Is the Satpura “Horst” in fact a Compressional Uplift?

Abstract

ABSTRACT The >600-km-long Satpura mountain range of central India is usually considered as a horst, separated by normal faults from the Tapi and Narmada grabens. Numerous geological observations and seismicity suggest that a fundamentally different scenario is possible: the arcuate Satpura range may be a large-scale compressional uplift, riding over a north-dipping Satpura-Tapi boundary thrust, akin to the thrust-bounded regional-scale anticlines of the Columbia river flood basalt province. Erosion of the southern front of the Satpuras produces a large fault-line scarp, an illusory normal fault; close parallels exist in the Himalaya and Kachchh. The Satpura-Tapi boundary thrust is blind, buried under the post-Deccan Tapi alluvium, but periodically active, and the Tapi valley has significant seismic risk.