HR: 1340h
AN: V13E-0580    [Abstracts]
TI: The Mesozoic rock-forming and ore-forming processes and tectonic environment evolution from Shanghang-Datian region, Fujian, SE China
AU: * Hu, Q
EM: njhqing@cgs.gov.cn
AF: Hu Qing, 534 East Zhongshan Road, Nanjing, JS 210016 China
AU: Mao, J
EM: mjrmh@sina.com; jianrenm@hotmail.com
AF: Hu Qing, 534 East Zhongshan Road, Nanjing, JS 210016 China
AB: There are the Mesozoic large-scale magmatism and the mineralization in South China. As amajor part of East Asian, South China continent is an extremely complex region, involving the multi-stages of the Mesozoic tectono-magmatic activity. Therefore, various patterns have been proposed in the recent 20 years. There are various isotopic ages for four granitic plutons in the studied area, which respectively are below: Tangquan pluton 185-158Ma; Zijinshan pluton 157-145Ma; Caixi pluton 133Ma; Sifang pluton 108-105. Tangquan and Zijinshan plutons are belonged to respectively Early-Middle-Jurassic and Late-Jurassic in Early-Mesozoic, and Caixi and Sifang plutons are belonged to Early-Cretaceous in Late-Mesozoic. Both Tangquan and Sifang plutons, which are the metaluminous granites with A/CNK<1.0, are regarded as to possess the geochemical characteristics of adakite rich in Sr, Ba and poor in HREE, Y, Yb, and as the most potential host rocks of ore-bearing for the copper deposit. Zijinshan pluton is regarded as peraluminous granites with A/CNK>1.1,and possesses the geochemical feature of crust-derived mud materials by partial melting with enrichment in K, Rb, Th, Y, HREE and depletion in Sr, Ba, Ti. Caixi pluton is weak-peraluminous granites with A/CNK=1.0-1.1, and its geochemical feature lies between the Zijinshan pluton and Sifang pluton. Tangquan pluton with higher Na2O content, which was formed by partial melting of the thicken lower-crust derived basic rock corresponding to Proterozoic, resulting from the underplating of mantle-derived basic magma, is major host rocks of the metallogenic series of copper, iron and polymetallic deposits. Sifang pluton with higher K2O content, which was mixed between granite magmas of middle-lower crust-derived by partial melting and mantle-derived basic magma with high K, resulted in increment of K2O content in the melt and obtained a large number of copper, other metals and sulphur from mantle, is major host rocks of the metallogenic series of the porphyry copper, gold and polymetallic deposits. There have been the petrological records of lithosphere extension since Early-Middle-Jurassic (180Ma) in the region, and formation of Zijinshan peraluminous granites is resulted from the extension mechanism. With the time past, the lithosphere extension-thinning and underplating is increased gradually. The contribution of mantle to granite formation is increased gradually.
DE: 1020 Composition of the continental crust
DE: 1744 Tectonophysics
DE: 1749 Volcanology, geochemistry, and petrology
SC: Volcanology, Geochemistry, Petrology [V]
MN: Fall Meeting 2005