Crustal structure and lateral variations in Moho beneath the Delhi fold belt, NW India: Insight from gravity data modeling and inversion

Publication date: December 2019Source: Physics of the Earth and Planetary Interiors, Volume 297Author(s): Divyanshu Dwivedi, Ashutosh Chamoli, Anand K. PandeyAbstractThe Proterozoic Delhi fold belt (DFB) in NW India shows a prominent NNE-SSW trending gravity high, but its northward extension beneath Gangetic alluvium lack understanding. We model the gravity anomaly using radially averaged power spectrum, depth from extreme points (DEXP) method, wavelength filtering, 3D structural inversion to constrain crustal structure of the DFB. The radially averaged power spectrum analysis suggests three interfaces and the DEXP method indicates presence of a horizontal cylindrical source below the DFB. The 3D structural inversion shows depth variation from 39 to 46 km in the study region and presence of an upwarp below the DFB and Sandmata complex. Our modeling suggests that an underplated mafic material possibly a residual plume head produces gravity high. The transverse structure of DFB is absent beneath Gangetic alluvium and show notable westward deflection in line with the NW-SE trending Delhi-Sargodha ridge. The transverse DFB attains westward deflection possibly due to NW indentation and counterclockwise rotation of Indian plate after Himalayan collision in Eocene. With continued convergence, this DFB structural element at the leading edge of Indian peninsula got involved in flexural upwarp of underthrusting Indian plate beneath the Himalaya.
Source: Physics of the Earth and Planetary Interiors - Category: Physics Source Type: research
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