The Late Eocene-Early Miocene Unconformities of the NW Indian Intraplate Basins and Himalayan Foreland: A Record of Tectonics or Mantle Dynamics?

摘要: A well-developed Late Eocene to Miocene unconformity, termed the Base Unconformity (BMU), is found throughout intraplate basins of north-western India, and has previously been ascribed Himalayan tectonics. This hypothesis investigated by first describing nature age BMU in northwest Indian basins, then reconstructing location relative deformation front at time it formed. We suggest that formation western India cannot be related tectonic processes associated with plate loading flexure unless had an elastic thickness >125 km, which highly unlikely. Furthermore, resumption deposition post-unconformity rules out inversion due compression India-Asia convergence as a cause, these compressive forces are still present. note coeval unconformity NW peripheral foreland basin. If unconformities basin formed common process, uplift circulation mantle only possible regional-scale mechanism. Such could result intrinsically time-dependent high-Rayleigh number convection mantle, resulted well-documented elsewhere, or subducting slab break-off beneath Himalaya.