Subsurface architecture of the Wajrakarur Kimberlite Field, Dharwar Craton, India: Evidence from ground magnetic surveys

Abstract

The Ground magnetic study in the Wajrakarur Kimberlite Field and adjoining area has unveiled prominent geological variations, including felsic doming beneath the PGC-II formation to the west of the Cuddapah Basin and mafic doming beneath the Closepet Granite zone. These doming features within the upper mantle are identified as sources of mantle upwelling, which influence the emplacement of corresponding intrusive rocks. The presence of mafic chambers enhances the magnetic response, leading to localized high signatures in magnetic data and contributes to a better understanding of the subsurface composition and distribution of rock types. The present magnetic data throw lights to study the complexity of the sub-surface structure and geological activities, have shaped the study area and serve as valuable markers for understanding the geological evolution of the area. The intersections of magnetic lineament oriented in NW-SE, NE-SW, E-W yield crucial insights into geological structures and the emplacement of Kimberlite intrusions. Through comprehensive magnetic data analysis, the study offers a unique cross-sectional view of the subsurface, reaching depth up to 60 km. This perspective unveils magnetic sources and structures, revealing shallow features, interfaces of the Archaean basement, crustal roots, and upper mantle configuration. Profound magnetic gradients observed in the study area serve as indicators of fault lines influenced by tectonic activity, kimberlite intrusion, and other fault-related mineralization if any. These features contribute to a deeper understanding of the structural configurations and geological history of the area. The present study provides information about the lateral and vertical layouts of major structures as well as the deep-seated channels. It also introduces the mafic and felsic categories of rocks, explaining the complex relationships between underlying structures, geological characteristics, and magnetic anomalies.