Paleo Meander scars as a Sedimentological Proxy for past discharge estimation in the Bengal Basin

Basumatary, Dipjyoti (2021) Paleo Meander scars as a Sedimentological Proxy for past discharge estimation in the Bengal Basin. Masters thesis, Indian Institute of Science Education and Research Kolkata.

Text (MS Dissertation of Dipjyoti Basumatary (16MS032)) 16MS032_Thesis_file.pdf - Submitted Version Restricted to Repository staff only Download (4MB)

Abstract

Fluvial deposits serve as ancient archives to attain several objectives regarding past climate reconstruction, Paleohydrology, and more. Meandering rivers frequently abandon their loops in response to several factors but mainly discharge. Lower Ganga plain in West Bengal is enriched with numerous Oxbow lakes, five oxbow lakes investigated for grain size analysis, geochemical studies, and OSL dating. Paleo discharge estimation is somehow more feasible for bedrock rivers, but it is not that easy for alluvial rivers like Ganga (Hooghly). Formula stating relation between wavelength, discharge, and channel silt-clay (Schumm et al., 1968) first verified and used to calculate the past discharge in the study area. Several facies drawn from field studies possess paleo flood stacks (Fine sand and silt-clay) through various point bar exposures. OSL dates acquired from flood packages match well with the warm and wet phases over the Indian subcontinent with ages 0.58ka, 0.94ka, 1.0ka, 2.94ka, 3.92ka consequently. The present study provides a way to calculate the paleo discharge for alluvial rivers and decipher the utility of point bars as a tool for monsoonal reconstruction in the study area.

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