Geochronology and tectonic setting of Pb¨CZn¨CMo deposits and related igneous rocks in the Yinshan region, Jinzhai, Anhui province, China

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• 作者：Xiao-chun  ; Xu^a ;   ; ^{xuxiaoch@sina.com} ; Jin-wei  ; Lou^a ;   ; ^b ; Qiao-qin  ; Xie^a ; Qiuxiang  ; Xiao^a ; Jianfeng  ; Liang^a ; San-ming  ; Lu^b
• 关键词：Isotopic age ; Mo and Pb&ndash ; Zn&ndash ; Mo deposit ; Igneous rock ; Yinshan region ; Jinzhai ; Anhui province
• 刊名：Ore Geology Reviews
• 出版年：2011
• 出版时间：December 2011
• 年：2011
• 卷：43
• 期：1
• 页码：132-141
• 全文大小：1919 K

文摘

The Gaijing Pb¨CZn¨CMo deposit and Shapinggou Mo deposit in the Yinshan region, Jinzhai, Anhui province, China, are hosted in various granitic intrusions with ⁴⁰Ar/³⁹Ar ages obtained for biotite and hornblende of 136.8 ¡À 1.6 Ma (medium-grained monzogranite), 130.4 ¡À 1.2 Ma (fine-grained granite), and 125.4 ¡À 1.0 Ma (fine-grained diorite). The modes of occurrence and cross-cutting relationships among the igneous intrusions indicate that alkali quartz-syenite and quartz-syenite porphyry (cryptoexplosive breccia) formed later than the calc-alkali monzogranite, granite, and diorite. Molybdenum mineralization occurs in pipe-like bodies hosted in cryptoexplosive breccia (pipe), quartz-syenite (porphyry), monzogranite, and granite, whereas Pb¨CZn mineralization occurs in veins distally from the Mo mineralization. The Re¨COs isotopic model ages of molybdenite from the Gaijing Pb¨CZn¨CMo deposit are 112.6 ¡À 1.3 and 113.5 ¡À 1.3 Ma, consistent with the ages of other molybdenum deposits throughout the East Qinling¨CDabie metallogenic belt. The geological characteristics and isotopic ages of the Gaijing Pb¨CZn¨CMo and Shapinggou Mo deposits indicate a genetic relationship to the emplacement of the quartz-syenite (porphyry) and to shallow-seated porphyry¨Ccryptoexplosive breccia intrusions. The present results, combined with existing data, suggest that the Pb¨CZn¨CMo deposits and related igneous rocks were formed in a geodynamic setting of regional lithospheric thinning, delamination, and thermal erosion in East China. The deposits are part of the East Qinling¨CDabie molybdenum belt, which in turn is part of a large-scale E¨CW-trending metallogenic belt in East China.