琼西晚二叠世花岗岩的成因及其大地构造意义  

Petrogenesis of Late Permian granites from West Hainan Island and its geotectonic implications

作　　者：欧阳杰婷 周云 刘希军[1,2,3] 李政林[1,3] 解宇航 蔡永丰[1,3] Ouyang Jieting;Zhou Yun;Liu Xijun;Li Zhenglin;Xie Yuhang;Cai Yongfeng(Guangxi Key Laboratory of Hidden Metallic Ore Deposits Exploration,Guilin University of Technology,Guilin,Guangxi 541004;Collaborative Innovation Center for Exploration of Nonferrous Metal Deposits and Efficient Utilization of Resources,Guilin University of Technology,Guilin,Guangxi 541004;Guangxi Science Innovation Base for Formation and Exploration of Strategic Critical Mineral Resources,Guilin University of Technology,Guilin,Guangxi 541006)

机构地区：[1]广西隐伏金属矿产勘查重点实验室,桂林理工大学,广西桂林541004 [2]有色金属矿产勘查与资源高效利用协同创新中心,桂林理工大学,广西桂林541004 [3]广西战略性关键矿产资源成矿与勘查科技创新基地,桂林理工大学,广西桂林541006

出　　处：《地质科学》2025年第1期212-228,共17页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：国家自然科学基金项目(编号:42473063);广西自然科学基金项目(编号:2022GXNSFAA035620);广西重点研发计划项目(编号:桂科AB22035045)资助。

摘　　要：为了探讨海南岛西部晚古生代时期的构造演化特征,本文对琼西出露的花岗岩开展了系统的岩石学、同位素年代学和岩石地球化学研究。LA-ICP-MS锆石U-Pb定年结果显示,来自琼西的两个代表性花岗岩的形成时代分别为255.4±1.7 Ma和255.4±1.2 Ma,为晚二叠世岩浆活动的产物。地球化学分析结果表明,上述晚二叠世花岗岩具有高硅、富碱及弱过铝质特征;相对富集大离子亲石元素、亏损高场强元素,具有明显的Eu负异常,整体表现出高分异I型花岗岩的特征。岩石的形成主要与地壳物质的部分熔融有关,同时也有少量地幔物质的加入,并在成岩过程中经历了分离结晶作用。综合分析认为海南岛西部晚二叠世花岗岩的形成与东古特提斯洋的俯冲作用有关。To investigate the Late Paleozoic tectonic evolution of Hainan Island,this study conducted a systematic petrological,isotopic geochronological,and geochemical analyses of the granites exposed in the western region of Hainan Island.LA-ICP-MS zircon U-Pb dating results indicate that the formation ages of two representative granites from the western region of Hainan Island are 255.4±1.7 Ma and 255.4±1.2 Ma,respectively,which are products of Late Permian magmatic activity.The granites exhibit high-silica,alkali-rich,and weakly peraluminous characteristics;they are relatively enriched in large ion lithophile elements and depleted in high field strength elements,with a distinct negative Eu anomaly,overall displaying the characteristics of highly fractionated Ⅱ-type granites.The formation of the rocks is primarily derived from partial melting of crustal materials,with a minor addition of mantle materials,and has undergone fractional crystallization during the process of magma evolution.Comprehensive analysis suggests that the formation of the Late Permian granites in the western part of Hainan Island is related to the subduction of the east Paleo-Tethys Ocean.

关 键 词：二叠纪 Ⅰ型花岗岩 锆石U-PB定年 岩石地球化学 东古特提斯 海南岛 

分 类 号：P581[天文地球—岩石学] P597[天文地球—地质学]