Geological mapping using drone-based photogrammetry: An application for exploration of vein-type cu mineralization

Abstract

In this research, drone-based photogrammetry was utilized for mapping geology with the objective of mineral exploration in the Shahzadeh Abbas Cu deposit, Kerman province, Iran. Cu mineralization is of vein-type and follows geological structures. A low-cost drone was used to collect geological data. A spatial resolution of 3.26 cm was achieved by considering a flight altitude of 70 m. To reach the accuracy of less than 5 cm, 70% lateral and 80% front image overlaps were applied and 220 temporary ground control points (TGCPs) were used in an area of 2.02 km2 . TGCPs were accurately positioned using DGPS-RTK measurements. Agisoft PhotoScan software was used for photogrammetric processing. The orthophoto product was performed for outlining geological units through visual interpretation. The digital elevation model (DEM) was converted to a hill-shade model in ArcGIS software to extract the geological structures such as faults and dikes. A draft geology map was prepared using orthophoto and hill-shade images to minimize the time and cost of the subsequent field work. Rock sampling was carried out and Cu-bearing veins were specified through field investigations. The geology map was finalized based on field work data and petrology studies. The geological survey indicated that diabase dikes with a northwest–southeast strike often host Cu mineralization in the study area. The position of Cu-bearing dikes was delineated for the next stage of the exploration program. This research demonstrated the time-and cost-effectiveness of using drone-based photogrammetry for preparing base geology maps for the exploration of vein-type mineralization in far districts with rough topography.