青海柴北缘地区茶卡北山锂铍稀有金属伟晶岩型矿床垂向分带特征  

Vertical zonation characteristics of Chakabeishan Li-Be rare-metal pegmatite deposit in northern margin of Qaidam Basin,Qinghai Province

作　　者：刘承先[1] 孙丰月[1] 钱烨[1] 吴东倩[1] 惠潮 卢寅花 LIU Chengxian;SUN Fengyue;QIAN Ye;WU Dongqian;HUI Chao;LU Yinhua(College of Earth Sciences,Jilin University,Changchun 130061,China)

机构地区：[1]吉林大学地球科学学院,长春130061

出　　处：《世界地质》2021年第4期847-859,880,共14页World Geology

基　　金：中国地质调查局项目(12120114080901)。

摘　　要：茶卡北山锂铍伟晶岩型矿床是近年发现的一处中型锂铍稀有金属矿床,呈现垂向分带特征。通过研究伟晶岩脉岩相学、矿化特征,并结合电子探针测试,探讨伟晶岩垂向分带及矿床成因。茶卡北山伟晶岩根据岩相学特征分为二云母伟晶岩,文象结构伟晶岩,条带状构造伟晶岩,含绿柱石伟晶岩,含绿柱石、锂辉石伟晶岩和含锂辉石伟晶岩6个垂向分带;根据矿化特征分为无矿化带、Be矿化带、Li-Be矿化带和Li矿化带4个垂向分带。白云母电子探针测试结果显示矿化程度随伟晶岩演化程度的加强而不断增强。茶卡北山伟晶岩矿床经由结晶分异作用、熔体-流体不相容作用及流体交代作用共同作用于一期形成。The Chakabeishan Li-Be pegmatite deposit,a medium-sized Li-Be rare metal deposit,was discovered in recent years,emerged as vertical zonation characteristics.By studying the petrography and mineralization features of the pegmatite dikes,and combined with the EPMA experiment,the origin of the pegmatite vertical zoning and the ore genesis of the deposit have been discussed.The Chakabeishan pegmatite dikes could be differentiated into 6 vertical zonings by the petrography characteristics such as two-mica pegmatite,graphic texture pegmatite,banded structure pegmatite,beryl bearing pegmatite,beryl-spodumene bearing pegmatite and spodumene bearing pegmatite;into 4 vertical zonings according to the mineralization characteristics such as ore free zoning,Be mineralization zoning,Li-Be mineralization zoning and Li mineralization zoning.With the EPMA analysis of the muscovite in pegmatite veins,it is showed that the mineralization degree increased with the strengthening of pegmatite evolution.The Chakabeishan pegmatite deposit is formed by crystallization differentiation,melt-fluid immiscibility and fluid metasomatism together in one period.The cognition of the vertical zonings of the pegmatite could be contributed to refine the progress of the evolution of pegmatite magma system,and play an important role for prospecting and exploration.

关 键 词：柴北缘 茶卡北山 伟晶岩 分带特征 白云母 成矿规律 

分 类 号：P618.6[天文地球—矿床学]