The Capability of Sentinel-2 MSI and Landsat-8 OLI Data for Discrimination of Lithological Units and Alteration Minerals of Esfordi Phosphate Deposit Area, Central Iran

Twin Sentinel-2 MSI sensors are spatially like the Landsat-8 OLI super spectral instrument, aiming to additional data continuity for land surface monitoring were launched by European Space Agency. In this paper, the potential of these data was evaluated for discrimination of lithological units and alterations in the Esfordi phosphate deposit area and was compared with OLI and fused OLI data. Decorrelation stretch method was used for enhancing the lithological units of the study area, and all of the 3 datasets acceptably discriminated the rock units. Among these, MSI data could produce the lithological map with high resolution and highest level of reality owing to its high spatial resolution. For statistical comparison, Support Vector Machine and Random Forest methods were applied on datasets for classification of the lithological units and their accuracy was assessed using confusion matrices. Furthermore, the corresponding band ratios to which were defined for Landsat-5 TM, were applied on datasets for detecting the altered areas. Then the areas of each highlighted alteration zones were estimated for comparison. Furthermore, the scatterplots of band ratio images were prepared. MSI dataset revealed the highest overall accuracy and Kappa coefficient in Support Vector Machine and Random Forest classification. Also, the results of band ratioing showed that MSI and fused OLI data have the most correlation and similarities. This study demonstrated that MSI data are more optimal than OLI data for lithological and alteration mapping. Also, using fused OLI data in dates which there is no MSI data acquisition or for producing seamless geological maps in continental scale besides to MSI data, is efficient.