Magnetite, hematite, goethite and pyrite of different stages were identified according to their texture and structure features. Two sets of ~(207)Pb/~(206)Pb ages have been obtained by ICPMS isotope dating of magnetite quartzite, of which the zircon age with metamorphic origin is 1 916±88 Ma, representing the main metamorphic age of iron deposit. Another group of magmatic zircons with rhythmic zones are of 2 280±30 Ma age, representing the diagenetic age of iron formation. In addition, scattered age records after metamorphism indicate frequent hydrothermal events after mineralization. Based on the mineral fabric characteristics and the age data of zircons of different origins, it is known that the deposit has undergone sedimentary mineralization period, metamorphic mineralization period, hydrothermal mineralization period and weathering mineralization period.
引文
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Dai Y P, Zhang L C, Zhu M T, et al. 2013. Chentaigou BIF-type iron deposit, Anshan area associated with Archean crustal growth: constraints from zircon U-Pb dating and Hf isotope. Acta Petrologica Sinica, 29(7): 2537-2550. (in Chinese with English abstract)
Geng Y S, Wan Y S, Shen Q H, et al. 2000. Chronological framework for early Precambrian major geological events in Lüliang area. Acta Geologica Sinica, (3):216-223. (in Chinese)
Geng Y S, Wan Y S, Yang C H. 2003. The Palaeoproterozoic rift-type volcanism in Lüliangshan area, Shanxi Province, and its geological significance. Acta Geoscientica Sinica, (2): 97-104. (in Chinese with English abstract)
Geng Y S, Wan Y S, Yang C H. 2008. A comprehensive study report on Paleoproterozoic system in China-determination of major Paleoproterozoic geological events in Lüliang area and preliminary discrimination of paleoproterozoic. Beijing: Geological Publishing House, 515-533. (in Chinese)
Glasby G P, Schulz H D. 1999. Eh, pH diagrams for Mn, Fe, Co, Ni, Cu and as under seawater conditions: application of two new types of the Eh, pH diagrams to the study of specific problems in marine geochemistry. Aquatic Geochemistry, 5(3): 227-248.
Gross G A. 1991. Genetic concepts for iron-formation and associated metalliferous sediments. Economic Geology Monograph, (8): 51-81.
Han T M. 1988. Origin of magnetite in Precambrian iron-formations of low metamorphic grade//IAGOD Quadrennial Symposium, 7th, Proceedings, 641-656.
He H. 2013. Discussion on formation conditions of sedimentary metamorphic iron deposit in Yuanjiacun, Lan County, Shanxi Province. Huabei Land and Resources, (3): 89-91. (in Chinese)
Jackson S E, Pearson N J, Griffin W L, et al. 2004. The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U-Pb zircon geochronology. Chemical Geology, 211(1): 47-69.
James H L. 1954. Sedimentary facies of iron-formation. Economic Geology, 49(3): 235-293.
Liu M J. 2013. Hydrothermal metasomatism and its metallogenic significance of the Gongchangling iron deposit, Liaoning: master's degree thesis. Beijing: China University of Geosciences. (in Chinese with English abstract)
Liu T B, Zhao Y R. 2004. Metallogenesis of the Lüliang terrane and the Wutai terrane. Journal of Taiyuan University of Technology, (5): 618-621. (in Chinese)
Ludwig K R. 2001. User's manual for Isoplot /Ex Rev. 2.4. Berkeley: Berkeley Geochronology Center Special Publication, 56.
Regional Geological Survey Team of Shanxi Provincial of Geology and Mineral Resources (RGST). 1975. Summary of regional mineral resources in Shanxi Province. Yuci: RGST.
Schwertmann U, Murad E.1983. Effect of pH on the formation of goethite and hematite from ferrihydrite. Clays and Clay Minerals, 31(4): 277-284
Shen B F, Song L S, Li Z H. 1982. Analysis of sedimentary facies and formation conditions of Yuanjiacun iron construction in Lan County, Shanxi. Journal of Changchun University of Earth Sciences, (S1): 31-51,166. (in Chinese)
Shen Q H. 1998. Geological characteristics and formation background of Early Precambrian banded ferric rocks in North China Platform. Beijing: Geological Publishing House, 1-30. (in Chinese)
Song B, Zhang Y H, Wan Y S, et al. 2002. Zircon SHRIMP sample target production, age determination and discussion of related phenomena. Geological Review, 48(S1): 26-30. (in Chinese)
Taylor D, Delstra H J, Harding A E, et al. 2001. Genesis of high-grade hematite orebodies of the Hamersley Province, Western Australia. Economic Geology, 96: 837-873.
Trendall A F, Morris R C. 1983.Iron-formation, facts and problems. Amsterdam: Elsevier, 1-11.
Wang C L, Zhang L C, Lan C Y, et al. 2012. Geochemical characteristics and genesis of Yuanjiacun iron ore in Lüliang, Shanxi. Mineral Deposits, 31(S1): 129-130. (in Chinese)
Wang C L, Zhang L C, Lan C Y, et al. 2014. BIF REE geochemistry of the Paleoproterozoic Yuanjiacun iron deposit in Lüliang, Shanxi and its indication for major oxidation events. Science China Earth Sciences, 44(11): 2389-2405.
Wang C L, Zhang L C, Lan C Y, et al. 2015. Analysis of sedimentary facies and depositional environment of the Yuanjiacun banded iron formation in the Lüliang area, Shanxi Province. Acta Petrologica Sinica, 31(6): 1671-1693. (in Chinese with English abstract)
Wang X M, Yang K G, Sun S F, et al. 2011. The structure and composition of ferrihydrite and its environmental geo-chemical behaviors. Earth Science Frontiers, 18(2): 339-347. (in Chinese with English abstract)
Xu C L, Zhu G X, Tan Y L, et al. 2008. Division of Precambrian strata in Lüliang mountainous area. Geological Review, (4): 459-465.
Yu J H, Wang D Z, Wang C Y, et al. 1997. Zircon U-Pb age of Shanxi Lüliang group and its main metamorphism. Geological Review, (4): 403-408. (in Chinese)
Zhu J C, Zhang F S. 1987. Forming conditions of Precambrian iron deposit in Yuanjiacun mining area, Shanxi. Mineral Deposits, (1): 11-21. (in Chinese)
Dai Y P, Zhang L C, Zhu M T, et al. 2013. Chentaigou BIF-type iron deposit, Anshan area associated with Archean crustal growth: constraints from zircon U-Pb dating and Hf isotope. Acta Petrologica Sinica, 29(7): 2537-2550. (in Chinese with English abstract)
Geng Y S, Wan Y S, Shen Q H, et al. 2000. Chronological framework for early Precambrian major geological events in Lüliang area. Acta Geologica Sinica, (3):216-223. (in Chinese)
Geng Y S, Wan Y S, Yang C H. 2003. The Palaeoproterozoic rift-type volcanism in Lüliangshan area, Shanxi Province, and its geological significance. Acta Geoscientica Sinica, (2): 97-104. (in Chinese with English abstract)
Geng Y S, Wan Y S, Yang C H. 2008. A comprehensive study report on Paleoproterozoic system in China-determination of major Paleoproterozoic geological events in Lüliang area and preliminary discrimination of paleoproterozoic. Beijing: Geological Publishing House, 515-533. (in Chinese)
Glasby G P, Schulz H D. 1999. Eh, pH diagrams for Mn, Fe, Co, Ni, Cu and as under seawater conditions: application of two new types of the Eh, pH diagrams to the study of specific problems in marine geochemistry. Aquatic Geochemistry, 5(3): 227-248.
Gross G A. 1991. Genetic concepts for iron-formation and associated metalliferous sediments. Economic Geology Monograph, (8): 51-81.
Han T M. 1988. Origin of magnetite in Precambrian iron-formations of low metamorphic grade//IAGOD Quadrennial Symposium, 7th, Proceedings, 641-656.
He H. 2013. Discussion on formation conditions of sedimentary metamorphic iron deposit in Yuanjiacun, Lan County, Shanxi Province. Huabei Land and Resources, (3): 89-91. (in Chinese)
Jackson S E, Pearson N J, Griffin W L, et al. 2004. The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U-Pb zircon geochronology. Chemical Geology, 211(1): 47-69.
James H L. 1954. Sedimentary facies of iron-formation. Economic Geology, 49(3): 235-293.
Liu M J. 2013. Hydrothermal metasomatism and its metallogenic significance of the Gongchangling iron deposit, Liaoning: master's degree thesis. Beijing: China University of Geosciences. (in Chinese with English abstract)
Liu T B, Zhao Y R. 2004. Metallogenesis of the Lüliang terrane and the Wutai terrane. Journal of Taiyuan University of Technology, (5): 618-621. (in Chinese)
Ludwig K R. 2001. User's manual for Isoplot /Ex Rev. 2.4. Berkeley: Berkeley Geochronology Center Special Publication, 56.
Regional Geological Survey Team of Shanxi Provincial of Geology and Mineral Resources (RGST). 1975. Summary of regional mineral resources in Shanxi Province. Yuci: RGST.
Schwertmann U, Murad E.1983. Effect of pH on the formation of goethite and hematite from ferrihydrite. Clays and Clay Minerals, 31(4): 277-284
Shen B F, Song L S, Li Z H. 1982. Analysis of sedimentary facies and formation conditions of Yuanjiacun iron construction in Lan County, Shanxi. Journal of Changchun University of Earth Sciences, (S1): 31-51,166. (in Chinese)
Shen Q H. 1998. Geological characteristics and formation background of Early Precambrian banded ferric rocks in North China Platform. Beijing: Geological Publishing House, 1-30. (in Chinese)
Song B, Zhang Y H, Wan Y S, et al. 2002. Zircon SHRIMP sample target production, age determination and discussion of related phenomena. Geological Review, 48(S1): 26-30. (in Chinese)
Taylor D, Delstra H J, Harding A E, et al. 2001. Genesis of high-grade hematite orebodies of the Hamersley Province, Western Australia. Economic Geology, 96: 837-873.
Trendall A F, Morris R C. 1983.Iron-formation, facts and problems. Amsterdam: Elsevier, 1-11.
Wang C L, Zhang L C, Lan C Y, et al. 2012. Geochemical characteristics and genesis of Yuanjiacun iron ore in Lüliang, Shanxi. Mineral Deposits, 31(S1): 129-130. (in Chinese)
Wang C L, Zhang L C, Lan C Y, et al. 2014. BIF REE geochemistry of the Paleoproterozoic Yuanjiacun iron deposit in Lüliang, Shanxi and its indication for major oxidation events. Science China Earth Sciences, 44(11): 2389-2405.
Wang C L, Zhang L C, Lan C Y, et al. 2015. Analysis of sedimentary facies and depositional environment of the Yuanjiacun banded iron formation in the Lüliang area, Shanxi Province. Acta Petrologica Sinica, 31(6): 1671-1693. (in Chinese with English abstract)
Wang X M, Yang K G, Sun S F, et al. 2011. The structure and composition of ferrihydrite and its environmental geo-chemical behaviors. Earth Science Frontiers, 18(2): 339-347. (in Chinese with English abstract)
Xu C L, Zhu G X, Tan Y L, et al. 2008. Division of Precambrian strata in Lüliang mountainous area. Geological Review, (4): 459-465.
Yu J H, Wang D Z, Wang C Y, et al. 1997. Zircon U-Pb age of Shanxi Lüliang group and its main metamorphism. Geological Review, (4): 403-408. (in Chinese)
Zhu J C, Zhang F S. 1987. Forming conditions of Precambrian iron deposit in Yuanjiacun mining area, Shanxi. Mineral Deposits, (1): 11-21. (in Chinese)
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