Spectral mineral mapping for characterization of subtle geothermal prospects using ASTER data

[摘要] In this study, the performance of ASTER data is evaluated for mapping subtle geothermal prospects in an unexplored tropical region having a number of thermal springs. The study employed a simple Decorrelation stretch with specific absorptions to highlight possible alteration zones of interest related to Geothermal (GT) systems. Hydrothermal alteration minerals are subsequently mapped using Spectral Angle Mapper (SAM) and Linear Spectral Unmixing (LSU) algorithms to target representative minerals such as clays, carbonates and AL-OH minerals as indicators of GT activity. The results were validated through field GPS survey, rock sampling and laboratory analysis using latest smart lab X-Ray Diffractometer technology. The study indicates that ASTER broadband satellite data could be used to map subtle GT prospects with the aid of an in-situ verification. However, it also shows that ASTER could not discriminate within specie minerals especially for clays using SWIR bands. Subsequent studies are aimed at looking at both ASTER and Hyperion hyperspectral data in the same area as this could have significant implications for GT resource detection in unmapped aseismic and inaccessible tropical regions using available spaceborne data.

[发布机构] Geoscience and Digital Earth Centre (Geo-DEC), Research Institute for Sustainability and Environment (RISE), Universiti Teknologi Malaysia (UTM), Malaysia^1;Korea Polar Research Institute (KOPRI), Songdomirae-ro, Yeonsu-gu, Incheon; 21990, Korea, Republic of^2

[效力级别] 无线电电子学

[关键词] Broadband satellites;Decorrelation stretches;Hydrothermal alteration minerals;Laboratory analysis;Linear spectral unmixing;Specific absorption;Spectral angle mappers;X ray diffractometers