摘要
Various isotopic ages were reported for four granite plutons in the area studied, i.e., the Tangquan pluton (185-158 Ma); the Zijinshan pluton (157-145 Ma); the Caixi pluton (133 Ma); and the Sifang pluton (108-105 Ma). The Tangquan and Zijinshan plutons belong to Early-Middle Jurassic and Late Jurassic of Early-Mesozoic respectively, and the Caixi and Sifang plutons belong to Early-Cretaceous of Late Mesozoic. Both the Tangquan and Sifang plutons, which are the metaluminous granites with A/CNK<{1.0}, are considered to possess the geochemical characteristics of adakite rich in Sr, Ba and poor in HREE, Y, Yb, and are regarded as the most potential host rocks of copper ores. The Zijinshan pluton is regarded as a peraluminous granite with A/CNK>{1.1}, and possesses the geochemical features of crust-derived muddy materials resultant from partial melting with enrichments in K, Rb, Th, Y, HREE and depletions in Sr, Ba, and Ti. The Caixi pluton is a weakly peraluminous granite with A/CNK={1.0}-{1.1}, and its geochemical characteristics are intermediate between the Zijinshan pluton and the Sifang pluton. The Tangquan pluton with higher Na-2O contents, which resulted from partial melting of Proterozoic thick lower-crust derived basic rocks in response to underplating of mantle-derived basic magma, is one of the major host rocks of the metallogenic series of copper, iron and polymetallic deposits. The Sifang pluton with higher K-2O contents, which was mixed between middle-lower crust-derived granite magma by partial melting and mantle-derived high-K basic magma, giving rise to the increment of K-2O in the melt, and extracted large amounts of copper and other metals, as well as sulphur, is one of the major host rocks of the metallogenic series of porphyry copper, gold and polymetallic deposits. Petrological records have shown that there has occurred lithosphere extension since the Early-Middle Jurassic (180 Ma) in the region, and the formation of Zijinshan peraluminous granite is ascribed to the extension mechanism. With th
Various isotopic ages were reported for four granite plutons in the area studied, i. e. , the Tangquan pluton （ 185 - 158 Ma） ; the Zijinshan pluton （ 157 - 145 Ma） ; the Caixi pluton （ 133 Ma） ; and the Sifang pluton （ 108 - 105 Ma）. The Tangquan and Zijinshan plutons belong to Early-Middle Jurassic and Late Jurassic of Early-Mesozoic respectively, and the Caixi and Sifang plutons belong to Early-Cretaceous of Late Mesozoic. Both the Tangquan and Sifang plutons, which are the metaluminous granites with A/CNK 〈 1.0, are considered to possess the geochemical characteristics of adakite rich in Sr, Ba and poor in HREE, Y, Yb, and are regarded as the most potential host rocks of copper ores. The Zijinshan pluton is regarded as a peraluminous granite with A/CNK 〉 1.1, and possesses the geochemical features of crusterived muddy materials resultant from partial melting with enrichments in K, Rb, Th, Y, HREE and depletions in Sr, Ba, and Ti. The Caixi pluton is a weakly peraluminous granite with AVCNK = 1.0 - 1.1, and its geochemical characteristics are intermediate between the Zijinshan pluton and the Sifang pluton. The Tangquan pluton with higher Na20 contents, which resulted from partial melting of Proterozoic thick lower-crust derived basic rocks in response to underplating of mantle-derived basic magma, is one of the major host rocks of the metallogenic series of copper, iron and polymetallic deposits. The Sifang pluton with higher K20 contents, which was mixed between middle-lower crust-derived granite magma by partial melting and mantle-derived high-K basic magma, giving rise to the increment of K20 in the melt, and extracted large amounts of copper and other metals, as well as sulphur, is one of the major host rocks of the metallogenic series of porphyry copper, gold and polymetallic deposits. Petrological records have shown that there has occurred lithosphere extension since the Early-Middle Jurassic （ 180 Ma） in the region, and the formation of Zijinshan peraluminous granite is ascribed
基金
ThisresearchwasfinanciallysupportedbytheChinaGeologicalSurvey(No.1212010611805).
关键词
花岗岩
中生代
镁
铜
金属混合物
福建
矿化过程
granite
Mesozoic
ore-forming process
tectonic environment
southwestern Fujian
