The geographical mass that constitutes the small, but thickly populated, country of Bangladesh was formed in a unique geological process, according to a consortium of Indian and US earth scientists. As reported in September 2019, researchers state that soil erosion over a very long period with massive volumes of sediment brought in by the rivers Ganges and Brahmaputra from the Himalayas buried the primitive oceanic rocks of the Bay of Bengal. Slowly, the steady filling up of the proto Bay of Bengal region led to the formation of a new landmass, which now constitutes most part of the Bangladesh territory.
The study has come up with the theory of an ancient ocean floor hidden under Bangladesh after research focused on understanding the tectonic evolution of the Bay of Bengal and Bangladesh. It involved scientists from the Centre for Earth, Ocean and Atmospheric Science (CEOAS), at the University of Hyderabad, the DST-INSPIRE faculty, National Institute of Oceanography (NIO), the Oil and Natural Gas Corporation (ONGC) and Rice University, Houston and others. The findings have been published in the latest issue of Current.
Researchers delved into the geological break-up of continents and the drifting of landmasses from the ancient Gondwanaland to form many of the present-day known continents and mountains, including the Himalayas. Their focus was on the proto Bay of Bengal region and the gradual formation of most of the Bangladesh territory over the ancient ocean floor. Their work suggested that oceanic rocks were accredited by the seafloor spreading up to Kolkata and towards the north up to the Rajmahal–Sylhet line, close to the Shillong Plateau. The presence of continental slivers in global oceans either completely buried under the sediment or remaining as islands was known, but that oceanic rocks existed beneath the landmass has been identified for the first time. Theories based on geological studies have shown how the Himalayas were formed as a result of the collision between the Indian Plate and the Eurasian Plate.