Tight coupling between the cyclicity of deep-water systems and rising-then-flat shelf-edge pairs along the submarine segment of the Qiongdongnan sediment-routing system

Abstract

On the basis of shelf-edge (SE) trajectory analysis, the present study demonstrates the tight coupling between the cyclicity of deep-water systems and contemporaneous SE trajectories with a paired rising-then-flat trajectory tendency (termed “SE pairs”) along the submarine segment of the mid-Pleistocene Qiongdongnan sediment-routing system, contributing to a better understanding of how to predict internal architecture and stacking patterns of deep-water systems. At the outlying deep-water reaches of the mid-Pleistocene Qiongdongnan sediment-routing system, Qiongdongnan deep-water systems are shown to have grown in a cyclic fashion that is stratigraphically manifested as the underlying mass-transport deposits (MTDs) systematically capped by submarine channels or sheet-like turbidites (i.e., MTD-channel and MTD-turbidite cycles, respectively). At the SE staging areas of the mid-Pleistocene Qiongdongnan sediment-routing system, Qiongdongnan shelf edges (SEs) have grown in a paired rising-then-flat fashion. The lower stratigraphic fill level of Qiongdongnan deep-water sedimentation cycles correlates to rising SE trajectories, during which the far shoreline to SE proximity (i.e., the long shoreline to SE distance of tens of kilometers) coupled to positive shelf accommodation [represented by positive SE trajectory angles () of 4.38° to 10.45°] most likely promoted passive sediment-transport agents and resultant MTDs. The upper stratigraphic fill level of mid-Pleistocene Qiongdongnan sedimentation cycles, in contrast, corresponds to flat SE trajectories, during which the close shoreline to SE proximity (i.e., the short shoreline to SE distance of < 5 km) coupled to negative shelf accommodation (represented by of –0.17° to –1.32°), in contrast, favored active sediment-transport agents and resultant submarine channels or sheet-like turbidites.

Relative sea‐level control on the building of two distinct shelf‐margin clinothems on the late‐Quaternary Pearl River margin: Insights from numerical stratigraphic forward modelling

“…Those values are typical of modern large‐sized fluvial systems (Milliman & Farnsworth, 2011), as shown in Figure S2. Furthermore, these values generate similar stratal geometries to those documented in seismic profiles of our previous studies (Gong et al, 2018; Gong, Qi, et al, 2019; Qi et al, 2022).…”

“…Using high‐resolution seismic data, Gong et al (2018), Gong, Qi et al (2019) and Qi et al (2022) mapped the detailed anatomy for SQ3 and SQ4. The anatomy suggested that on the whole Pearl River margin the SQ3 and SQ4 clinothems present significant differences, each of which has a distinct shelf edge trajectory and a given style of deep‐water deposition (Figure 2 and Figure S1).…”

“…Nevertheless, relative sea‐level changes are still considered to be the primary driving mechanism for the growth of shelf‐margin clinothems, especially on those margins with shelf characteristics of great widths and gentle gradients (Catuneanu et al, 2009; Helland‐Hansen & Hampson, 2009). The linkages among changes of relative sea level, growths of shelf edges, and the delivery of terrestrial sediments into the deep‐water settings have been the subject of increasingly intense study in recent years (Gong, Qi, et al, 2019; Posamentier et al, 2019; Zhang et al, 2017). However, most of these works were conducted over a relatively large time scale (1 My or more), which only emphasized the long‐term shelf‐margin evolution; growth of individual clinothems, the basic building blocks of stratigraphic sequences, over relatively smaller time scales of several 100 ky is less studied (Catuneanu, 2019; Magyar et al, 2019).…”

Delta‐to‐fan source‐to‐sink coupling as a fundamental control on the delivery of coarse clastics to deepwater: Insights from stratigraphic forward modelling

“…The third condition would be to have Pearl River feeder channels eating their way back to the prodelta reaches of lowstand deltas, in front of which small deep-water fans are imaged as moderate to high RMS lobes (Figure 11). Previous studies also highlighted the importance of shoreline to shelf-edge proximity in the delivery of fluvialdeltaic sediments to deepwater (Gong et al, 2019;Pellegrini et al, 2018;Sweet et al, 2020).…”

Topset-to-forest rollover trajectories as reliable predictors of sediment-volume partitioning into deep-lake areas

“…Trajectory analysis, a sequence stratigraphic tool originally developed by Helland-Hansen and Martinsen (1996) for describing shoreline movements, is considered as a significant advancement in the field of sequence stratigraphy and basin analysis (Catuneanu et al 2009(Catuneanu et al , 2011Helland-Hansen and Hampson 2009;Henriksen et al 2009;Gong et al 2015). Shelf edges in marine basins are defined as an important zone of slope gradient changes, which separates Edited by Jie Hao and Chun-Yan Tang a flat-lying shelf (i.e., topset domain) dominated by waves and shelf currents from the steeper slope (i.e., forest domain) and gentle basin-floor reaches (i.e., bottomset domain) dominated by sediment gravity-flow processes (i.e., Helland-Hansen and Hampson 2009;Henriksen et al 2009;Wild et al 2009;Jones et al 2013;Laugier and Plink-Björklund 2016;Gong et al 2019a). Topset-to-forest rollover points in lacustrine basins are defined as the gradient changes at the passages at the passage between topsets and forests (i.e., Patruno and Helland-Hansen 2018;Gamberi et al, 2020;Trincardi et al 2020).…”