J. Earth Syst. Sci. (2020) 129 56 Ó Indian Academy of Sciences https://doi.org/10.1007/s12040-019-1326-z (0123456789().,-volV)(0123456789().,-volV) Mapping of basement structure beneath the Kohima Synclinorium, north-east India via Bouguer gravity data modelling 1 1 1 2, CH RAVI KUMAR ,NKESIEZIE ,BPATHAK ,SAUMEN MAITI * 3 and R K TIWARI 1 Geological Survey of India (GSI), NER, Shillong 793 006, India. 2 Indian Institute of Technology (Indian School of Mines), Dhanbad 826 004, India. 3 CSIR–National Geophysical Research Institute, Hyderabad 500 007, India. *Corresponding author. e-mail:
[email protected] MS received 3 January 2018; revised 18 October 2019; accepted 29 October 2019 Kohima Synclinorium is one of the most tectonically active corridors of Indian subcontinent and displays complex tectonics of the region. Mapping the basement structure beneath the Kohima Synform is, therefore, vital to provide deep insight into the understanding of the crucial thrust geometry of the region. The vertical gravity gradient anomalies and available geological evidences suggest that the underlying area is occupied by thrust geometry embedded with prominently known tectonic trends of Schuppen Belt (SB), Kohima–Patkai Synclinal (KS–PS) and adjoining Inner Fold Belts (IFB). By keeping in view the massive complex tectonic upheaval in the region, we carried out 2D Bouguer gravity data analysis using the radially averaged power spectral techniques and GMSYS modelling to map the basement depth more precisely. Our results suggest that there is a wide range of heterogeneity in the underlying undulating basement indicating an average sedimentary thickness of the order of 2.2–5.5 km.