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Joshi, D. D.
- Erosion Intensity in a Mountain Watershed in the Himalayan Region
Authors
1 Department of Geology, University of Delhi, Delhi 110 007, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 24, No 10 (1983), Pagination: 533-539Abstract
A simple method for mapping of erosion intensity in a mountain watershed based on assignment of qualitative indices to various categories of geomorphic features, mean ground slopes and lithological cum structural state of the bedrock is proposed.
A preliminary case study has been conducted in a part of the Ravi drainage basin in the Himalayan region. The major geomorphic features observed are fill-cut and strath terraces, alluvial fans, landslides, small talus cones and debris-flow deposits. The slopes range from 4° to 41° and have been divided into seven classes consisting of 6° intervals each. Lithologically, the area consists of phyllite, quartzite, slate, limestone, conglomerate and granite. An erosion intensity map of this region indicates that most of the high erosion areas lie close to the main river and their distribution is controlled mainly by the recent drift material and the valleyside slopes.
Although this method is qualitative, it can be useful for a preliminary evaluation of erosion intensity. and for delimiting high erosion areas for environmental planning.
- Geomorphologic Development Across the Active Main Boundary Thrust, An Example from the Nainital Hills in Kumaun Himalaya
Authors
1 Kumaun University, Nainital 263001, IN
2 University of Delhi, Delhi 110 007, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 25, No 12 (1984), Pagination: 761-774Abstract
The Main Boundary Thrust marking the tectonic junction between the Lesser Himalaya and Siwalik molasse represents a zone along which underthrusting still occurs. Depositional terraces formed as a consequence of subrecent and historical landslides have been faulted and displaced vertically as well as horizontally in the Balia Valley, which follows the zone of the Main Boundary Thrust. Vertical scarps and triangular facets on the hillsides, uplift and dissection by faults of terraces and landslide fans, and presence of abandoned valleys across the Main Boundary Thrust, further bear testimony to recent movements. The burden of evidence points to uplift of the Siwalik domain by 30 to 80m relative to the Lesser Himalayan belt.- Quaternary Valley-Fill Deposits of the Ravi Drainage Basin in Chamba, Western Himalaya: Definition, Lithostratigraphy and Depositional Framework
Authors
1 Department of Geology, University of Delhi, Delhi 110007, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 29, No 6 (1987), Pagination: 540-553Abstract
Quaternary deposits in the Himalaya fall into two major categories: Group 1-lntra-montane basinal fills occurring in various tectonic zones, and valley-fill sequences of limited width along the linear extent of major Himalayan drainages and Group 2-Sub-montane basinal fills in the foot-hills zone. The Mangla Formation (250m thick) is being defined from one of the major Himalayan drainages-the Ravi river. It is divided into six members representing paraglacial fan and braided stream deposits. The 'glacial' history of the sequence has been inferred from the physical environment of the terrain. and by relating the deposits to the gross geomorphological features.
Attempts to correlate the Mangla Formation with the glacial deposits in the Himalayan region, particularly Swat Kohistan and the southern slopes of the Dhauladhar range, are beset with difficulties in the absence of a proper chronology of Quaternary glacial events in the Himalaya. Two major ice advances have been interpreted in the Dhauladhar Range. In the absence of datable materials, no meaningful temporal relationships can be established for the ice advances.
- Geomorphic History and Lithostratigraphy of a part of Eastern Gangetic Plain, Uttar Pradesh
Authors
1 Geological Survey of India, Jaipur 302001, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 37, No 6 (1991), Pagination: 569-576Abstract
The Quaternary deposits of the area are classified into three lithounits, viz., Varanasi Older Alluvium, Chhoti Sarju Older Flood Plain Deposits and Chhoti Sarju Recent Flood Plain Deposits. The facies organisation of the Varanasi Older Alluvium (+300 m thick), indicates a braided to meandering river environment for the lower sandy facies and meandering river to local lacustrine conditions for the upper silt clay facies. Presence of a regionally persistent shell-bearing silty-clay horizon (at a depth of about 1 m to 2 m below ground level) indicates commencement of lacustrine conditions towards the waning phase of sedimentation of Varanasi Older Alluvium. The Chhoti Sarju Older Flood Plain Deposits rest over the eroded surface of Varanasi Older Alluvium. This deposit is about 10 m thick with fining upwards sandy facies deposited in a meandering river regime. The Chhoti Sarju Recent Flood Plain Deposits are confined within a very narrow zone (approx. 250 m wide) in the bed portion and flood plain of the river. In this regime, the sedimentation is still going on in the form of point bars, channel bars and side bars. At places, lacustrine conditions (oxbow lakes) are also present.
The Quaternary history of the area indicates at least two prominent episodes of base-level (sea-level) rise during the Late Pleistocene-Holocene period.
Keywords
Quaternary, Eastern Gangetic Plain, Geomorphology, Uttar Pradesh.- Jaisalmer Earthquake of 1991; Its Effects and Tectonic Implications
Authors
1 Geological Survey of India, Western Region, Jaipur, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 49, No 4 (1997), Pagination: 433-436Abstract
An earthquake having magnitude 5.6 (USGS) on Richter scale occurred in the Jalsalmer area on 8th November, 1991. Having maximum Intensity of VII+.Full Text
- Signature of Quaternary Tectonics in a Part of Dehradun Valley, Uttaranchal
Authors
1 Geological Survey of India, Lucknow - 226 024, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 67, No 2 (2006), Pagination: 147-150Abstract
Signatures of active tectonics have been observed in the eastern part of Doon valley in proximity to a lineament (fault?) cutting across the Himalayan grain. A normal fault has been observed over the Doon sediments represented by a sequence of silty clay, gravel and clay exposed in a quarry section. The fault displaces the litho sequence with a vertical throw of 1 5 m. This suggests tectonic movement along the fault during Quaternary period.Keywords
Neotectonics, Quaternary, Doon Valley, Uttaranchal.Full Text
- Geoenvironmental Problems of the Glacial Belt of Bhutan Higher Himalaya and Remedial Measures: A Case Study of Raphstreng Lake in Lunana Area
Authors
1 Geological survey of India, Northeastern Region, Shillong, IN