四川道孚容须卡南锂矿床地质特征及找矿标志

Geological characteristics and prospecting criteria of the south Rongxuka lithium deposit in Daofu,Sichuan Province

容须卡南锂矿床位于松潘—甘孜—甜水海造山带东南缘,鲜水河断裂的西侧,雅江穹状变质体群内,属川西甲基卡—容须卡锂多金属矿重点规划工作区,由于交通、通信及自然条件较差,以往找矿工作一直未取得实质性进展。2013—2021年,四川省地质勘查基金、四川省地质矿产勘查开发局科技计划基金投入开展了普查找矿及科研工作,采用地质填图、土壤地球化学、岩石地球化学、视电阻率中梯、瞬变电磁测深、激电测深、地面高精度磁法、音频大地电磁测深、钻探、槽探、坑探及分析测试等综合方法手段,探获中型锂矿床1处,实现了找矿突破。本文通过对容须卡南锂矿床成矿地质背景、矿床地质特征、矿体地质特征进行系统研究,初步分析了矿床成因,总结出地质、生物、人工及地球物理异常4大类找矿标志,指出伟晶岩脉原生露头和转石、原始结晶分异带、正向微地形为直接找矿标志;变质带及近矿围岩蚀变、原生晕及次生晕异常、视电阻率、磁化率异常、杜鹃植物元素含量变化、前人留下的勘查遗迹和带有指向性的特殊地名为间接找矿标志,研究成果对雅江穹隆群乃至松潘—甘孜—甜水海造山带花岗伟晶岩型锂多金属矿找矿工作具有重要的现实指导意义。

The south Rongxuka lithium deposit is located in the southeastern margin of the Songpan-Ganzi-Tianshuihai orogen,the west side of the Xianshuihe fault,and the Yajiang dome metamorphic body group.It belongs to the key planning work area of the Jiajika-Rongxuka lithium polymetallic prospeeting in western Sichuan Province.Due to poor traffic,communication and natural conditions,the previous prospecting work has not made substantial progress.From 2013 to 2021,the Geological Exploration Fund of Sichuan Province and the Science and Technology Plan Fund of the Geological and Mineral Bureau of Sichuan Province had invested in a new round of surrer and mineral exploration work,prospecting and scientific research work.A medium-sized lithium deposit has been discovered by means of comprehensive methods such as geological mapping,soil geochemistry,rock geochemistry,intermediate gradient of apparent resistivity,transient electromagnetic sounding,induced polarization sounding,ground high-precision magnetic method,audio magnetotelluric sounding,drilling,trenching,pit exploration and analysis testing,and a breakthrough in prospecting has been achieved.In this paper,through the systematic study of the metallogenic geological background,geological characteristics of the deposit and geological characteristics of the ore body of the Rongxukanan lithium deposit,the genesis of the deposit is preliminarily analyzed,and four types of prospecting indicators of geological,biological,artificial and geophysical anomalies are summarized.It is pointed out that the primary outcrop and rotary stone of the pegmatite vein,the original crystallization differentiation zone and the positive microtopography are the direct prospecting indicators;the indirect prospecting indicators include wall rock alteration,primary halo and secondary halo anomaly,apparent resistivity,magnetic susceptibility anomaly,content change of rhododendron plant elements,exploration relics left by predecessors and special place names with directivity,which have important practical guiding significance for prospecting work of granitic pegmatite type lithium polymetallic deposit in Yajiang dome metamorphic group and Songpan-Ganzi-Tianshuihai orogen.