How did the world?s largest submarine fan in the Bay of Bengal grow and evolve at the subfan scale?

Three individual subfan-growth cycles shown to stack up over time to form the Bengal Fan were recognized. Each of them underwent the following three main evolutionary stages. Stage 1, initial channel incision and amalgamation, was responsible for forming channel-complex sets (CCSs) with lateral trajectories and concomitant amalgamation with low aggradation. Stage 2, vertical channel aggradation and the resultant creation of intrachannel lows, was responsible for generating CCSs with vertical trajectories and concomitant organized stacking with high aggradation. Stage 3, channel avulsion and concomitant upstream propagation of lobes and crevasse splays, was responsible for developing crevasse splays and lobes. These three evolutionary stages constitute a single subfan-growth cycle (i.e., an individual single channel levee-lobe system). An abrupt shift of the channel levee position separates one subfan-growth cycle from the next. Different subfan-growth cycles stacked up over time gave rise to the world's largest submarine fan in the Bay of Bengal. The pinch-out of lobes and splays onto levees because of the channel avulsion during subfan evolutionary stage 3 created stratigraphiconlap traps with the potential for large hydrocarbon accumulations.

Automated summary

Three individual subfan-growth cycles are recognized to form the Bengal Fan over time, each undergoing three main evolutionary stages: channel incision and amalgamation, vertical channel aggradation, and channel avulsion. These stages contribute to the development of a single channel levee-lobe system. The pinch-out of lobes and splays onto levees creates stratigraphic onlap traps with potential for large hydrocarbon accumulations.