华南和喜马拉雅高分异花岗岩地球化学特征对比分析  

Comparison of the geochemical characteristics of highly fractionated granites in South China and the Himalaya

作　　者：张睿泽 左仁广[1] ZHANG RuiZe;ZUO RenGuang(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(Wuhan),Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉)地质过程与成矿预测全国重点实验室,武汉430074

出　　处：《岩石学报》2025年第4期1424-1441,共18页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(42172326)资助.

摘　　要：铌钽等稀有金属关键战略性矿产资源通常与高分异花岗岩伴生。华南和喜马拉雅是我国高分异花岗岩分布最广的地区,探究这两个地区的高分异花岗岩在成因、分异程度等方面的差异,对深入理解区域成矿动力学背景及与之有关的稀有金属找矿勘查具有重要意义。本文收集并筛选了国内外学者发表的华南和喜马拉雅高分异花岗岩地球化学数据,采用多种划分标准构建了华南和喜马拉雅高分异花岗岩数据集,并通过数据驱动的方法探究了华南和喜马拉雅高分异花岗岩在主、微量元素和同位素方面存在的差异。同时,建立了基于数据驱动的随机森林高分异花岗岩判别模型。发现Nb、Hf、Al_(2)O_(3)、Th与Zr等是区分两个地区高分异花岗岩的主要元素,反映出两个地区花岗质岩浆在分异过程中不同矿物分离结晶所导致的差异。此外,本文还基于这些元素之间的比值进行判别分析,发现(Hf+Th+Nb)/Zr和(Hf+Nb)/Zr等指标对华南与喜马拉雅高分异花岗岩的划分起到重要作用。Rare-metal minerals such as Nb and Ta are the key strategic resources,and often associated with highly fractionated granites.South China and the Himalaya are the most widely distributed regions of highly fractionated granites in China.Investigating the differences in genesis,fractionation,and other aspects of highly fractionated granites in these two regions is of great significance for a deeper understanding of regional metallogenic dynamics and related rare-metal prospecting.In this study,we collected and selected geochemical data of highly fractionated granites of South China and the Himalaya from publications both domestically and internationally.By adopting multiple division criteria,a dataset of highly fractionated granites from South China and the Himalaya was established.Data-driven methods were used to investigate the differences of major and trace elements and isotopes in the highly fractionated granites from South China and the Himalaya.Moreover,a random forest discriminant model based on a data-driven perspective was established to classify the two regions high differentiation granites.It reveals that elements such as Zr,Hf,Al_(2)O_(3),Th,and Nb are the main distinguishing factors between the two regions highly fractionated granites.These elements may reflect the differences caused by the separation and crystallization of different minerals during the differentiation process of granitic magmas between the two regions.Additionally,this study conducts model discrimination analysis based on the ratios of these elements,finding that indicators such as(Hf+Th+Nb)/Zr and(Hf+Nb)/Zr play crucial roles in the classification of highly fractionated granites of South China and the Himalaya.

关 键 词：华南 喜马拉雅 高分异花岗岩 机器学习 

分 类 号：P595[天文地球—地球化学] P588.121[天文地球—地质学]