Spectral Angle Mapper and aeromagnetic data integration for gold-associated alteration zone mapping: a case study for the Central Eastern Desert Egypt

ABSTRACT

The Spectral Angle Mapper (SAM) classification technique is integrated with the surface structure and aeromagnetic data to map the potential gold mineralization sites associated within alteration zones in Central Eastern Desert (CED), Egypt. The surface reflectances of the Enhanced Thematic Mapper Plus (ETM+) and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data were classified using the SAM classifier. Five spectral reflectance curves of the alteration minerals (haematite, illite, kaolinite, chlorite, and quartz) were utilized as end-members for the SAM classification. The surface lineation, and shear zone systems were delineated using ETM+ bands. The deep-seated faults were defined using the Euler deconvolution filter on the gridded aeromagnetic data. The magnetic data analysis inferred the subsurface structural depths range from 500 m to 2000 m. Geographic information system (GIS) overlaying operation was performed using the surface lineation and the subsurface faults layers to identify the structural continuity and to extract the possible migratory pathways of the hydrothermal solutions. Within Multiple Criteria Decision Analysis (MCDA), fuzzy membership operations were applied to identify the prospective alteration sites. The mapped results were compared with global positioning system (GPS) locations of existing alteration zones. The current proposed mapping method is considered a robust tool for decision-making and potential site selection technique for further mineral exploration in CED.

Acknowledgements

The first author acknowledges the Mission sector of the Egyptian Ministry of Higher Education and Scientific research for providing the financial support to conduct this research in the USA through a PhD scholarship. Thanks goes to the Advanced Radar Research Center (ARRC) group and the Hydrometrology and Remote Sensing Laboratory (HyDROS) research group at the University of Oklahoma (OU) for providing the research facilities and lab equipment for this work. We really appreciate the comments of two anonymous reviewers that helped us improve the overall quality of the manuscript. Additionally, thanks goes to the OU writing center and to Race Clark for their help in the manuscript proofreading and the English corrections.

The ETM+ and ASTER data sets are obtained from the Land Processes Distributed Active Archive Center (LP DAAC), and the spectral reflectance curves are obtained from the USGS.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The author would like to thank the Mission sector of the Egyptian Ministry of Higher Education and Scientific research for providing the financial support to conduct this research in the USA through a PhD scholarship.