华南地质2024，Vol.40Issue(2)：353-364,12.DOI:10.3969/j.issn.2097-0013.2024.02.011
粤北新丰早侏罗世芹菜塘岩体年代学、地球化学特征及构造意义
Geochronology,Geochemical Characteris-tics and Tectonic Setting of the Early Jurassic Qincaitang Pluton in Xinfeng,Northern Guang-dong Province
摘要
Abstract
To further study the characteristics of the Early Jurassic tectono-magmatic activities in South Chi-na,this paper conducts geochemical analysis and zircon U-Pb age dating on the Qincaitang pluton in the Xin-feng area of Northern Guangdong province.The SHRIMP zircon U-Pb dating result for the Qincaitang grano-diorite is 191.8±2.3 Ma,and the LA-ICP-MS zircon U-Pb dating result for the dioritic porphyrite veins devel-oped in the outer contact zone is 190.4±3.3 Ma,both of which belong to the Early Jurassic period.Geochemi-cal studies suggest that the rocks are characterized by quasi-alumina,high potassium calc-alkaline,with en-richment of large iron lithophile elements such as Rb and Th,as well as rare earth elements La,Ce and Nd.The rocks are relatively depleted in Ba,Sr,Nb,Ta,P and Ti with obvious Th-U peak,La-Ce peak and Ta-Nb trough,showing that rocks experienced magma crystallization differentiation during the diagenetic process,forming I-type granite from the basaltic rock melting in the lower crustal tectonic environment.This research indicates that the ancient Pacific plate subduction was probably initiated in the Early Jurassic,and therefore,South China was influenced by the Pacific tectonic domain during the Early Mesozoic,making the"intermit-tent period"of magmatic activity unlikely occur during the two major tectonic regime transitions in the Early Mesozoic.关键词
早侏罗世岩浆岩/U-Pb年代学/地球化学/芹菜塘岩体/粤北Key words
Early Jurassic magmatic rock/U-Pb geochronology/geochemistry/Qincaitang intrusion/North-ern Guangdong Province分类
地质学引用本文复制引用
张献河,娄峰,李宏卫,付潮罡,韦秋妮..粤北新丰早侏罗世芹菜塘岩体年代学、地球化学特征及构造意义[J].华南地质,2024,40(2):353-364,12.基金项目
广东省地质勘查与城市地质专项项目(NO.2023-15) （NO.2023-15）
中国地质调查局项目(NO.12120113063100) （NO.12120113063100）
