南岭地区双园冲锡矿成岩成矿时代及其对柿竹园-荷花坪地区锡钨找矿的指示  

Geochronology of granite and associated Sn mineralization in the Shuangyuanchong Sn deposit and its implication for Sn-W prospecting potential in the Shizhuyuan-Hehuaping area,the Nanling region,South China

作　　者：黄层 袁顺达 赵盼捞 HUANG Ceng;YUAN ShunDa;ZHAO PanLao(School of Earth Science and Mineral Resources,China University of Geosciences,Beijing 100083,China)

机构地区：[1]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《岩石学报》2023年第6期1717-1729,共13页Acta Petrologica Sinica

基　　金：国家自然科学基金项目(42272092、92062218、42203042);中国博士后科学基金项目(2022M712969)联合资助。

摘　　要：南岭成矿带是全球最重要的钨锡成矿带之一,区内钨锡成矿条件优渥,是开展钨锡找矿勘查的重要目标区。然而如何开展钨锡找矿工作,尤其是在已有矿床周缘圈定成矿远景区,是钨锡成矿作用研究以及找矿勘查工作关注的重要科学问题。双园冲矿床位于南岭成矿带中西段,处于荷花坪与柿竹园两个大型锡钨多金属矿田中间,并与两个矿田处于同一构造体系,但目前对该矿床的研究程度较低,由此也制约了其矿床成因研究及该区的找矿部署。本次研究获得双园冲云英岩化花岗岩的锆石和独居石原位LA-ICP-MS U-Pb年龄分别为161.2±2.5Ma和157.1±1.8Ma,与云英岩型矿石中锡石原位LA-ICP-MS U-Pb年龄(158.9±2.9Ma)一致,二者均形成于晚侏罗世,表明其具有密切的成因关系,这一年龄也与南岭成矿带钨锡成矿大爆发时代(150-160Ma)一致。综合对比双园冲锡矿及与其空间相邻的柿竹园和荷花坪锡多金属矿田特征显示,三者成岩成矿时代一致,岩体侵位和矿体分布均受NE向断裂控制,矿体也均赋存于中-上泥盆统碳酸盐岩地层中,并且成矿花岗岩具有相似的岩石学特征和岩浆源区。综合以上信息,本文提出三个矿床可能形成于同一次岩浆热液活动,成矿岩体可能来自地壳深部同一个大岩浆房,柿竹园和荷花坪之间的区域具有发育晚侏罗世花岗岩体及相关钨锡矿的较大潜力。根据双园冲锡矿及其周缘大型锡钨矿床浅部脉状Pb-Zn-Fe-Mn矿化和深部矽卡岩-云英岩型Sn-W矿化的特征,提出研究区乃至整个南岭地区浅部脉状Pb-Zn-Fe-Mn矿化是深部Sn-W找矿勘查的有利部位。The Nanling region of South China is one of the largest W-Sn provinces in the world and has long been the target area for W-Sn ore prospecting and exploration.However,how to carry out the W-Sn ore prospecting work in this area,especially around the existing deposits,is an important issue.The Shuangyuanchong Sn deposit,located in the west-central part of Nanling region,is in the middle region of the large Sn polymetallic orefields of Hehuaping and Shizhuyuan.Although these Sn polymetallic ore deposits are controlled by the same tectonic system,little is known about the formation of the Shuangyuanchong Sn deposit and its relationship with the surrounding Sn deposits,which seriously hinder the research and exploration of Sn deposits in the area.In this paper,we obtained in situ LA-ICP-MS U-Pb ages of zircon(161.2±2.5Ma)and monazite(157.1±1.8Ma)of greisenized granite as well as cassiterite U-Pb age(158.9±2.9Ma)of the greisen-type ore of the Shuangyuanchong Sn deposit,indicating that they have a close genetic relationship since they are all formed in the Late Jurassic,which is also consistent with the W-Sn mineralization explosion era(150~160Ma)in the Nanling region,South China.A comprehensive comparison between the Shuangyuanchong Sn deposit and the surrounding Shizhuyuan and Hehuaping Sn polymetallic orefields shows that the formation ages of the Sn deposit and associated granite of the three deposits are similar.Furthermore,the emplacement of granitic pluton and the distribution of ore bodies are all controlled by NE-trending faults,where the ore bodies all occur in the carbonate strata of the Upper-Middle Devonian,and the ore-related granites have similar petrological characteristics and magma source.Therefore,we conclude that these three deposits are formed in a single magmatic hydrothermal activity,and the ore-related granites come from the same deep magma chamber.The middle area of the Shizhuyuan-Hehuaping has great potential for the exploration of the Late Jurassic granitic pluton and related W-Sn deposits.

关 键 词：双园冲锡矿 南邻钨锡成矿带 锡石U-Pb年龄 找矿潜力 钨锡矿床 

分 类 号：P618.44[天文地球—矿床学] P618.67[天文地球—地质学]