投稿时间：2021-11-26
修订日期：2022-07-10
网络发布日期：2022-09-09
中文摘要:广西镇龙山地区发育大量脉状铅、锌、银多金属矿体，同时出露多个花岗斑岩和石英斑岩岩体，岩体和矿体受近东西向羊角山-长帽岭断裂控制。为研究岩体与矿体的关系，文章在详实野外地质工作的基础上，对研究区典型的岩体开展了岩石学、地球化学及锆石年代学研究。主量、微量元素组成显示，知府山花岗斑岩的w(SiO2)为63.59%~68.78%，w(K2O)为4.5%~5.68%，w(MgO)为1.07%~1.77%；长帽岭花岗斑岩的w(SiO2)为66.67%~69.75%，w(MgO)为0.71%~2%，w(K2O)为1.54%~3.91%。2个岩体均具有高硅、富钾、低镁的特征，A/CNK>1.1，均显示过铝质岩石特征。2个岩体均富集Rb、K、Ba、Th、U等大离子亲石元素，而亏损Nb、Sr、P、Ti等高场强元素，稀土元素总量（∑REE）平均值为187.94×10-6，稀土元素配分模式呈轻稀土元素相对富集的右倾型，明显的Eu负异常。岩石地球化学特征及岩相学特征显示，该区花岗斑岩为高钾钙碱性过铝质S型花岗岩，岩体经历了较高程度的结晶分异。锆石U-Pb年龄结果显示，知府山、长帽岭花岗斑岩、洗马塘石英斑岩成岩年龄为92~95 Ma，形成于碰撞后伸展环境。成岩物质主要来自于上地壳物质的部分熔融，并有少量幔源物质加入。镇龙山地区多金属矿床在平面上围绕岩体显示高温到低温的矿化分带现象，成岩成矿时代在时间上具有一致性，表明岩浆活动与成矿作用之间存在成因联系，说明区内脉状铅锌银矿床属于岩浆热液矿床。晚白垩世岩浆热液成矿事件是华南地区燕山晚期成岩成矿事件的一部分，其构造背景与华南在晚白垩世受太平洋板块俯冲影响所致。
Abstract:A large number of vein lead, zinc and silver polymetallic ore bodies are developed in Zhenlongshan area, Guangxi. At the same time, many granite porphyry and quartz porphyry rock bodies are exposed. The rocks and ore bodies are controlled by the near East-West Yangjiaoshan-Changmaoling fault. Based on the detailed field geological work, the petrological, geochemical and zircon geochronological characteristics of typical intrusive plutons in the region are studied. The composition of major and trace elements shows that the SiO2 content of Zhifushan granite porphyry is 63.59%~68.78%, w(K2O) is 4.5%~5.68%, and w(MgO) is 1.07%~1.77%; the SiO2 content of Changmaoling granite porphyry is 66.67%~69.75%, w(MgO) is 0.71%~2%, and w(K2O) is 1.54%~3.91%. The two rocks are characterized by high silicon, rich potassium and low magnesium, with A/CNK>1.1, showing the characteristics of peraluminous rocks. Both rocks are rich in Rb, K, Ba, Th, U and other large ion lithophile elements, while they are deficient in Nb, Sr, P, Ti and other high field strength elements. The average value of the total amount of rare earth elements (ΣREE) is 187.94×10-6. The rare earth distribution model shows that the light rare earth is relatively enriched in the right dip type, with obvious Eu negative anomaly. The geochemical and petrographic characteristics show that the granite porphyry in this area is high potassium calc alkaline peraluminous S-type granite, and the rock mass has experienced a high degree of crystallization differentiation. Zircon U-Pb dating results show that the diagenetic ages of Zhifushan granite porphyry, Changmaoling granite porphyry and Ximatang quartz porphyry are 92~95 Ma, which are formed in the post-collision extensional environment. The diagenetic materials are mainly derived from the partial melting of the upper crust material, and a small amount of mantle-derived materials are added. The polymetallic deposits in Zhenlongshan area show the mineralization zoning from high temperature to low temperature around the rock mass on the plane. The diagenetic and metallogenic epochs are consistent in time, indicating that there is a genetic connection between magmatic activity and mineralization. The deposits in this area are magmatic hydrothermal deposits. Late Cretaceous magmatic hydrothermal metallogenic event is a part of Late Yanshanian magmatic metallogenic event in South China, caused by the subduction of Pacific plate in Late Cretaceous.
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基金项目:本文得到国家重点基础研究发展计划(973 计划)课题"改造型花岗岩钨锡稀有金属成矿作用"(编号:2012CB416704)、广西壮族自治区部门前期地质勘查项目"广西大瑶山地区多期次岩浆活动及成矿作用研究"(编号:桂地矿地[2014]17 号)、西部矿产资源与地质工程教育部重点实验室(长安大学)开放基金(编号:300102268501)和云南省地球系统科学重点实验室开放课题(编号:ESS2021004)联合资助
引用文本：
王昱,孔志岗,陈懋弘,陈港,李杨林.2022.广西镇龙山地区花岗斑岩岩石地球化学及年代学研究[J].矿床地质,41(4):789~805WANG Yu,KONG ZhiGang,CHEN MaoHong,CHEN Gang,and LI YangLin.2022.Study on geochemistry and chronology of granite porphyry in Zhenlongshan area, Guangxi[J].Mineral Deposits41(4):789~805
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