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P. D. Pant ¹, O. P. Goel ¹, Mallickarjun Joshi ²

Affiliations
1 Department of Geology, Kumaun University, Nainital 263 002, IN
2 Department of Civil Engg., Institute of Technology, BHU, Varanasi 221005, IN

Abstract

Thrusts, fold axes and fault zones in the Loharkhet area in the northern part of Almora district in Uttar Pradesh, record reactivation during Neogene times. Several alluvial and colluvial deposits in the area are being vertically and horizontally offset, and tilted by active folding and faulting. The recent movements along the Ravetiganga overturned anticline and Dulam Gadhera- and Vongarh-Gason-faults have not only uplifted the Nasati-Rithabagar block by about 103 m, but have shifted also the original confluence of the Sarju and Ravetiganga rivers by 11 km southwestward.

The ESE-flowing Gurkhula Gad and Mehar Gad streams have been deflected towards SSE direction by the recent strike-slip movements along the Kaphlikot-Ramari Fault. The Ramari landslides fan has been displaced vertically by 3 m along this fault. Terraced toe of the colluvial cone of the Badiyakot landslide has been displaced dextrally and uplifted by 18 m along the NNW-SSE striking Ghatia Gad Fauh.

The geomorphic expressions of the various tectonic zones indicate both vertical and strike-slip displacements. Rejuvenation of the earlier mature terrain is borne out by topographic changes that have taken place in the recent past. The topographic development indicates continuing uplift in some sections of Vaikrita (MC) Thrust and Berinag Thrust and the zone of the Ravetiganga overturned anticline. Relatively higher rate of uplift is observed for the MCT zone.

Keywords

Neotectonism, Geomorphology, Kumaun Himalaya.

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B. N. Singh ¹, O. P. Goel ¹, Mallickarjun Joshi ², J . W. Sheraton ³

Affiliations
1 Department of Geology, Kumaun University, Nainital 263 002, IN
2 Geology Laboratory, Department of Civil Engineering, Institute of Technology, Banaras University, Varanasi-221 005, IN
3 Australian Geological Survey Organisation, P. O. Box 378, Canberra City, A.C.T. 2601, AU

Abstract

Early Cambrian Champawat granitoids from Dhunaghat area, emplaced between medium-to high-grade metapelites of the Saryu Formation and low-grade melapelites of the Gumalikhet Formation of the Almora Group, show wide variations in their modal and chemical composition, ranging from granodiorite to granite. Biotite-rich mafic enclaves within the granitoids may represent restile, possibly modified by metasomatism. Chemical data for the calc-alkaline Champwat granitoids show some dcgree of fractional crystallization, although processes such as restite unmixing and different degree of melting may also have been important for the observed variation trends.

The Champwat intrusives are also characterized by enrichment of Y, Zr, Th, U, Nb, La, Ce, Pr and Nd and show affinities with "A"-type (anorogenic) granites.

Keywords

Geochemistry, Petrogenesis, Champawat graniloids, Almora Group, Dhunaghat, District Pithoragarh, Uttar Pradesh.

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B. N. Singh ¹, O. P. Goel ², Mallickarjun Joshi ¹, J. W. Sheraton ³

Affiliations
1 Geology Laboratory, Department of Civil Engineering, Institute of Technology, Banaras Hindu University, Varanasi - 221 005 (India), IN
2 Department of Geology, Kumaun University, Nainital - 263 002 (India), IN
3 Australian Geological Survey Organisation, P.O. Box 378, Canberra City, A.C.T. 2601 (Australia), AU

Abstract

The Precambrian Almora granite gneisses containing numerous schistose enclaves occuras thick and thin bands within the medium-grade Saryu metasediments of Almora Group. Petrography and major and trace element geochemistry of the granite gneisses indicate that they are strongly peraluminous, S-type granites, and were derived by partial meltingofthe meta-arkose/metapelites.

Keywords

Geochemistry, Granite, Dhunaghat, Uttar Pradesh.

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B. N. Singh ¹, Mallickarjun Joshi ²

Affiliations
1 Geology Laboratory, Department of Civil Engineering, Institute of Technology, Banaras Hindu University, Varanasi- 221 005, IN
2 Department of Geology, Banaras Hindu University, Varanasi - 221 005, IN

Abstract

The occurrence of Malani rhyolites as dykes within the Mt. Abu batholith has been studied. The Mt. Abu rhyolitic dykes are peraluminous and of subalkaline nature. These are enriched in trace elements such as Rb, Nb, Zr, Y, Ga, Th and Zn, and depleted in Ba and Sr resulting in high K/Rb, Rb/Sr, Ba/Sr and Ga/AI ratios. The geochemical characters indicate Mt. Abu rhyoiitic dykes to be A-Type, within-Plate granites (WPG) with high SiO₂, Na₂O + K₂O and Fe/Mg. These rhyolites are likely to have formed in anorogenic Rift-Related setting and the volcanism may be correlated to early stages of Pan-African magmatic event (850-750 Ma).

Keywords

Rhyolite, Geochemistry, Mt. Abu Batholith, Rajasthan.

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Mallickarjun Joshi ¹, Jitendra K. Raj ²

Affiliations
1 Department of Geology, Banaras Hindu University, Varanasi - 221 005, U.P., IN
2 Department of Civil Engineering, Banaras Hindu University, Varanasi - 221 005, U.P., IN

Abstract

Neotectonic rejuvenation is conventionally inferred from field observations of various geomorphic features. All such observations essentially aim at distinguishing geomorphic features characterizing marked increase in ruggedness ofthe topography. We use fractal dimensionality on an example from Kakrighat area, Kumaun Himalaya, to characterize the degree of ruggedness of the terrain for its geomorphologically homogeneous sectors and demonstrate that fractal dimensionality increases with increasing roughness of the terrain and can be used to identify neotectonic activity.

Keywords

Fractal Dimension, Neotectonic Activity, Geomorphic Parameters, Drainage, Kakrighat, Kumaun Himalaya.

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Jiwan Singh Rawat ¹, Ajit Govind ², Geeta Rawat ¹, Mallickarjun Joshi ³, Shive Prakash Rai ⁴, Navneet Gahlot ¹

Affiliations
1 Department of Geography, Kumaun University, SSJ Campus, Almora 263 601, IN
2 Department of Geology, University of Kerala, Thiruvananthapuram 695 581, IN
3 Department of Geology, Banaras Hindu University, Varanasi 221 005, IN
4 National Institute of Hydrology, Roorkee 247 667, IN

Abstract

Under a changing climate, the Sub-Himalayan ecosystems are likely to experience marked transformations in hydrological, biogeochemical and biophysical processes. To explore this, we have been observing various hydrometeorological parameters in a completely rain-fed sub-Himalayan watershed (Salla Rauetella Watershed) since 1991. We noted a changing trend for some of the hydrometeorological parameters over the 22-yr period. While the annual air temperature has increased significantly, the annual rainfall also shows an increasing trend with a higher probability of increased rainfall intensity. The run-off data show a peculiar trend that the watershed has been transforming itself from a perennial to an ephemeral system, despite an increasing trend of rainfall magnitudes. This is primarily attributed to the increasing trends of rainfall intensities exceeding the infiltration capacities of the soil which trigger large but high-intensity run-off events with dry spells in other periods, which makes the river ephemeral. We infer a likely dynamic change in the run-off-generation mechanism which warrants the need for a more precise and rigorous observation-cum-measurement strategy of ecohydrological processes in Himalayan ecosystems, supported with modelling and remote sensing approaches. This will help identify the optimal headwater treatment measures for augmenting groundwater to sustain the rainfed streams of the Himalaya under a changing climate.

Keywords

Climate Change, Ecosystem Transformation, Precipitation Trends, Run-Off Generation, Watersheds.

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