Petrological and Geochemical Constraints on the Origin of Strongly Peraluminous Granitoids from the Triassic Guangtoushan Pluton in South Qinling  

作　　者：GUAN Qi CAO Junlin WANG Rixiang XIE Peiling XIA Wenyue LI Xiaowei 

机构地区：[1]Hebei Key Laboratory of Strategic Critical Mineral Resources,Hebei GEO University,Shijiazhuang 050031,China [2]Hebei Province Collaborative Innovation Center for Strategic Critical Mineral Research,College of Earth Sciences,Hebei GEO University,Shijiazhuang 050031,China [3]Shandong Province Nuclear Industry Geological Group 273,Yantai,Shandong 264006,China [4]State Key Laboratory of Geological Process and Mineral Resources,School of Earth Science and Mineral Resources,China University of Geosciences,Beijing 100083,China [5]MNR Key Laboratory of Gold Mineralization Processes and Resources Utilization,Shandong Key Laboratory of Mineralization Geological Processes and Resources Utilization in Metallic Minerals,Shandong Institute of Geological Science,Jinan 250013,China [6]The Third Geological Exploration Institute of Qinghai Province,Xining 810029,China

出　　处：《Acta Geologica Sinica(English Edition)》2023年第6期1683-1697,共15页地质学报（英文版）

基　　金：funded by the State Key Program of National Natural Science of China(Grant No.41730426);the National Natural Science Foundation of China(Grant Nos.41872066,41702069 and 41602040);the Research Fund of Hebei Provincial Bureau of Geology and Mineral Resources(454-0601-YBN-DXXP)。

摘　　要：As an important part of the early Mesozoic granites in the South Qinling tectonic belt(SQTB),the Guangtoushan pluton provides a material basis for research on the composition of magma sources and the effects of peritectic assemblage entrainment(PAE)on the changes in the granite composition.As shown by the results of LA-ICP-MS zircon U-Pb dating,the Guangtoushan pluton was emplaced during the Late Triassic(214-212 Ma)and was formed in the post-collision stage between the SQTB and the Yangtze plate.The collected samples had high SiO_(2)content and low Cr and Ni contents,indicating that the magmas did not undergo significant crust-mantle mixing during their evolution.The Guangtoushan granitoids were distributed along the trend line of magmatic fractional crystallization in the F-An-Or diagram.This result,combined with the relatively homogeneous Sr-Nd isotopic composition,implies that the Guangtoushan pluton underwent slight assimilation and contamination.As can be inferred from the comparison between the compositions of the Guangtoushan granitoids and various fluid-absent experimental melts,the magma sources of the Guangtoushan granitoids contain a variety of materials,such as graywackes,pyroclastic graywackes,and pelites and are not derived from lower crustal mafic rocks.The correlation between the maficity and the major and trace elements further indicates that the strongly peraluminous granitoids from the Guangtoushan pluton was formed by the partial melting of biotite-bearing crustal rocks and its magmatic evolution was accompanied by the entrainment of clinopyroxenes and accessory minerals.

关 键 词：petrogenesis strongly peraluminous peritectic assemblage entrainment(PAE) Guangtoushan granitoids South Qinling 

分 类 号：P534.51[天文地球—古生物学与地层学] P588.121[天文地球—地质学]