航空高光谱CASI-SASI数据蚀变矿物信息提取与应用 ——以甘肃省敦煌市小金窝子地区为例

航空高光谱遥感数据具有“空谱合一”的优势，深入挖掘并应用高光谱数据中蕴含的蚀变矿物地质信息具有重要意义。本文应用航空高光谱CASI-SASI数据，建立了基于“整体谱形-特征参量协同”的蚀变矿物信息提取流程，并在甘肃省敦煌市小金窝子地区开展了蚀变矿物信息提取、地质涵义分析和野外查证。基于高光谱CASI-SASI数据成功提取了褐铁矿、绿泥石、绿帘石、短波云母、中短波云母、中长波云母、长波云母共7种蚀变矿物。高光谱CASI-SASI数据提取的大面积区域性分布的蚀变矿物多为区域热液作用产物，小范围定向分布的蚀变矿物与断裂、岩脉等成矿热液活动关系密切，局部产出且具定向性的中短波云母与断裂构造及酸性脉体关系密切，基于野外地质调查和ASD光谱实测的蚀变矿物野外查证工作证实蚀变矿物提取结果可信。褐铁矿+中短波云母的蚀变矿物组合具有金矿化指示意义，为基础地质调查和矿产资源勘查提供了重要的遥感信息。

Extraction of alteration minerals based on the airborne hyperspectral CASI-SASI data and the application to the Xiaojinwozi area in Dunhuang City, Gansu Province

Airborne hyperspectral remote sensing data are well featured by their integrated spatial and spectral resolution, and a full use of these data to extract alteration minerals will be of great significance in geological field. Based on the airborne hyperspectral CASI-SASI data, this work established a technical workflow for the extraction of alteration minerals on the basis of whole spectral shape synergy with characteristic parameters. Taken the Xiaowozi area in Dunhuang City of Gansu Province as an example, the extraction of alteration minerals, geological analysis and field verification were conducted. Seven types of alteration minerals were extracted using the hyperspectralCASI-SASI data, i.e., limonite, chlorite, epidote, short-wave sericite, medium- to short-wave sericite, medium- to long-wave sericite and long-wave sericite. The regionally distributed alteration minerals are often the products of regional hydrothermal activities, and the small-scale directionally distributed alteration minerals are closely related to the ore-forming hydrothermal activities such as faults and dykes. The locally directionally distributed medium- to short-wave sericites are closely related to the fault structure and acid veins. Field geological investigations and ASD spectral measurements have confirmed the credible extraction. The alteration mineral assemblage of limonite and medium- to short-wave sericite is indicative of gold mineralization, which provide important remote sensing information for both basic geological survey and mineral resource exploration.