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Ophiolites are remnants of oceanic crust that have been thrust onto continental crust due to tectonic processes. They are composed of mostly mafic and ultramafic rocks, which are genetically associated with gold, silver, platinum group element (PGE), chrome, manganese, titanium, cobalt, copper, and nickel deposits. The main objective of this research was to identify the spatial distribution of Mesozoic ophiolitic complexes within the Central Afghan Block in Middle Afghanistan using optical remote sensing data and spectral analyses. Distinct algorithms, such as false color composite (FCC), proposed band ratios (PBR), principal component analysis (PCA), and spectral angle mapper (SAM), were used to map the targeted ophiolitic complexes. New band ratios were proposed in this study based on the spectral properties of mafic-ultramafic minerals and rocks, which showed high efficiency. Based on the results, four different ophiolitic complexes were delineated within this study area. These complexes are consistent with previous studies. The accuracy assessment of this study showed an overall accuracy of 72.2%. The findings of this study can significantly contribute to further studies on the emplacement mechanism and paleo-Tethys history of Middle Afghanistan. Also, the spatial distribution of the ophiolitic complexes identified in this study can be used to constrain models of the tectonic evolution of the Central Afghan Block. Additionally, the identification of new band ratios for mapping ophiolitic complexes can be used in future studies of other ophiolite-bearing regions. [ABSTRACT FROM AUTHOR]

Afghanistan comprises a collage of many lithotectonic domains sutured together as block terranes on the southern Eurasian Plate by collisional tectonics throughout the Proterozoic and Phanerozoic. Kabul basement rocks are fragments of an Archaean block stabilized in early Precambrian with two later metamorphic events correlating well with global-scale orogenies related to assembly of the Paleoproterozoic Columbia and Neoproterozoic Rodinia supercontinents. These collisional tectonics were followed by igneous episodes and production of multiple ophiolite suites divided into three orogenic episodes of the later Palaeozoic (Devonian – Permian) Variscan (Hercynian) Orogeny, the Mesozoic (Triassic – Early Cretaceous) Cimmerian Orogeny, and the dominantly Cenozoic (Late Cretaceous – Quaternary) Himalayan (Alpine) Orogeny. Variscan, Cimmerian, and Himalayan accreted blocks are separated by prominent suture and fault zones, several of which are active and a source of considerable seismic hazard, especially in eastern Afghanistan. This resulting mélange of small exotic blocks was brought about by a rifting series of narrow ribbon terranes from the Gondwana coast of the Paleotethys and Neotethys seaways. Recent revival of Afghan-led geological lithologic and geochemical assessments has led to new interpretations of tectonic history, as well as of vital surface and groundwater, and other natural resources. Recurrent droughts have decreased water supplies, which have undergone extensive contamination, along with uncontrolled over-pumping of aquifers. Increasing attention to the rich mineral resource base in the country offers solutions to chronic budgetary shortfalls. [ABSTRACT FROM AUTHOR]