How Ganga–Brahmaputra–Meghna delta formed

Researchers have presented a new understanding of how this mega-delta, the Ganges–Brahmaputra–Meghna delta, came together over the past 10,000 years.

Three main rivers — the Ganges, Brahmaputra, and Meghna — meet in the Bengal basin to form the world's largest delta system, which serves as a gateway between the Himalayan mountains and the vast, deep-ocean Bengal Fan.

To determine the delta's construction during the Holocene, Goodbred and colleagues followed geochemical fingerprints to trace the paths and accumulation of sediment delivered by each of the great rivers. These distinct fingerprints arise because of differences in the rocks that are being eroded in the Himalaya, Tibet, and local regions.

What is revealed is a history of mobile, interactive river systems that crisscross the landscape to build the delta, much like a 3-D printer supplied with sand and mud rather than ink.

This history reveals the patterns of river behavior that today defines the way of life for 150 million people living on the delta, who are both sustained by the fertile plains constructed by the rivers but challenged by their regular flooding and erosion.

The research has been published in GSA BULLETIN,