Petrogenesis and Tectonic Significance of Silurian Intermediate-Acid Intrusive Rocks in the Xiemisitai Area,West Junggar
Zhang Yejun
Lv Huili
Wang Guoqing
Li Shengfu
Yang Qingmao
Yin Song
Yang Wenlong
Wei Hu
Gao Qi
Guo Huanqing
Li Yilong
Abstract：There are abundant Paleozoic intermediate-acid intrusive rocks in the Xiemisitai area,West Junggar,which is a hotspot for the study of crustal accretion of the Central Asian Orogenic Belt.In this study,detailed petrology,geochemistry,zircon U-Pb geochronology and Hf isotopic composition analysis were conducted for the intrusive rocks in the Wushijiagayiti gold deposit area in the western section of Xiemisitai.The results show that the intrusive rocks mainly consist of monzonites and quartz monzonites,with zircon U-Pb ages ranging from 429 to 424 Ma,εHf(t)values ranging from+11.7 to+15.2,and Hf isotope model ages of tDM2 of ca.560 Ma.The monzonites and quartz monzonites have similar geochemical characteristics belonging to high-K calc-alkaline to shoshonitic series and are enriched in Rb,K,Zr and Hf,depleted Nb,Ta,P and Ti.All of them are typical of I-type granitoids and show continental arcaffinity.According to comprehensive research,it is inferred that the intermediate-acid intrusive rocks in the western section of the Xiemisitai area were derived from partial melting of young mafic lower crust in a volcanic arc setting during the northward subduction of the Junggar-Balkhash Ocean in the early Paleozoic.They recorded the transformation from a basaltic intra-oceanic arc to a continental arc during crustal growth.
Keywords：intermediate-acid intrusive rocksXiemisitai volcanic arcmagmatismWest JunggarCentral Asian Orogenic Beltgeochemistry
Publication Date：2025-08-30
Online Publishing Date：2025-08-22(First online date of this platform, not the publication date of the document)
Pages：21( 3013-3033 )