--> ABSTRACT: Neotectonic Rejuvenation of the Garampani Fault and South Almora Thrust: Outer Kumaun, Lesser Himalaya, Uttarakhand, India, by Pant, P. D.; Kothyari, Girish C.; Luirei, Khayingshing; #90135 (2011)

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Neotectonic Rejuvenation of the Garampani Fault and South Almora Thrust: Outer Kumaun, Lesser Himalaya, Uttarakhand, India

Pant, P. D.1; Kothyari, Girish C.2; Luirei, Khayingshing 3
(1)Department of Geology, Kumaun University Nainital, Nainital, India. (2) Institute of Seismological Research, Gandhinagar, India. (3) Geomorphology and Tectonic Group, Wadia Institute of Himalayan Geology, Dehradun, India.

Outer Kumaun Lesser Himalaya is criss crossed by series of faults thrust planes, e.g. South Almora Thrust (SAT), Ramgarh Thrust (RT) and Garampani Fault (GF). GF is a NW-SE trending dextral strike slip fault, which forms a link between SAT and RT. The recent movements along these fault and thrust planes manifest in lateral offsetting of Kosi river, deformation of gravely unit at Bamsyu, tilting of fluvial terraces at Naugaon, westward shifting of river channel and formation of gorge with steep vertical walls in fault/thrust zone. Presence of 1.3 m thick lacustrine sediment near Kakarighat suggests episodic tectonic pulses along SAT.

Morphological and geological datasets shows active nature of GF. The recent movements along the GF have resulted in the development of tectonically induced landforms. The longitudinal river valleys show abrupt changes in gradient along the knick points. Increasing gradient of Kosi Khairna and Kuch rivers might be due to regional tectonic uplift along SAT, RT and GF. Presence of fault breccias, small scale faulting within granite mylonite and quartzite, slickenside and dextrally displaced Ramgarh porphyry are other important features of the fault zone. Granitic mylonites (Ramgarh porphyry) and quartz phyllonites (Saryu Formation) indicate ductile to ductile - brittle nature of the SAT and RT

 

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.