BASEMENT DELINEATION IN INDO-GANGETIC ALLUVIAL PLAINS BASED ON GRAVITY DATA

Abstract

Till date, basement .tectonics delineation through gravity in Indo-Gangetic Plains is limited to constant density contrast models. Here, an attempt is made to use variable density variation with depths for basement delineation in IGP using gravity. Based on published Bouguer gravity anomaly data, the basement configuration of a part of Indo-Gangetic Plains is deciphered with the help of 3D gravity inversion algorithm. This algorithm accounts for variable density contrast variation with depth, and calculate the depth of density interface using the residual anomaly data. Basement depth map has been derived from the gravity. The basement exhibits a block structure bounded by many faults and having several local highs and lows. The proposed Delhi-Haridwar ridge seems to be simplistic concept and it extends upto Muzaffamagar. Several depocentres have been observed in the study region. A NW-SE trending fault parallel to HFT has also been demarcated The study indicates that basement faults run parallel to HFT and orthogonal to it thereby leading to blocky structure with various depocentres. These basement faults can be linked to Himalayan orogeny 3