江西金滩岩体花岗岩的侵位深度——来自白云母矿物化学成分的约束  

The emplaced depth of the granite from Jintan pluton:Constraints from mineral chemistry of muscovite

作　　者：陶继华[1,2,3] 杨跃贵 张吉源 石争 许德如 TAO Ji-hua;YANG Yue-gui;ZHANG Ji-yuan;SHI Zheng;XU De-ru(School of Earth Science,East China University of Technology,Nanchang 330013,China;State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China;Jiangxi Province Key Laboratory of the Causes and Control of Atmospheric Pollution,East China University of Technology,Nanchang 330013,China)

机构地区：[1]东华理工大学地球科学学院,江西南昌330013 [2]东华理工大学核资源与环境国家重点实验室,江西南昌330013 [3]东华理工大学江西省大气污染成因与控制重点实验室,江西南昌330013

出　　处：《岩石矿物学杂志》2024年第4期847-855,共9页Acta Petrologica et Mineralogica

基　　金：国家自然科学基金(41963002,42063001);江西省大气污染成因与控制重点实验室开放基金(AE2104)。

摘　　要：白云母是过铝质花岗岩中常见的矿物,可以用来作为限制岩体侵位深度的压力计矿物。文章利用电子探针对金滩二云母花岗岩中的白云母进行了化学成分分析,通过白云母结晶压力计算获得金滩岩体的侵位压力为4.9×10^(8)~6.1×10^(8)Pa,平均5.4×10^(8)Pa,对应的侵位深度为16~20 km,平均18 km。综合前人研究成果认为,华南印支期花岗岩侵位深度普遍为17~19 km,且华南印支期造山加厚的地壳厚度很可能≥50 km,而在燕山期经历了强烈的风化剥蚀去顶作用。这一认识为揭示华南地区相对缺乏印支期火山岩提供了一种新的解释。Muscovite is a common mineral in peraluminous granites,it could be a mineral barometer to constrain the emplacement depth of peraluminous granites.Chemical compositions of muscovite from the Jintan two-mica granite are determined using electron microprobe.According to the calculation for the crystallization pressure of the muscovite,the pressure of emplacement of the Jintan pluton is 4.9×10^(8)~6.1×10^(8)Pa with average 5.4×10^(8)Pa,corresponding to 16~20 km with average 18 km in depth.Combing with previous studies,we suggest that the emplace depth is 17~19 km,and we can presume that crustal thickness of South China in the Indosinian period was likely≥50 km,but it may be denudated because of extensive weathering in the Yanshanian period,which can be a new explanation for the lacking Indosinian volcanic rocks in South China.

关 键 词：华南 花岗岩 金滩岩体 白云母 侵位深度 

分 类 号：P588.121[天文地球—岩石学] P578.959[天文地球—地质学]