新疆西昆仑大红柳滩矿集区含锂伟晶岩脉识别与找矿预测

Identification and prediction of lithium bearing pegmatite dikes in Dahongliutan ore concentration area in West Kunlun, Xinjiang

锂矿是新兴战略矿产资源。位于西昆仑造山带的大红柳滩地区是近几年中国新发现的又一世界级规模的锂多金属矿集区。矿集区自然条件差,常规的技术方法难以开展有效的伟晶岩脉识别,一定程度上影响了区域进一步找矿预测工作。文章在进行典型岩矿波谱实测分析的基础上,利用资源一号02D卫星(ZY1E)高光谱数据和高分二号(GF-2)高空间分辨率数据,识别有一定规模的伟晶岩脉;采用端员波谱法对ZY1E数据的矿物信息进行了提取,获取锂辉石、钠长石、白云母的端员波谱及空间分布范围,圈定锂矿化异常区,并识别含锂伟晶岩脉。基于ArcGIS平台,将锂矿化异常区与该矿集区内已知矿点叠加分析,发现矿化异常区范围与已知含锂伟晶岩脉矿点分布范围基本一致,以此为依据预测了一个新的找矿靶区,该方法可以作为类似高海拔、浅覆盖区开展伟晶岩型锂矿找矿预测有效的技术方法。

Lithium is an emerging strategic mineral resource. Located in the West Kunlun orogenic belt, the Dahongliutan area is another world-scale lithium polymetallic ore concentration area newly discovered in China in recent years. Lithium-bearing pegmatite are mainly developed near the contact zones between the Late Triassic acidic intrusions and the Triassic Bayankalashan Group meta-sedimentary rocks, accompanied by albite, with obvious mineral zoning. Due to the harsh natural environment in the ore concentration area, it is difficult to carry out effective identification on the pegmatite dykes by conventional technical methods, which affects the further prospecting and prediction work in the region to a certain extent. Based on the actual measurement and analysis of typical rock and mineral spectrum, this paper uses ZY1E hyperspectral data and GF-2 high spatial resolution data to establish the identification signatures of pegmatite dykes by RGB combination method;endmember spectroscopy is used to extract minerals from ZY1E data. To obtain the endmember spectrum and spatial distribution range of spodumene, albite and muscovite, so as to delineate the anomalous area of lithium mineralization and identify the ore-bearing pegmatite veins. Based on the ArcGIS platform, the anomalous lithium mineralization area and the known ore occurrences in the ore concentration area are superimposed and analyzed, and it is found that the range of the anomalous lithium mineralization area is basically the same as the distribution scope of the known ore-bearing pegmatite veins. A new prospecting target area is predicted, this method can be used as an effective technical method for prospecting and prediction of pegmatite-type lithium deposits in similar high-altitude and shallow coverage areas.