Evaluation of EnMAP Hyperspectral Data for the Identification of Placers in the Rias Baixas Region (Spain)

Abstract

Critical Raw Materials are crucial to achieve the European Unions (EU) goals of a climate-neutral economy by 2050. The high supply risk led the EU to prioritise domestic mineral exploration. This study, part of the S34I - SECURE AND SUSTAINABLE SUPPLY OF RAW MATERIALS project, utilised remote-sensing-based methods to identify and map heavy-mineral (HM) placer deposits in the Ria de Vigo, located in Galicia, Spain. Documented since the 70s, the sands of the Vigo beaches contain placers rich in Ti, Sn, Li, Rare Earth Elements (REE), Au, Fe and Cu. Mineral mapping was performed using hyperspectral EnMAP data. Band ratios were applied to identify possible mineralisation areas. Additionally, spectral unmixing was performed through the Mixture Tuned Matched Filtering (MTMF) workflow, included in ENVI 6.0 software, and two classification maps were obtained: one utilising the USGS spectral library and the other employing an HM concentrate spectral library. Band ratios were able to distinguish possible areas of hydrothermal alteration. MTMF classifications mapped most HM known to occur in the Ria, namely sillimanite, garnet, tourmaline, ilmenite, rutile, and monazite, were identified. This first approach will allow the selection of areas of interest for field validation and verification. The results will also be confronted with existing geological data. (c) 2025 by SCITEPRESS - Science and Technology Publications, Lda.