Mapping Alteration Zones for Detection of Economic Minerals using Integrated Tools in District Lower Dir, Northwest Khyber Pakhtunkhwa, Pakistan

Abstract

The study area is the part of Lower Dir which is geographically situated in the NW of Khyber Pakhtunkhwa
province, Pakistan. Geologically this area lies in the western part of the well-known Kohistan Island Arc. It represents
the best exposure to subduction-related island arc and has been regarded as the prominent metallogenic belt that hosts a
variety of various minerals. The area has experienced various tectonic episodes in the past and altered the rock
assemblages which developed the huge potential of copper and other precious base metals. To detect and monitor these
alteration zones, remote sensing techniques coupled with field observation were evaluated in the current study.
Landsat-7, Landsat-8, and Sentinel-2B images were processed under the shelter of Principal component (Crosta
technique) analysis to demarcate the separate alteration zones. It was confirmed from the results that the signature of
the mapped alteration zone reflects the ground truth observation of copper mineralization in the target area.
Furthermore, remote sensing signatures were correlated with the petrographic details which also confirmed these
alteration zones. Spectrometry of the selected samples also delineates the same signature which is best fitted with the
remote sensing data. From our current analysis, we suggest that a principal component technique in terms of medium to
high-resolution remote sensing data is more beneficial for mineral exploration