藏南中新世钾质-超钾质火山岩中的锂赋存状态研究:对青藏高原盐湖锂成因的指示  

Lithium occurrence state in Miocene potassic-ultrapotassic volcanic rocks in southern Tibet:An indication for the genesis of lithium in Tibetan salt lakes.

作　　者：姜茗瀚 王瑞[1] 田祥雨 JIANG MingHan;WANG Rui;TIAN XiangYu(State Key Laboratory of Geological Processes and Mineral Resources,China University of Geosciences(Beijing),Beijing 100083,China)

机构地区：[1]中国地质大学(北京)地质过程与成矿预测全国重点实验室,北京100083

出　　处：《岩石学报》2025年第3期922-937,共16页Acta Petrologica Sinica

基　　金：国家自然科学基金重大计划培育项目(92162104)资助.

摘　　要：锂是支撑战略新兴产业发展的重要矿产资源,其需求量急剧增加。本文通过全岩主微量元素、电子探针和激光微区分析发现藏南中新世钾质-超钾质火山岩中含有一定量锂元素,全岩锂含量为11.2×10^(-6)~74.1×10^(-6),平均值为31.7±41.4×10^(-6);本文钾质-超钾质煌斑岩分析结果中,锂的含量普遍高于上地壳平均值,其中甲村地区煌斑岩中的锂含量最高可达74.1×10^(-6)。在钾镁煌斑岩和少量斜长白榴岩中金云母是主要造岩矿物。锂元素主要赋存在金云母中,含量最高可达596.6×10^(-6)(平均值为337.1±407.3×10^(-6))。此外,藏南中新世钾质-超钾质火山岩在空间分布上与拉萨地体的富锂热泉有相似性,都产出于拉萨地体的裂谷带中,时代从老到新全岩锂含量呈现增长趋势。青藏地区盐湖锂提供锂源的热泉可能源于富含锂元素的岩浆热液流体,这些钾质-超钾质岩浆去气和地下水混合,经过裂谷系统输送到热泉。热泉补给盐湖,盐湖经过蒸发浓缩成为盐湖锂矿。本文初步认为藏南中新世钾质-超钾质火山岩为青藏盐湖锂矿提供了潜在的锂物质来源。Lithium is an important mineral resource supporting the development of strategic emerging industries,and its demand has increased sharply.This study,through whole-rock major and trace element analysis,electron probe microanalysis,and laser microarea analysis,has identified the presence of lithium in Miocene potassic-ultrapotassic volcanic rocks in southern Tibet.The whole-rock lithium content ranges from 11.2×10^(-6) to 74.1×10^(-6),with an average value of 31.7±41.4×10^(-6).The test results of potassic-ultrapotassic lamprophyres in this study show that the lithium content is generally higher than the average value of the upper crust.Among them,the lithium content in the lamprophyres from the Jiacun area reaches up to 74.1×10^(-6).In K-Mg-lamprophyre and a small amount of plagioclase leucite,phlogopite is the main rock-forming mineral.Lithium is mainly found in phlogopite,with a maximum content of 596.6×10^(-6)(average 337.1±407.3×10^(-6)).In addition,the potassic-ultrapotassic volcanic rocks in southern Tibet are similar in spatial distribution to the Li-rich geothermal water in the Lhasa terrane,both of which are produced in the rift zone of the Lhasa terrane,and the lithium content in the whole rocks shows an increasing trend from old to new.The geothermal water that provides lithium source for salt lake lithium in Qinghai-Tibet region may be derived from lithium-rich magmatic hydrothermal fluid,which is degassed by potassic-ultrapotassic magma mixed with groundwater and transported to the geothermal water through the rift system.Geothermal water recharge salt lake,salt lake through evaporation concentrated into salt lake lithium ore.This study preliminarily suggests that the Miocene potassic-ultrapotassic volcanic rocks in southern Tibet may have provided a potential lithium source for the salt lake lithium deposits on the Tibetan Plateau.

关 键 词：钾质-超钾质火山岩 锂元素 微区分析 地球化学 

分 类 号：P588.14[天文地球—岩石学] P595[天文地球—地质学] P618.71