Utilization of USGS Spectral Signature Processing in Croatian Gypsum Exploration

A detailed previous study of the potentiality of mineral raw materials in the Vrlika karst polje showed a high geological gypsum potential that was not precisely determined on existing geological maps. This serves as the primary scientific reason for selecting this study area. The second reason arises from market demands for an increased supply of gypsum, recognized as an environmentally friendly mineral raw material by the Eurogypsum Association. To rapidly assess the 25 km2 area, remote sensing methods were employed. Data collected from the USGS (the United States Geological Survey) was used, with their scientists having created a database of spectral signatures. By using spectroscopy to study materials, measurements can be compared to the spectral records of sensors located on different platforms, in this case, the ESA´s (the European Space Agency) MSI-Sentinel- 2A. The K-means algorithm and NDVI based on WV3 sensor were also used. Comparative analysis of the obtained data with field data led to the conclusion that spectral signatures of gypsum from USGS samples align closely with those from Croatia due to their very similar chemical composition, taking into account the spatial resolution of MSI-Sentinel-2A.