Late Mesozoic intrusive complexes in the coastal area of Fujian, SE China: the significance of the gabbro-diorite–granite association
Late Mesozoic intrusive complexes in the coastal area of Fujian, SE China: the significance of the gabbro-diorite–granite association
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DOI：
10.1016/s0024-4937(98)00087-5
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发表时间：
1999-02
期刊：
影响因子：
3.5
通讯作者：
Xi‐sheng Xu;C. Dong;Wuxian Li;Xinmin Zhou
中科院分区：
文献类型：
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作者：
Xi‐sheng Xu;C. Dong;Wuxian Li;Xinmin Zhou
平潭和代千山火成岩杂岩体是发育于活动大陆边缘的典型钙碱性系列。这两个杂岩体以花岗岩或辉长岩为主，少量闪长岩和花岗闪长岩，在时间和空间上紧密共存。辉长岩的主微量元素特征表明，辉长岩是由交代上地幔产生的高铝玄武岩岩浆结晶而成。典型的铝质钙碱性组成、微量元素模式和Sr-Nd同位素表明，杂岩体中的花岗岩为i型花岗岩，可能是深部地壳受地幔热贡献形成的。野外关系、岩石学和地球化学有利于高铝玄武岩岩浆和花岗质岩浆之间的机械混合和有限的化学混合，导致闪长岩或花岗闪长岩的形成。这些杂岩的双峰特征反映了晚中生代太平洋板块在欧亚大陆下的俯冲作用所诱发的弧后伸展岩浆活动的总体特征。
The Pingtan and Daiqianshan igneous complexes, southeastern China, are typical of calc-alkaline series developed at active continental margins. These two complexes are dominated by granites or gabbros, with minor diorites and granodiorites, and these rock types closely coexisted both temporally and spatially. The major and trace element signatures of gabbros indicate they were crystallised from high aluminium basaltic magmas, which were generated from metasomatised upper mantle. The typical metaluminous calc-alkaline composition, trace element patterns and Sr–Nd isotopes indicate the granites in the complexes are I-type granites, which may have been generated from the deeper crust by a thermal contribution from the mantle. Field relationships, petrography and geochemistry favour a mechanical mingling together with a limited chemical mixing between high aluminium basaltic magma and granitic magma, resulting in the formation of diorites or granodiorites. The essentially bimodal character of these complexes reflects the general character of back-arc extensional magmatism, which was induced by the subduction of the Pacific plate beneath the Eurasian continent in late Mesozoic time.