Geology and Genesis of Peraluminous Granites in East Tianshan Upper Paleozoic Island Arc Belt

作     者：顾连兴 杨浩 严正富 廖静娟 王金珠 

作者机构：Department of Earth Sciences Nanjing University Nanjing Geological Team No. 6 Xinjiang Bureau of Geology and Mineral Resources Hami Xinjiang 

出 版 物：《Chinese Journal Of Geochemistry》 (中国地球化学学报)

年 卷 期：1996年第15卷第1期

页      面：33-43页

核心收录：

学科分类：0709[理学-地质学] 070901[理学-矿物学、岩石学、矿床学] 07[理学] 

主　　题：花岗岩 弧形岛 天山地区 古生代 成因 地质构造 

摘      要：A peraluminous granite belt occurs along the connecting zone between the TurPan-Hami Precambrian block and the Upper Paleozoic island arc belt. Muscovite granite and two-mica granite are the essential lithological components of that belt. All the potassium feldspars inthese granites are microcline. Heavy minerals are dominated by magnetite. SiO2 contents ofthese granites are greater than 73 % with most of the A/NKC values greater than 1.1, norma-tive corundum values greater than 1. Plots of CIPW norms in the (AL-K-Na)-Ca-(Fe2++ Mg)diagram are mostly situated in the plagioclase-cordierite-muscovite region. The rocks are char-acterized by very low contents of minor elements and ΣREE with strong Eu depletion, δ18Ovalues between 6. 69‰ and 7. 0‰, Rb-Sr isochron age of 260. 2 ± 6. 2 Ma and an initial 87Sr/86Sr ratio of 0. 7052. These granites might have been produced by partial melting of moderatelyacidic volcanites and low-maturity sediments in the basement sequences and could be geneticallyconnected with the southward A-type subduction of the Turpan-Hami block following the clo-sure of the Middle Carboniferous back-arc basin.