Submarine fans at all sea-level stands: Tectono-morphologic and climatic controls on terrigenous sediment delivery to the deep sea

Early models of stratigraphic sequence development across continental margins predicted terrigenous sediment delivery to the deep sea principally during periods of sea-level fall and lowstand. However, subsequent models acknowledged caveats to these early predictions. We employ a global database of millennial-scale continental-margin deep-sea deposition rates, activities of canyon-channel systems, and episodes of submarine-fan growth since 35 ka to assess the timing of terrigenous sediment delivery to the deep sea. As predicted by the early models, the majority of continental-margin deep-sea deposition occurred during periods of marine transgression and lowstand of sea level. However, deep-sea deposition is shown to have occurred at all sea-level states, and some deep-sea fans predominantly grew during periods of sea-level highstand. Terrigenous sediment delivery to the deep sea depends on factors such as tectono-morphologic character of the margin (e.g., narrow shelves) and climatic forcings (e.g., subglacial meltwater and monsoonal pulses). A fundamental understanding of the tectonic and climatic forcings inherent to a continental margin and its terrestrial sediment source area is essential to accurately predict timing and magnitude of deep-sea deposition and place it in the context of sequence stratigraphy.