新疆白杨河铀铍矿区航空高光谱矿物填图及蚀变特征分析

Mineral mapping and analysis of alteration characteristics using airborne hyperspectral remote sensing data in the Baiyanghe uranium and beryllium ore district,Xinjiang

以新疆白杨河铀铍矿区为研究区,通过建立航空高光谱数据CASI/SASI矿物填图处理流程,运用混合调制匹配滤波技术实现了多种蚀变矿物的填图。填图结果的野外验证表明,3种绢云母亚类的准确性高于85%,其他各类矿物的准确性高于90%。叠加研究区铀矿点资料,发现白杨河矿区赤铁矿化和高铝绢云母的空间分布特征与铀矿点分布高度相关,主要位于杨庄岩体与外围火山岩的北接触带附近,呈明显分带性。并且,高、中、低铝绢云母的空间分布指示矿床北部和南部的热液活动温度可能存在差异,区域上存在多期热液活动作用。这为矿区外围找矿预测和区域地质成因研究提供了参考和依据。

The technology of hyperspectral remote sensing has the special advantages in regional alteration information extraction. Hyperspectral mineral mapping has important reference value for hydrothermal uranium exploration. In this paper, the data processing flow of CASI/SASI airborne hyperspectral remote sensing data was established and mixture tuned matched filtering was applied to realize minerals mapping in the Baiyanghe uranium and beryllium ore district, Xinjiang. The results of mineral mapping were evaluated by the field verification and the results show that the accuracy of three kinds of sericite’s mapping is higher than 85% and the accuracy of other minerals’ mapping is larger than 90%. The overlay analysis of uranium ore spots and the results of mineral mapping show that there is a significantly correlation of the characterization of spatial distribution between uranium ore spots and the alteration of hematite and Al-rich sericite. The alterations of hematite and Al-rich sericite are near the contact zone between Yangzhuang rock body and peripheral volcanic rocks and exhibit distinct characteristics of zoning. Furthermore, there may be some differences in the temperature of hydrothermal activity between the north and the south of the deposit according to the spatial distribution characteristics of three kinds of sericite, which indicates the existence of multiple hydrothermal activities in the region. The results obtained by the authors can provide references for prospecting prediction of the periphery of the ore district and regional geological genesis research.