中国南天山晚石炭世—早二叠世花岗质侵入岩的岩石成因与地壳增生

晚石炭世—早二叠世在中亚南天山造山带形成了大量的花岗质侵入岩.中国境内这些岩体以晚石炭世Ⅰ型花岗岩、早二叠世Ⅰ型和S型花岗岩以及最晚期的A型花岗岩为代表.不同类型的岩石在源区特征和岩浆形成的温压条件上存在一定的差异,而这些差异性反映了该时期内构造环境的演化过程.本文选取铁列克岩体、盲起苏岩体、英买来岩体、川乌鲁杂岩体、...

Petrogenesis of Late Carboniferous to Early Permian Granitoid Plutons in the Chinese South Tianshan: Implications for Crustal Accretion

Abstract: A large volume of granitoid plutons formed during late Carboniferous to early Permian in the South Tianshan Orogenic belt. These rocks can be generally classed as Late Carboniferous I-type granites, Early Permian I and S-type granites, and A-type granites that formed at ~275Ma. In this paper, seven granitoid plutons, including Tielieke pluton, Mangqisu pluton, Yingmailai pluton, Chuanwulu pluton, Baleigong pluton, Huoshibulake pluton and Mazhashan pluton, in the Chinese South Tianshan Orogenic belt are chosen for geochronological, petrological, and geochemical investigations. Tielieke and Mangqisu plutons are Late Carboniferous I-type granites. The magmas, representing the syn-collisional granitoid magmatism, derived from the metaigneous rocks in lower crust. The Early Permian S-type granite is represented by Yingmailai pluton, which is indicative of the remelting of Mesoproterozoic metasedimentary and metaigneous rock induced by the radiogenic heating. Felsic rocks in Chuanwulu pluton are I-type granites, representing the hybrid magmas that derived from the lower part of the thickened continental crust. The source of mafic rocks in the Chuanwulu pluton is a metasomatized lithospheric mantle. The nature of Yingmailai and Chuanwulu plutons suggests a transitionary setting between syn-collisional setting and post-collisional setting. A-type granites, which are generally have ages of ~275Ma, indicate the interaction between asthenosphere and lower crust. Baleigong pluton is A2-type, representing the epilogue of the post-collisional setting; however, Huoshibulake and Mazhashan plutons are A1-type and associated with the rift regime.