Bitumen zoning in Khuzestan Province, southwestern Iran: an integrated approach using remote sensing, spectroscopy, and analytical hierarchy process (AHP)

This research explores the spatial distribution of natural bitumen in Khuzestan Province through a novel integrated approach that combines Sentinel-2 satellite imagery, spectral data from the FieldSpec3 spectroradiometer, and the Analytic Hierarchy Process (AHP). The study addresses the existing gap in integrating spectral analysis with multi-criteria spatial modeling to enhance the precision of bitumen mapping. This combined methodology represents the first-time application of such an integrated approach in this particular region. Field data were gathered from three mines: Ahangaran, Ghaland, and Dodangeh. Twelve bitumen samples were collected and analyzed spectrally. Results obtained using TSG and PRISM software showed that the Ghaland mine samples had the most pronounced absorption features in the 1.69 to 1.79 μm range, suggesting a higher concentration of heavy hydrocarbons. Across all samples, heavy hydrocarbons consistently exceeded light hydrocarbons. Classification using the Spectral Angle Mapper (SAM) method achieved 91 % accuracy and closely aligned with field observations. In the spatial modeling phase, five information layers were incorporated: oil fields, bitumen mines, faults, anticlines, and key geological formations. These layers were weighted and integrated within a GIS environment to produce a bitumen probability map. The map was compared with the SAM classification results, showing significant overlap in high-potential zones, which supports the validity of the applied approach. In both methods, the eastern region of the study area exhibited the highest bitumen occurrence potential. Out of the total 64,057 km 2 area of Khuzestan Province, about 0.011 km 2 (roughly 11,000 m 2 ) was identified as zones with high potential for bitumen occurrence.