Geochemistry and Sr-Nd-Pb Isotopes of the Granites from the Hashitu Mo Deposit of Inner Mongolia, China： Constraints on Their Origin and Tectonic Setting  

作　　者：DING Chengwu DAI Pan BAGAS Leon NIE Fengjun JIANG Sihong WEI Junhao DING Chengzhen ZUO Pengfei ZHANG Ke 

机构地区：[1]MLR Key Laboratory of Metallogeny and Mineral Assessment,Institute of Mineral Resources,Chinese Academy of Geological Sciences,Beijing 100037,China [2]Faculty of Earth Resources,China University of Geosciences(Wuhan),Wuhan 430074,Hubei,China [3]School of Earth and Environment,The University of Western Australia,35 Stirling Highway,Crawley,Western Australia 6009 [4]Geophysical Research Institute of BGP Inc.China National Petroleum Corporation,Zhuozhou 072751 Hebei,China [5]School of the Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China

出　　处：《Acta Geologica Sinica(English Edition)》2016年第1期106-120,共15页地质学报（英文版）

基　　金：part of the ongoing project "Superimposed tectonic activities and large-scale oreforming processes of the Hinggan-Mongolia Orogenic Belt";financially supported by the State Basic Research Program of China(2013CB429805)

摘　　要：The Hashitu molybdenum deposit is located in the southern part of the Great Hinggan Range, NE China. Molybdenum mineralization is hosted by and genetically associated with monzogranite and porphyritic syenogranite. Sr-Nd-Pb isotopes of the intrusions show that the porphyritic syenogranite has initial ^87Sr/^86Sr ratios of 0.70418-0.70952, ENd（t） values of 1.3 to 2.1 （t=143 Ma）, ^206Pb/^204Pb ratios of 19.191-19.573, ^207Tpb/^204pb ratios of 15.551-15.572, and ^208Pb/^204Pb ratios of 38.826-39.143. The monzogranite has initial 87Sr/86Sr ratios of 0.70293-0.71305, εNd（t） values of 1.1 to 2.0 （t=-147 Ma）, ^206Pb/^204pb ratios of 19.507-20.075, ^207Pb/^204Pb ratios of 15.564-15.596, and ^208Pb/^204Pb ratios of 39.012-39.599. The calculated Nd model ages （TDM） for monzogranite and porphyritic syenogranite range from 866 to 1121 Ma and 795 to 1020 Ma, respectively. The granitic rocks in the Hashitu area have the same isotope range as granites in the southern parts of the Great Hinggan Range. The isotope composition indicates that these granites are derived from the partial melting of a juvenile lower crust originating from a depleted mantle with minor contamination by ancient continental crust. The integrating our results with published data and the Late Mesozoic regional tectonic setting of the region suggest that the granites in the Hashitu area formed in an intra-continent extensional setting, and they are related to the thinning of the thickened lithosphere and upwelling of the asthenosphere.The Hashitu molybdenum deposit is located in the southern part of the Great Hinggan Range, NE China. Molybdenum mineralization is hosted by and genetically associated with monzogranite and porphyritic syenogranite. Sr-Nd-Pb isotopes of the intrusions show that the porphyritic syenogranite has initial ^87Sr/^86Sr ratios of 0.70418-0.70952, ENd（t） values of 1.3 to 2.1 （t=143 Ma）, ^206Pb/^204Pb ratios of 19.191-19.573, ^207Tpb/^204pb ratios of 15.551-15.572, and ^208Pb/^204Pb ratios of 38.826-39.143. The monzogranite has initial 87Sr/86Sr ratios of 0.70293-0.71305, εNd（t） values of 1.1 to 2.0 （t=-147 Ma）, ^206Pb/^204pb ratios of 19.507-20.075, ^207Pb/^204Pb ratios of 15.564-15.596, and ^208Pb/^204Pb ratios of 39.012-39.599. The calculated Nd model ages （TDM） for monzogranite and porphyritic syenogranite range from 866 to 1121 Ma and 795 to 1020 Ma, respectively. The granitic rocks in the Hashitu area have the same isotope range as granites in the southern parts of the Great Hinggan Range. The isotope composition indicates that these granites are derived from the partial melting of a juvenile lower crust originating from a depleted mantle with minor contamination by ancient continental crust. The integrating our results with published data and the Late Mesozoic regional tectonic setting of the region suggest that the granites in the Hashitu area formed in an intra-continent extensional setting, and they are related to the thinning of the thickened lithosphere and upwelling of the asthenosphere.

关 键 词：granite Sr-Nd-Pb isotopes Hashitu Mo deposit Great Hinggan Range 

分 类 号：P618.65[天文地球—矿床学] P597[天文地球—地质学]