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P. D. Pant ¹, Girish C. Kothyari ¹, Khayingshing Luirei ²

Affiliations
1 Department of Geology, Kumaun University, Nainital - 263 002, IN
2 Wadia Institute of Himalayan Geology, Northeast Unit, ltanagar - 791 113, IN

Abstract

Significant evidences of neotectonic activity have been observed in Seraghat-Basoli area along the Saryu river valley in the Central Kurnaun Lesser Himalaya. The geomorphic and structural features indicate that the Saryu River Fault (SRF) in the area has displaced North Almora Thrust(NAT) and is still active. The tectonic rejuvenation of the NAT and SRF has resulted in the development and deformation of tectonic landforms such as unpaired terraces, tectonic flats, fault scarps and triangular cones and facets. The strike slip movement along the SRF fault has resulted not only straightening of the Saryu river course but the course has also been shifted from NW-SE to almost N-S direction, particularly between Naichan and Seri. The uplift of fluvial terraces by 44 mat Nali and deposition of almost 3 5 m thick siltymud and silt the beginning of the deposition of levee flood plain at Ara suggests that the area is tectonically active Shifting river courses, stretching and straightening of river channels and the levee flood plain depositional environment indicate that the neotectonic activity in controlling this domain of NAT.

Keywords

North Almora Thrust, Saryu River Fault, Neotectonics, Kumaun Himalaya, Uttaranchal.

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Khayingshing Luirei ¹, P. D. Pant ², Girish C. Kothyari ²

Affiliations
1 Wadia Institute of Himalayan Geology, Northeast Unit, Itanagar - 791 113, IN
2 Department of Geology, Kumaun University, Nainital- 263 002, IN

Abstract

The northeastern Kumaun part of Kumaun Lesser Himalaya is seismotectonically one of the most active segments of the Central Himalaya. The major as well as minor thrusts and faults in Dharchula and its environs are neotectonically quite active and as such their movements have made this region vulnerable to landslides. Dharchula and its environs have been affected by number of earthquakes. The recent tectonic movements along these thrusts and faults are expressed in the geomorphic rejuvenation of the terrain such as entrenched meandering, river courses characterized by deep gorges, unusual widening of the river valleys, formation of the palaeolakes, deflection of rivers, and offsetting of the river terraces. Abrupt deflection of Kali river course from general flowage i.e. NNE-SSW to E-W is observed, which reflect the rejuvenated movements of the faults. Reactivation of the fault has resulted in the formation of six levels of terraces in Gathibagar. Relicts of lacustrine deposits formed due to abrupt changes in the drainage regime are also observed along Jauljibi-Dharchula section.

Keywords

Neotectonics, Episodic Uplift, Seismotectonics, Terraces, Northeastern Kumaun, Uttaranchal.

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