Integrated remote sensing and geophysical studies of the Silet-Tin Felki area: Insights into the Pan-African tectonics and magmatic evolution of the Hoggar Shield, Southern Algeria

The Silet-Tin Felki area, located within the Tuareg Shield, represents a key area for understanding the Pan-African orogeny and associated magmatic processes. This study employs a comprehensive approach, integrating remote sensing, airborne geophysics, and the previously available geochemical data to produce an enhanced lithological and structural map of the area. Remote sensing methods, including optimal RGB band combinations and principal component analysis (PCA), effectively distinguish between volcanic, granitoid, and metamorphic units. High-resolution magnetic and gamma-ray spectrometry further elucidate lithological boundaries and tectonic features, including significant shear zones. The study identifies two distinct lithological blocks, separated by the 4°50′E lithospheric shear zone: the LATEA-Aouilène block to the east, featuring Neoproterozoic high-grade metamorphic rocks, and the Pharusien Belt to the west, characterized by Neoproterozoic volcanic arc and accretionary wedge complexes. The Tonian TTG batholiths in the northern Silet region display moderate radioactivity and magnetic signatures, contrasting with the highly radiogenic post-orogenic granites.

Key geodynamic features, such as mafic-ultramafic intrusions associated with a back-arc basin, were delineated, refining the regional geological model and enhancing the understanding of magmatic evolution and tectonic interactions. The integration of gamma-ray spectrometry and aeromagnetic data enabled the detailed mapping of pre-, syn-, and post-collisional granitoids, including transitional TTG suites, and revealed complex tectonic history with significant shear zones and lineaments. This updated geological framework provides critical insights for future exploration and underscores the need for further geochronological and petrological research to fully comprehend the tectono-magmatic evolution of this part of the Tuareg Shield.