Landforms developed across terrain defining boundary the Main Boundary Thrust (MBT) have imprints of recent tectonic activity. Depositional landforms such as colluvial fan bear signatures of later phases of tectonic activity in the form of faulting of colluvial fan deposits and development of fault scarps. Tectonic geomorphology applied to the MBT zone suggests recent subsurface activity along the MBT and its splay thrusts. Present day tectonic activity of MBT is indicated by ground creeping, thrusting of Lower Siwalik rocks over recent colluvial fan deposit, aligning of series of lakes along splay faults and laterally along a fault, deflected streams, fault scarps and waterfalls. In the present paper we are addressing the tectonic situation in the foothill region of southeastern Kumaun Sub-Himalaya, India based on detailed field work carried out in the region which brought forward some outstanding morphotectonic evidence of neotectonic activities in the MBT zone.

are observed and have been incised by river exposing the bedrocks due to recent movement along the RT and SAT. Abandoned channel, tilted mud deposits, incised meandering, deep-cut V-shaped valleys and strath terraces indicate rapid uplift of the area. Thick mud sequences in the Quaternary columns indicate damming of streams. A ~10-kmlong north-south trending transverse Garampani Fault has offset the Ramgarh Thrust producing tectonic landforms.

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Crystalline klippen over the Lesser Himalayan Metasedimentary Sequence (LHMS) zone in the NW Himalaya have specific syn- and post-emplacement histories. These tectonics also provide a means to understand the driving factors responsible for the exhumation of the rocks of crystalline klippen during the Himalayan Orogeny. New meso- and microscale structural analyses, and thermochronological studies across the LHMS zone, Ramgarh Thrust (RT) sheet and Almora klippe in the eastern Kumaun region, NW Himalaya, indicate that the RT sheet and Almora klippe were a part of the Higher Himalayan Crystalline (HHC) of the Indian Plate which underwent at least one episode of pre-Himalayan deformation and polyepisodic Himalayan deformation in ductile and brittle–ductile regimes. The deformation temperature pattern within the Almora klippe records a normal thermal profile from its base to top but an inverted thermal profile from the base of Almora klippe down towards the LHMS zone. New fission-track data collected across the RT sheet and Almora klippe along Chalthi–Champawat–Pithoragarh traverse in the east Kumaun region document the exhumation of both units since Eocene times. Zircon fission-track (ZFT) ages from the Almora klippe range between 28.7 ± 2.4 and 17.6 ± 1.1 Ma, and from the RT sheet between 29.8 ± 1.6 and 22.6 ± 1.9 Ma; and the apatite fission-track (AFT) ages from the Almora klippe range between 15.1 ± 1.7 and 3.4 ± 0.5 Ma, and from the RT sheet between 8.7 ± 1.2 and 4.6 ± 0.6 Ma. The age pattern and diverse patterns of the exhumation rates reflect a clear tectonic signal in the RT sheet and the Almora klippe which acknowledge that the Cenozoic tectonics influenced the exhumation pattern in the Himalaya.

The aim of the present research is to provide the base line details of the NNW-SSE trending Raintoli fault (RF) which is running parallel to the North Almora Thrust (NAT) along the Saryu valley from Seraghat-Naichun to Seri in the central sector of the Uttarakhand Himalaya, India. The RF is characterized as dextral strike slip fault and behaves as a ductile shear zone within the zone of NAT. The dextral sense of shear movement of RF is delineated by the fabric of the shear zone rocks including microscopically observed indicators such as sigma and delta porphyroclasts, quartz c-axis, and the field structural data. Additionally, in the quaternary period the dextral strike slip fault is reactivated with oblique slip component as characterized by various geomorphic indicators, for example, triangular facets, abandoned river channels, unpaired fluvial terraces, and V-shaped valleys with recurrent seismicity. Further, the morphometric parameters including Valley Floor Width to Valley Height (Vf), asymmetry factor (AF), and gradient index (GI) further prove active nature of RF as suggested by low values of hypsometric integration, V-shaped valley, higher gradient index, and tilting of Saryu basin.

Talc deposits of Rema area in the Kumaun Inner Lesser Himalaya are hosted within high magnesium carbonates of the Proterozoic Deoban Formation. These deposits occur as irregular patches or pockets mainly within magnesite bodies, along with impurities of magnesite, dolomite and clinochlore. Textures represent different phases of reactions between magnesite and silica to produce talc. Petrography, XRD and geochemistry reveal that the talc has primarily developed at the expense of magnesite and silica, leaving dolomite largely un-reacted. Early fluid inclusions in magnesite and dolomite associated with talc are filled with H 2 O+NaCl+KCl± MgCl 2 ± CaCl 2 fluids, which represent basin fluid system during diagenesis of carbonates. Their varied degree of re-equilibration was although not pervasive but points to increased burial, and hence requires careful interpretation. H 2 O-CO 2 fluid with XCO 2 between 0.06 and 0.12 was equilibrated with talc formation. The reaction dolomite+quartz o talc was not extensive because T-XCO 2 was not favourable, and talc was developed principally after magnesite+quartz.

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