锂的地球化学性质与富集机理  

The Geochemical Properties and Enrichment Mechanism of Lithium

作　　者：薛颖瑜 刘海洋 孙卫东[1,2,3,4] XUE Yingyu;LIU Haiyang;SUN Weidong(Center of Deep Sea Research,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,Shandong,China;Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266237,Shandong,China;Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao 266071,Shandong,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院海洋研究所,深海研究中心,山东青岛266071 [2]青岛海洋科学与技术试点国家实验室,海洋矿产资源评价与探测技术功能实验室,山东青岛266237 [3]中国科学院海洋大科学研究中心,山东青岛266071 [4]中国科学院大学,北京100049

出　　处：《大地构造与成矿学》2021年第6期1202-1215,共14页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(41903006);中国博士后科学基金项目(2019M652497);山东省博士后创新项目和青岛市博士后应用研究项目联合资助。

摘　　要：在地球化学性质上,锂表现为中度不相容元素的特征,因此在地壳中较为富集。由于锂易富集于流体中,在岩浆演化晚期,随着挥发分的增加,锂可以通过热液强烈富集,并形成伟晶岩型(花岗岩型)锂矿。在板块俯冲过程中,锂可以被多硅白云母、绿辉石等矿物带至深部。多硅白云母的分解释放出Li和F等助熔元素,可以诱发部分熔融,形成富锂岩浆岩。在地表风化过程中,锂易于进入水体,在封闭盆地内可以得到保存,进而形成大型的卤水型锂矿床。在碰撞带的腹地,岩浆岩通常富锂,而且由于造山带的阻隔,在背海面形成干旱气候区,这些干旱地区的盆地可以储存碰撞后岩浆岩风化的产物,进而形成卤水型锂矿床,因此板块俯冲是形成锂矿床的关键因素。我国华南地区存在大量的中生代高分异锂‒氟花岗岩,该类花岗岩具有高的Li含量(9×10^(−6)~5200×10^(−6))和高的Li/MgO值(13×10^(−4)~130000×10^(−4)),是卤水型锂矿的重要物源,因此该类花岗岩附近的中生代红层盆地是寻找大型卤水型锂矿床的重要靶区。作为新兴的示踪工具,Li同位素在硬岩型锂矿床中得到了初步应用,并表现出一定的示踪潜力。Since the beginning of the 21^(st) century,partly due to the public awareness of global warming,the research and development of new energy has been rapidly advanced.As a critical metal,lithium is widely used in electronic products and new energy vehicles,and plays an important role.Lithium is a moderately incompatible element,which is enriched in the continental crust.It is a fluid mobile element,and thus it may be highly enriched during hydrothermal activities especially at the late stage of magmatic evolution,forming pegmatite type lithium deposit.During plate subduction,the decomposition of phengite may induce partial melting and form lithium-rich magmatic rocks favorable for the formation of pegmatite type lithium deposit.Lithium is also mobile during weathering,forming large brine type lithium deposits in closed basins.In the hinterland of a collisional belt,magmatic rocks are usually rich in lithium.Meanwhile,arid climate zones are formed due to the barrier of orogenic belt.Basins in these arid areas can store the weathering products from magmatic rocks,promoting the formation of brine type lithium deposits.Therefore,plate subduction is the key factor to the formation of lithium deposits.There are a large number of Mesozoic highly differentiated lithium-fluorine enriched granites in South China,which have high Li contents(9×10^(−6) to 5200×10^(−6))and high Li/MgO ratios(13×10^(−4) to 130000×10^(−4)).Therefore,the Mesozoic basins in South China may be important target areas for exploration of large brine lithium deposits.It is worth pointing out that,as a new tracer,lithium isotopes have been preliminarily applied in exploration of pegmatite lithium deposits and showed some prospecting potential.

关 键 词：锂 地球化学 卤水型 花岗伟晶岩型 板块俯冲 Li同位素 

分 类 号：P595[天文地球—地球化学]