Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Vishwas S. Kale ¹, Avijit Gupta ², Ashok K. Singhvi ³

Affiliations
1 Department of Geography, University of Pune, Pune - 41 1 007, IN
2 School of Geography, University of Leeds Leeds, LS2 9JT, GB
3 Physical Research Laboratory, Ahmedabad 380 009, IN

Abstract

No Abstract.

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Avijit Gupta ¹

Affiliations
1 School of Geography, University of Leeds, Leeds LS2 9JT, GB

Abstract

The Mekong, the largest river in Southeast Asia, shows striking variations in channel form and behaviour along its course. It appears to link several different types of channel rather than continuing an orderly progression. Eight different river unit shave been identified along the lower 2000+ km of the river from the Chinese border to the sea across Southeast Asia. The exercise was carried out using satellite images, field visits, topographical maps, and various publications of the Mekong River Commission including large-scale river maps. The boundaries between such units are sharp and not gradual. They are different from each other depending on their morphological characteristics, their behaviour and whether the channel is bedrock-controlled. The Mekong flows for nearly 4000 km before being a freelymoving river with overbank flooding and course changes across the wide plain of Cambodia Prior to that the channel is essentially Structure-Guided it is a seasonal river with high flows during the soilthwestcr n monsoon and period floods late in the wet season. This linkage of seveial identifiable river units and the location of the present course of the river have not been properly explained. The estimated stream power of the Mekong In large floods seems to be very low when compared to what is required to erode a large channel In lock even along geological lineations. The opening of the South China Sea and the lowlands of Southeast Asia are associated with extrusion tectonics resulting from the Indian Plate colliding with the Eurasian Plate and building of the Himalaya Mountains from Eocene onwaids. The present course of the river is likely to have been determined at least primarily from this event, and possibly also associated with stronger monsoon systems in the Early Holocene as recognised for South Asia Morphology comparable to that of the Mekong seems to exist in several other major rivers of Southeast Asia and there could be a regional pattern, but investigation on this topic has hardly started.

Keywords

Mekong, Southeast Asia, River Units Tectonic Control, Satellite Images.

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R. K. Ganjoo ¹, S. N. Rajaguru ², Avijit Gupta ³

Affiliations
1 PG Department of Geology, University of Jammu, Jammu - 180 004, IN
2 Department of Archaeology, Deccan College, Pune - 411 006, IN
3 Department of Geography, National University of Singapore, Singapore 0511, SG

Abstract

Reasonably convincing evidences of neotectonic activities in the Central Narmada Valley have come to light. The geomorphic investigation of litho-sections at Bedhaghat, near Jabalpur and Siddhaghat highlights the occurrence of such event in geologically younger times. The integration of observations has further helped in understanding the genesis and dating the waterfall at Bedhaghat.

Keywords

Geomorphology, Bedhaghat Water Falls, Neotectonics, Late Pleistocene Madhya Pradesh.

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