川西甲基卡伟晶岩型锂矿矿床地质特征及成矿机制研究

Geological Characteristics and Metallogenic Mechanism Analysis of the Jiajika-type Lithium Deposit,Western Sichuan

甲基卡花岗伟晶岩型锂矿床位于松潘-甘孜造山带东缘,在国际国内稀有金属需求大背景下,具有非常重要的战略意义。岩体和矿脉主要侵位于三叠系复理石沉积变质砂岩中,产生一系列的热液接触变质作用,根据矿床地质特征和矿脉产出特征等研究得出,印支造山晚期(稳定期),垂直地壳流动引发底辟作用造成岩浆上涌挤出,导致区域增温引起三叠系复理石沉积局部熔融,形成富Li富F的S型花岗岩浆。岩浆上侵减压发生液态不混溶分离出富挥发性、贫硅酸盐的熔体和贫挥发性、富硅酸盐的熔体,同时伴随着稀有金属元素的矿化,最终在变质盖层中形成透镜状-似层状的富Li伟晶岩脉。

The Jiajika granite pegmatite-type lithium deposit is located on the eastern edge of the Songpan-Ganze orogenic belt,and its proven reserves are among the highest in the world.The rock and veins are mainly invaded in the Triassic flysch sedimentary metamorphic sandstone,resulting in a series of hydrothermal contact metamorphisms.In the late Indo-Chinese orogenic period(stable period),according to the geological characteristics of ore deposits and the vein,it is concluded that vertical crustal flow triggered vertical diapir,which caused magma upwelling and extruding.leading to regional warming.Triassic flysch deposits melt locally,forming S-type granite magma rich in Li and F.Magma intrusion and decompression occur liquid immiscible separation of volatile and poor silicate melts and lean volatile and silicate rich melts.At the same time,it is accompanied by the mineralization of rare metal elements.Lenticular-like layered Li-rich pegmatite veins are formed in the layer.