Intrusion and upliftment of Mahakoshal rocks between Vindhyan and Gondwana in Narmada Son Lineament, Central India

Abstract

The Narmada-Son Lineament (NSL) is one of the most prominent geomorphic features in Central India, which, divides the Indian Peninsula into two parts, northern and southern India. The present study carried near the Shahdol-Katni area of Narmada-Son lineament situated in complex transition zone, encompasses with seismically active, robust changes of gravity-magnetic field, undulating sub-surface topography, existence of hot springs and complex geological setting, which, cause the resettlement of inner dynamic progression. The area covers a range of diverse formations viz. alluvial, Deccan traps, Gondwana, Vindhyan and Mahakoshal groups with different ages. Geologically the area is divided into two parts, Vindhyan and Gondwana. The Vindhyan are exposed in the northern part and Gondwana are exposed in the southern part. It can be inferred that the Mahakoshal rocks are non-magnetic and reasonably higher density rocks which are exposed and intruded in between the Vindhyan and Gondwana rocks during the crustal resetting processes, which, may cause changes in magnetic field in the central part near Tala-Barhi area. Based on magnetic data, the area can also be divided into two parts, the northern part containing higher magnetic values (upto 900 nTesla) and the southern part with the values upto -1000 nTesla. The resettlement process may cause the separation of Vindhyan and Gondwana rocks because of the two existing active faults viz. Son Narmada North Fault (SNNF) and Son Narmada South Fault (SNSF). To know the geological setting of the Narmada Son Lineament, the knowledge of basement depth study plays a major role for understanding the inner mechanism of structural scenery of the ground sub-surface. There are number of studies carried out in and around the study area, but present technique plays an important role with sufficient evidences to validate the structural setting carried by the earlier geoscientists. Werner and Euler deconvolution techniques have been jointly carried out over the study area on the available magnetic dataset for basement depth estimation. As per study, the basement depth varies from 4 km to 5 km in the central part compared to both the split ends of the profiles, which, convincingly correlate the consequences carried by earlier studies. As the magnetic method can provide a non-unique solution, it is always recommended for integrated approach for better understanding and substantiation.