Abstract
The Geological Survey of Pakistan conducted an extensive geophysical investigation as part of its research and development program in 2023. The focus was on exploring metallic minerals on Aeromagnetic Anomalies (AMA-18) in the Nokkundi region of Chagai District, Balochistan. The investigation involved employing Magnetic and IP/Resistivity Wenner methods to uncover valuable insights. The survey area lies in the mineral-rich belt. The rocks in the study area include mafic to felsic volcanic with occasional sediments and ironstone intercalations. Based on the promising results from the magnetic surveys, induced polarization (IP) surveys were completed. Array results show south-east north-west trending zones of high chargeability accompanied by low resistivity. There is a zone towards the southern end of the blocks, which shows high resistivity and low chargeability. Induced Polarization was done over 52 lines to determine the apparent behavior of the anomalies with depth. The results from this survey showed the nature of the ore-body with depth and along strike. Possible drilling targets were delineated along each of these lines. Upon the project’s completion, noteworthy discoveries were made particularly in AMA-18. Within this anomaly, two distinct zones were identified and earmarked for potential iron ore drilling. Additionally, a third zone was identified in the northern part of the area, exhibiting low magnetic properties but with a high chargeability.
Further investigation expanded this area towards the north, aiming to encompass the entire anomalous zone. The extension was carried out using the Wenner IP method, a technique used for exploring subsurface properties, to thoroughly cover the identified area of interest. These findings suggest promising prospects for mineral exploration in the region, especially in terms of iron ore deposits within the marked zones. The presence of anomalies with varying magnetic and chargeability characteristics hints at diverse mineral compositions, motivating further exploration and detailed assessments in the northern extension zone. Following the findings from both the magnetic and IP surveys, three exploration wells are suggested to evaluate the potential for ore containing disseminated copper in the area. While this paper primarily discusses the IP survey and its findings, it also connects them to the physical geological mapping of exposed outcrops and magnetic survey data. A comprehensive study of the project area’s completeness will be achieved after referencing additional data from assay results obtained during the trial milling of ore extracted from the suggested exploration wells.
Keywords: Aeromagnetic Anomaly-18, Iron, Copper, Chagai, Pakistan
