Geological and structural analysis of the Almora klippe, India, NW Himalaya

We present a new geological map and accompanying structural analysis to constrain the tectonic evolution of the Almora klippe, in the Kumaun Indian Himalaya. The map comprises a detailed individual lithology map of the Almora klippe and the first documentation of the Tethyan Sedimentary sequence and South Tibetan Detachment system shear zone in the klippe. Detailed field mapping is supported by cross sections, petrology, and quartz crystallographic preferred orientation analysis. We propose that changes in the structural geometry, such as the steepening of foliations and mineral lineations from west to east, the deepening of the Main Central Thrust shear zone from west to east, and a lateral ramp within the central portion of the mapped area are most consistently explained by the reactivation of the cross-strike Moradabad Fault in the underthrusted Indian plate. This study demonstrates that along-strike geological mapping can reveal evidence of reactivation of basement faults during orogenesis.