Sediment transfer from shelf to deepwater slope: How does it happen?

Abstract

The processes that transport sediment from the coastline to the shelf edge are key components of the sedimentary source-to-sink system, determining basin-margin building, deepwater deposition, organic-material accumulation, and the long-term carbon cycle. Research on shelf sediment transport has been aided recently by advances in modeling and marine technology. In this study we provide a much needed review of up-to-date findings on how sediment moves from the outer shelf onto the upper slope, and we summarize four dominant shelf-to-slope drivers: 1) river currents, 2) reworking storm waves and longshore currents, 3) strong tidal currents supplementing river outflow, and 4) small-scale to very large-scale gravity collapse of the shelf-edge area.

Highstand sublacustrine fans: The role of a sudden increase in sediment supply

“…Meanwhile, it is believed that hyperpycnal flow in marine basins may only transport fine‐grained sediment across the shelf and accumulate in either shelf or basin floor (Pattison et al, 2007; Petter & Steel, 2006; Steel et al, 2016; Talling, 2014), although controversial remains (Mutti et al, 2003; Zavala et al, 2021). Therefore, highstand fans with relatively coarse‐grained sediments in marine basins are mainly caused by sediment failure of delta front with sufficient sediment supply in narrow shelf (Carvajal & Steel, 2006; Covault et al, 2007; Covault & Graham, 2010; Gan et al, 2022).…”

“…Source to sink investigation of the subaqueous systems is another route to reveal the formation of hyperpycnal flows (Covault et al, 2011; Gong et al, 2019, 2021; Turmel et al, 2015). A sudden increase in sediment supply may also be the main reason for highstand fans caused by hyperpycnal flows in marine basins (Gan et al, 2022; Pattison, 2005; Pattison et al, 2007; Steel et al, 2016, 2018). Future works need to assess these hypotheses to predict highstand fans' development (Gan et al, 2022).…”

“…A sudden increase in sediment supply may also be the main reason for highstand fans caused by hyperpycnal flows in marine basins (Gan et al, 2022;Pattison, 2005;Pattison et al, 2007;Steel et al, 2016Steel et al, , 2018. Future works need to assess these hypotheses to predict highstand fans' development (Gan et al, 2022).…”

“…The narrow shelf width and high sediment supply in marine basins are most favourable to the development of highstand submarine fans (Covault et al, 2007;Covault & Graham, 2010;Steel et al, 2016;Zhang et al, 2017Zhang et al, , 2019. Some studies indicate that hyperpycnal flow is common in highstand fans (Covault et al, 2010;Gan et al, 2022;Gong et al, 2019;Steel et al, 2016). However, as sediment gravity-flow may be triggered by different initiation processes (e.g.…”

“…sediment failure, hyperpycnal flow, storm resuspension) (Bailey et al, 2021; Liu et al, 2020; Piper & Normark, 2009; Talling, 2014; Yang et al, 2020; Zavala & Arcuri, 2016), and can be recognised from their deposits (e.g. intrabasinal sediment gravity flow deposits dominated by classical turbidites, mass transport complexes and slump‐related deposits, while extrabasinal sediment gravity flow deposits dominated by inverse‐then normal‐graded sandstone beds, climbing ripples, thin laminae rich in plant debris) (Yang et al, 2020; Zavala & Arcuri, 2016), it is unclear if particular initiation processes and flow types are more common in highstand fans (Catuneanu, 2020; Cosgrove et al, 2020; Gan et al, 2022; Liu et al, 2020). Lacustrine basins are characterised by narrow shelf width and sufficient sediment supply because they are closer to the source area than marine basins (Gong et al, 2019; Katz, 2001; Katz & Liu, 1998; Xian, Wang, Liu, et al, 2018; Yang et al, 2019, 2020).…”