希夏邦马峰地区矽卡岩型稀有金属矿化:岩石学特征、成矿时代及其地质意义  

Skarn-type rare metal mineralization in the Mount Shisha Pangma region:Petrological characteristics,mineralization age and its geological significance

作　　者：侯康师 王佳敏[1] 胡方泱 杨雷 HOU KangShi;WANG JiaMin;HU FangYang;YANG Lei(State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;College of Earth Sciences,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]岩石圈演化国家重点实验室,中国科学院地质与地球物理研究所,北京100029 [2]中国科学院大学地球与行星科学学院,北京100049 [3]中国科学院矿产资源研究重点实验室,中国科学院地质与地球物理研究所,北京100029 [4]成都理工大学地球科学学院,成都610059

出　　处：《岩石学报》2024年第5期1527-1547,共21页Acta Petrologica Sinica

基　　金：国家重点研发计划项目(2022YFF0800800);第二次青藏高原综合科学考察研究项目(2019QZKK0703、2022QZKK0203);国家自然科学基金项目(42488201);中国科学院青年创新促进会项目(2022065)联合资助.

摘　　要：近年来,喜马拉雅稀有金属找矿工作和成矿研究不断取得突破,喜马拉雅已成为我国新的战略性矿产资源基地。本次研究对希夏邦马峰地区的吉隆岩体北部扎龙沟、岗布以及聂拉木北部等多处的矽卡岩进行了岩相学、矿物学和年代学研究,指出该区域广泛发育石榴子石、透辉石、符山石、绿帘石和角闪石等典型矽卡岩矿物。研究结果显示,扎龙沟矽卡岩具有明显的Li-Be-Sn矿化现象,成矿元素主要赋存在符山石(Li:469×10^(-6)~3162×10^(-6);Be:47.9×10^(-6)~2010×10^(-6);Sn:58.1×10^(-6)~1767×10^(-6))和云母(Li:2900×10^(-6)~3570×10^(-6))中,且云母中Rb(1572×10^(-6)~2364×10^(-6))、Cs(390×10^(-6)~749×10^(-6))、Ga(68.2×10^(-6)~111×10^(-6))元素含量较高;岗布矽卡岩以Li-Be矿化为主,赋存矿物为符山石(Li:833×10^(-6)~1624×10^(-6);Be:401×10^(-6)~1664×10^(-6);Sn:87.8×10^(-6)~181×10^(-6))和榍石(Sn:30340×10^(-6)~48600×10^(-6));聂拉木矽卡岩以Sn矿化为主,赋存矿物为石榴子石(92.3×10^(-6)~571×10^(-6))和绿帘石(86.0×10^(-6)~2003×10^(-6))。榍石U-Pb定年结果显示,扎龙沟矽卡岩形成于19~18Ma,岗布和聂拉木矽卡岩形成于24~23Ma,分别与已报道的钠长石花岗岩、电气石白云母淡色花岗岩时代一致,是岩浆出溶的热液流体交代围岩的产物,反映喜马拉雅稀有金属阶段性成矿特点。榍石Zr和黑云母Ti等温度计结果结合矿物成分表明,矽卡岩化过程中,热液流体温度从~680℃降低至~520℃,晚期均以氧化环境为主。进变质过程中脱CO 2导致原岩孔隙度增加,为后续成矿流体的加入和热量传输提供通道;退化蚀变过程中体积增大,岩石产生构造裂隙,控制成矿矽卡岩最终产出形态。综合研究表明,淡色花岗岩在藏南拆离系驱动下高度分异演化造成Li、Be、Sn等元素富集,晚期出溶的热液流体与碳酸盐岩围岩发生接触交代变质和矽卡岩化反应,是吉隆-聂拉木一带矽卡岩�In recent years,breakthroughs have been made in prospecting and researching Himalayan rare metals,making the Himalaya a new strategic mineral resource base in China.This study studied the petrography,mineralogy and chronology of skarn in the Tsalung and Gangbu districts in the northern of Gyirong pluton and Nyalam district,Mount Shisha Pangma region and pointed out that skarns are mainly composed of garnet,diopside,vesuvianite,epidote and amphibolite.The Tsalung skarn had apparent Li-Be-Sn mineralization,and the ore-forming elements mainly existed in vesuvianite(Li:469×10^(-6)~3162×10^(-6);Be:47.9×10^(-6)~2010×10^(-6);Sn:58.1×10^(-6)~1767×10^(-6))and mica(Li:2900×10^(-6)~3570×10^(-6))with the high contents of Rb(1572×10^(-6)~2364×10^(-6)),Cs(390×10^(-6)~749×10^(-6))and Ga(68.2×10^(-6)~111×10^(-6)).The Gangbu skarn was also dominated by Li-Be mineralization,and the Li-Be-Sn bearing minerals were vesuvianite(Li:833×10^(-6)~1624×10^(-6);Be:401×10^(-6)~1664×10^(-6);Sn:87.8×10^(-6)~181×10^(-6))and titanite(Sn:30340×10^(-6)~48600×10^(-6)).Sn mineralization also occurred in Nyalam skarn,and the Sn-bearing minerals were garnet(92.3×10^(-6)~571×10^(-6))and epidote(86.0×10^(-6)~2003×10^(-6)).The Tsalung skarn was formed at 19~18Ma,and Gangbu and Nyalam skarn was formed at 24~23Ma,which was consistent with the reported ages of albite granite and tourmaline muscovite granite and was the product of the reaction between the hydrothermal fluid that dissolved from the evolved granitic melt and the Ca-rich country rock,reflecting the characteristics of periodic mineralization of Himalayan rare metals.Hydrothermal fluid temperature decreased from~680℃to~520℃,and the late stage was an oxidation environment.The increase of porosity caused by decarbonization and CO 2 release provided a channel for subsequent ore-forming fluid addition and heat transfer.Tectonic fissures controlled the attitude of ore-forming skarn.The high degree of magma differentiation enriched Li,Be,Sn in the melt,and the contact meta

关 键 词：喜马拉雅 矽卡岩 稀有金属成矿 接触交代变质 热液流体 

分 类 号：P588.312[天文地球—岩石学] P597.3[天文地球—地质学] P618.6