Structural analysis and susceptibility inversion based on ground magnetic data to map the chromite mineral resources: a case study of the Koh Safi Chromite Ore Deposit, Parwan, Afghanistan

Abstract

Abstract The Koh Safi Chromite Ore Deposit is located in Afghanistan’s northern–northeastern end of the Kabul–Kandahar ophiolite zone. Sedimentary formations, delayed volcanic, and ultramafic rock groups, including peridotites and serpentinites, could all have been found in the Koh Safi area, where structural discontinuities with the two trends of northwest–southeast and east–west can be identified. High-grade serpentinite units have many chromite deposits, whereas peridotite has a lot of medium-grade deposits. This paper performs a ground magnetic data analysis based on structural analysis and 3-D susceptibility inversion. The boundaries of structural faults and anomalous bodies are likely delineated in a northwest-to-southeast orientation using a series of derivative maps, including Total Horizontal Derivative, Analytical Signal, and Theta Map. For inversion, many regularization norms that included the range of smooth, intermediate, and compact models were used to examine a particular susceptibility value that occurred in a model cell. The sparse and blocky norms [0,1,1,1] were suggested for our inversion in field data based on synthetic data to determine an appropriate norm. A 3-D inversion of ground magnetic data shows that the highly magnetic zone supposed to be the host rocks seems to be where chromite occurs in the study area.