摘要
燕山早期禾洞岩体位于南岭中段西侧,与印支期太保岩体及加里东期永和岩体构成粤西北连山地区多期次多阶段复式岩体。文章通过分析禾洞岩体的岩相学和地球化学特征,探讨其成因类型、源区性质、形成的构造背景及其与铀成矿的关系。研究表明,晚侏罗世的禾洞岩体主体岩性为正长花岗岩和二长花岗岩,局部为花岗闪长岩。正长花岗岩和二长花岗岩具高硅、富碱、过铝质、高钾钙碱性,负铕异常,相对富集大离子亲石元素Rb、U、Th、Pb、K,贫Sr、Ba,相对亏损高场强元素Zr、Hf、Nb、Ta、Ti的特征。禾洞岩体的岩相学和地球化学特征有别于A型和S型花岗岩,显示其为高分异I型花岗岩,且属于中等含铀-富铀岩体。不同岩性的岩石具相同的源区性质,为壳幔相互作用和岩浆不同程度结晶分异的产物。综合分析认为,禾洞岩体的形成与晚中生代古太平洋板块的俯冲构造背景有关,南岭地区强烈的岩石圈伸展作用诱发幔源岩浆沿先存的郴州—怀集等断裂底侵,导致古老地壳物质发生部分熔融。
The Early Yanshanian Hedong pluton is located in the midwest Nanling Mountain,which consit of the Indosinian Taibao pluton and the Caledonian Yonghe pluton in northwest Guangdong.The paper analyzed the petrographic and geochemical characteristics of the Hedong pluton,explored the genesis type,source properties,tectonic setting,and relationship with uranium deposits.The main rock types of the Hedong pluton in the Late Jurassic are syenogranite and diorite,with a small amount of granodiorite.The syenogranite and diorite are characterized by high silicon,alkali rich,peraluminous,high potassium calcium alkaline,negative Eu anomaly,relative enrichment of large ion lithophile elements such as Rb,U,Th,Pb,K,depletion of Sr and Ba,and relative depletion of high field strength elements such as Zr,Hf,Nb,Ta,Ti.The petrographic and geochemical characteristics of the puton are different from A-type and S-type granites,indicating that they are highly differentiated I-type granite and pluton with medium-high uranium content.Different lithologic type of the pluton have the same source properties and are the products of crust-mantle interactions and magma crystallization differentiation.Based on the regional geological background,it was believed that the formation of the Hedong pluton was related to the subduction of the Pacific plate during the Late Mesozoic.The intense lithospheric extension in the the Nanling Mountain area induced the underplating of mantle magma along the existing Chenzhou-Huaiji and other faults,resulting in partial melting of ancient crustal materials.
作者
张俊涛
杨戬
刘莉莉
柯信
胡智英
张玉
张跃跃
ZHANG Juntao;YANG Jian;LIU Lili;KE Xin;HU Zhiying;ZHANG Yu;ZHANG Yueyue(Research Center for Petrogenesis and Mineralization of Granitoid Rocks,China Geological Survey,Wuhan,Hubei 430205,China;Brigade 291,Guangdong Provincial Nuclear Industry Geological Bureau,Guangzhou,Guangdong 510800,China;Research Institute No.290,CNNC,Shaoguan,Guangdong 512029,China)
出处
《铀矿地质》
CAS
CSCD
2024年第6期1118-1131,共14页
Uranium Geology
基金
中国核工业地质局铀矿地质勘查项目(编号:202138-3)和中国地质调查局花岗岩成岩成矿地质研究中心开放基金课题(编号:PMGR202114)联合资助。
关键词
禾洞岩体
高分异I型花岗岩
地球化学
岩石成因
产铀潜力
广东省连山县
Hedong pluton
highly fractionated I-type granites
geochemistry
petrogenesis
uranium production potential
Lianshan of Guangdong Province
