Identification of significant subsurface geological structural feature using gravity and magnetic survey in parts of Kamrup district, Assam and West Khasi Hills district, Meghalaya

Gravity and magnetic survey have been carried out in parts of the Kamrup district of Assam and the West Khasi Hills district of Meghalaya. The objective of the survey is to delineate the subsurface geological structure and identify the mineralization potential zone. Regional-residual separation, radially averaged power spectrum, Euler's depth solutions and 2D-depth model maps mainly have been analyzed for interpretation. High Bouguer anomalies were observed over exposed Assam–Meghalaya gneissic complex (AMGC) rocks whereas low anomalies were observed over quaternary sediments. The general trend of the gravity and magnetic contours are in the NE–SW direction which is also the trend of geological formations, i.e., AMGC and older metamorphic group rocks. Based on Bouguer contours several inferred contact/lineament/faults have been identified. These contact/lineament/faults are very well validated with Euler’s depth solutions and total horizontal gradient of gravity anomaly. Significant high magnetic anomalies have been observed over older metamorphic group rocks and the Assam–Meghalaya gneissic complex. After the correlation with the physical properties of rock samples, geology and interpretation of gravity and magnetic maps, a potential zone has been identified for detailed investigation from a mineralization point of view.