| dc.description.abstract | The Ganges and Brahmaputra rivers transport over one billion tonnes of sediment across the Ganges-Brahmaputra-Meghna river delta (GBMD) plain each year. We investigate stratigraphic and bulk geochemical data for over 4,500 samples from a database of over 400 sediment cores drilled on the delta and construct a detailed Holocene sediment budget for the GBMD. Grain size analysis shows that overall, river valley sediments are predominantly fine to medium sized sands, while basins, interfluves, and terraces on the delta store comparatively higher percentages of mud-sized sediments. More coarse and medium sand is stored in river valleys on the upper fluvial delta plain than on the lower tidal delta plain, where increased amounts of mud, very fine, and fine sands are stored in the river valleys. Large volumes of sediment are stored in river valleys and basins while the amount of sediment stored in uplifted terrace regions is smaller, suggesting that storage, like river path, is governed by antecedent Pleistocene topography. Results show that early-Holocene sediment storage rates were ~150% greater than modern, likely in response to increased sediment delivery driven by enhanced monsoon systems. Insights from this research aim to improve understanding of GBMD growth over the Holocene with a particular focus on the ways in which sediment mass inputs, fluvial processes, and climate influence stratigraphic architecture and delta development. | |
