喜马拉雅东段错那洞钨-锡-铍矿床中铍的赋存状态及成因机制初探  

Preliminary study on occurrence status of beryllium and genetic mechanism in Cuonadong tungsten-tin-beryllium deposit,eastern Himalaya

作　　者：何畅通 秦克章[1,2,3] 李金祥 周起凤 赵俊兴[1,2,3] 李光明 HE ChangTong;QIN KeZhang;LI JinXiang;ZHOU QiFeng;ZHAO JunXing;LI GuangMing(Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Innovation Academy for Earth Science,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 Continental Collision and Plateau Uplift,Institute of Tibetan Plateau Research,Chinese Academy of Sciences,Beijing 100101,China;Institute of Mineral Resources Research,China Metallurgical Geology Bureau,Beijing 101300,China)

机构地区：[1]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 [2]中国科学院地球科学研究院,北京100029 [3]中国科学院大学地球与行星科学学院,北京100049 [4]中国科学院青藏高原研究所大陆碰撞与高原隆升重点实验室,北京100101 [5]中国冶金地质总局矿产资源研究院,北京101300

出　　处：《岩石学报》2020年第12期3593-3606,I0001-I0015,共29页Acta Petrologica Sinica

基　　金：第二次青藏高原科学考察专题(2019QZKK0806、2019QZK0803);中国科学院地质与地球物理研究所重点部署项目(IGGCAS-201902)联合资助。

摘　　要：近年来喜马拉雅淡色花岗岩带被认为是稀有金属成矿的有利地区,并已在该区伟晶岩中发现诸多稀有金属矿物。错那洞矿床是该带内发现最早并具有较大规模的钨锡铍(W-Sn-Be)矿床,Be矿化包括伟晶岩型和矽卡岩型,但目前铍元素的赋存状态还没有被清晰地查明。伟晶岩型矿化主要为伟晶岩中晶型较好的绿柱石晶体;而矽卡岩型铍矿化表现形式则复杂多样。Be元素除了赋存于绿柱石、硅铍石、羟硅铍石等含铍矿物中,还可以广泛分布于矽卡岩矿物中。其中,符山石(Be含量:43×10-6~887×10-6)和方柱石(Be含量:1333×10-6~4643×10-6)是铍元素赋存的主要载体。矽卡岩型矿化与淡色花岗岩有关,岩浆高分异演化使熔体中Be、Sn、W及挥发分逐步富集,在伟晶岩中饱和绿柱石;之后Be元素在F的络合下随出溶流体进入碳酸盐岩,发生水岩相互作用,萤石的析出引起Be-F络合物失稳,导致Be元素的沉淀。含铍矿物种类及成因机制的研究将有助于指导喜马拉雅地区同类型矿化的评价。In recent years,the Himalayan leucogranite belt is considered as a favorable area for rare-metal mineralization,and many rare metal minerals have been found in this area.The Cuonadong deposit is the first newly discovered giant W-Sn-Be deposit in this belt.The beryllium mineralization includes pegmatite-type and skarn-type,but the occurrence state of beryllium element in this deposit is still unclear.Pegmatite-type mineralization is represented by beryl with better crystals,while skarn-type Be mineralization has various manifestations.The Be element not only occurs in beryllium-containing minerals such as beryl,phenacite and bertrandite,but also can be widely distributed in some skarn minerals.Among them,the contents of Be in vesuvianite and scapolite vary within 43×10-6~887×10-6 and 1333×10-6~4643×10-6,respectively.The genesis of skarn mineralization is related to the emplacement of leucogranites.The high degree of magma differentiation gradually enriches Be,Sn,W and volatiles in the melt,and saturates the beryl in the pegmatite;then the Be element is complexed by F within the fluid released from the magma and enters the carbonate.The fluid interacts with the carbonate,and the precipitation of fluorite causes the instability of the Be-F complex,leading to the precipitation of the Be element.The study on the occurrence state and mineralization mechanism of Be element in Cuonadong deposit is helpful to guide the exploration of the similar type of deposits in the Himalayas.

关 键 词：错那洞 花岗伟晶岩 矽卡岩 铍赋存状态 符山石 方柱石 成因机制 喜马拉雅 

分 类 号：P618.72[天文地球—矿床学]