Geochemistry, geochronology and zircon Hf isotope of Wangxian granodiorite-porphyry in eastern Hunan Province and its geological significance

被引：7
|
作者：
Yang L. [1 ,2 ]
Wu X. [1 ,2 ]
Hu B. [1 ,2 ]
Li J. [1 ,2 ]
Wang X. [1 ,2 ]
机构：
[1] Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Ministry of Education, Central South University, Changsha
[2] School of Geosciences and Info-Physics, Central South University, Changsha
来源：
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | 2018年 / 49卷 / 09期
关键词：
Eastern Hunan Province; Hf isotope; Indosinian period; Wangxian granodiorite-porphyry; Zircon U-Pb dating;
D O I：
10.11817/j.issn.1672-7207.2018.09.022
中图分类号：
学科分类号：
摘要：
The Wangxian granodiorite-porphyry is exposed at the eastern Hunan Province, rock element mass fraction and zircon Pb-Hf isotopes were studied by geochemical methods and geochronology. The results show that the Wangxian granodiorite-porphyry is characterized by strongly peraluminous composition and high potassium Ca-alkalineseries with high w(SiO2) (74.46%-75.79%) and w(Al2O3) (12.47%-12.83%), and low w(TFe2O3) (0.96%-1.09%), w(MgO) (0.17%-0.27%) and w(Na2O)/w(K2O)(0.39-0.57). The trace elements of the Wangxian granodiorite-porphyry has low total REE contents, strong enrichment of Rb, Th, U, K, Nd, Hf and Sm, and relative depletion of Ba, Eu, Sr, Ti and P-REE distribution curve presents as four groups of different curves. The emplacement age of the Wangxian granodiorite-porphyry is determined in (224.7±4.4) Ma. The primary zircons have uniform and negative εHf(t) (-6.83- -3.44), which indicates that the Wangxian granodiorite-porphyry belongs to S-type granites, and is formed by partial melting of mesoproterozoic crustal material of the Cathaysia block and mixed with some mantle-sourced magma. The magma experiences a strong crystal fractionation process. Combined with the Indosinian period tectonic development of South China, the Wangxian granodiorite-porphyry formed in an extensional rift intraplate environment, which is related to the closure of the paleo-Asian Ocean and NW-trending flat subduction of paleo-Pacific plate. The extensional setting induces the underplating of the basaltic magma, leading to partial melting of crustal rocks. © 2018, Central South University Press. All right reserved.
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页码：2280 / 2291
页数：11
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