Geochemistry,Zircon U-Pb Age and Hf Isotope of the Huilanshan Granitoids in the North Dabie Terrane:Implications for Syn-Collapse Magmatism of Orogen

作     者：Shengxin Liu Haijin Xu 

作者机构：School of Earth SciencesChina University of Geosciences 

出 版 物：《Journal of Earth Science》 (地球科学学刊（英文版）)

年 卷 期：2019年第30卷第3期

页      面：636-646页

核心收录：

学科分类：07[理学] 0708[理学-地球物理学] 0704[理学-天文学] 

基　　金：supported by the National Natural Science Foundation of China (Nos. 41572039, 41772054, and 41372076) the Fundamental Research Funds for the Central Universities, China University of Geosciences (Wuhan) (No. CUGQYZX1704) 

主　　题：orogenic collapse magmatism partial melting lower continental crust Dabie Orogen 

摘      要：Syn-collapse magmatism is a critical issue for evolution of the continental *** Dabie Orogen is a typical orogen which was suffered from a complete *** kinds of granitoids,namely,the coarse-grained diorite and the fine-grained granite,are recognized at the center of the Luotian extensional dome,providing an opportunity to decipher the syn-collapse magmatism in the Dabie *** diorites(125±3 Ma)are high K calc-alkaline rocks,with low SiO2(51.9 wt.%–56.6 wt.%)and high MgO(3.5 wt.%–4.0 wt.%)*** are enriched in LREE and LILEs(e.g.,Ba,K,Rb)and depleted in HFSEs(e.g.,Ta,Nb,and Hf)with low ratio of Sr/Y(30.82–46.89).The granites(118±2 Ma)are shoshonite series rocks,with relatively high SiO2(68.9 wt.%–72.6 wt.%)and low MgO(0.32 wt.%–0.66 wt.%)*** are also enriched in LREE and LILEs with weakly negative Eu anomalies(δEu=0.81–0.85),and are depleted in HFSEs with low Sr contents(338 ppm–477 ppm)and Sr/Y ratios(23.80–33.13).Therefore,the two kinds of granitoids have no geochemical characteristics of adakitic rocks,suggesting that they were generated from a normal or thinned crust *** diorites have quite negative zirconεHf(t)values(-18.4 to-21.1),suggesting they were from partial melting of the mafic lower continental *** granites have relatively higher zirconεHf(t)values(-14.4 to-18.1).The granites also contains a series of old inherited zircon cores,such as two upper intercept ages of 2 628±41 and 1 840±37 Ma,and a concordant age of 807±9 *** these features suggest that the granites were generated from partial melting of the felsic middle-lower continental ***,the Huilanshan Early Cretaceous granitoids coupled with the Luotian extensional dome revealed the collapsed process of the Dabie Orogen.