新疆喀喇昆仑大红柳滩一带锂矿光谱特征及其找矿指示意义

Spectral Characteristics and Prospecting Implications of Lithium Deposits in Dahongliutan Area,Karakoram,Xinjiang

近年来,新疆喀喇昆仑大红柳滩地区锂铍矿取得重大找矿发现,显示良好的成矿潜力。受其高寒深切割环境的制约,矿区外围的地质找矿工作推进不易。前人利用高分、多光谱遥感数据及高光谱技术在该区花岗伟晶岩型锂铍矿找矿工作中发挥出积极作用,发现了505、507、俘虏沟南1号、俘虏沟南2号等多处大型锂铍矿产地。笔者通过对区内花岗伟晶岩型锂矿床中岩、矿石开展地面光谱测试,系统对比不同岩性赋矿地层、岩体、含矿伟晶岩、不含矿伟晶岩的光谱特征。通过光谱解算剖析其矿物组合,分析显示含矿伟晶岩中含锂矿物以锂辉石、锂云母为主,少量锂绿泥石。含矿伟晶岩具高反射率,发育强Al-OH吸收峰,受其接触交代蚀变影响,发育Mg-OH吸收峰,二者共同构成区内含矿伟晶岩的标志性遥感异常组合。采用国产高光谱遥感卫星数据,利用匹配滤波方法提取上述异常组合,圈定找矿有利区7处,为该区下一步锂铍找矿工作提供了依据。

In recent years,mineral exploration of Lithium(Li)-Beryllium(Be)deposit in Dahongliutan area of Karakoram,Xinjiang,has been greatly improved and showed good metallogenic potential.However,because of the high cold and deep cutting environment,the mineral prospecting work in this area is hard whereas urgently needs to develop.Our group has played a positive role in the exploration of pegmatite type Li-Be deposit by using high-resolution,multi-spectral remote sensing data and hyperspectral technology in this area,and several large Li-Be deposits,such as 505,507,south fulugou 1and south fulugou 2have been discovered.In this study,we carried out the ground spectral testing of rock and ore deposits in pegmatite type lithium deposits in this area.The spectral characteristics of bearing ore stratum,rock mass,ore bearing pegmatite and ore without pegmatite of different lithology are systematically compared.The mineral assemblages are calculated and analyzed.It is considered that the lithium-bearing pegmatite in the ore bearing pegmatite is mainly composed of spodumene and lepidolite,and a small amount of lithium chlorite,with high reflectivity and shows strong Al-OH absorption peak.Mg-OH absorption peak is also developed under the influence of the later hydrothermal alteration,which together constitute the symbolic remote sensing anomaly assemblage of ore bearing pegmatite in the area.Basing on the domestic hyperspectral remote sensing satellite data,the above anomaly combinations were extracted by matching filtering method,and 7 prospecting targets were delineated,which is important for the further lithium beryllium prospecting in this area.