Provenance and dispersal patterns of sediments on the continental shelf of northern South China Sea: Evidence from detrital zircon geochronology

Relict and Modern Sediments on the Continental Shelf of the Northern South China Sea: A Reconsideration

“…The sediments on the eastern NSSCS are additionally affected by the KI that drives the southwestward movement of seawater and the transport of the suspended sediments along the northern slope of the SCS (Fang et al., 2015; Liu et al., 2016; Webster & Peter, 1994). Thus, the spatial heterogeneity for the NSCS sediments is likely the collective result of different sedimentary provenances, transportation, discharge and hydrodynamic processes (Jia et al., 2023). Their deposited nature and spatial pattern varied significantly from the latest Pleistocene to the early Holocene.…”

“…Thus, the sediments in the Area I Channel are mainly sourced from the Pearl River fluvial system, and the hydraulic sorting during sediment transportation is responsible for the development of heavy mineral deposits. Alongside the coarser zone in Area I, fine‐grained suspended particles discharged from the rivers are carried on the continental shelf by the river plume and coastal currents, at which they are transported away from the estuary (Jia et al., 2023). Due to the rapid decrease in flow velocity across the Area I Channel along with the changes in salinity and other properties of the seawater, the fine‐grained sediments are likely deposited at the adjacent areas as the bed load mixes with the flocculated materials (Papista et al., 2011).…”

“…It has also been challenged for the view that “relict sediments” are extensively exposed on the NSSCS sea‐floor, as suggested by Emery (1968) (e.g., Luan et al., 2010; McManus, 1975; Shen et al., 2021; Swift et al., 1971). Others suggested that the surface sediments were reworked in the modern environment and thus might not be categorized as relict sediments (Huh et al., 2011; Jia et al., 2023; Li et al., 1991; Swift et al., 1971; L. Zhong et al., 2017; Y. Zhong et al., 2017). A line of evidence shows that the relict sediments are distinct from the alongshore‐ and seaward‐fining modern sands supplied from the adjacent estuaries, beaches and cliffs (e.g., Emery, 1968; Swift et al., 1971); thus, the surface sediments in the NSSCS outer shelf need to be revisited, which is the focus of this paper.…”

“…However, less attention has been paid to the relict sediments despite a significant body of research has been conducted on the sediment supply and Holocene environment during marine resource surveys of the NSSCS over the last five decades (e.g., Cao et al., 2019; Fang et al., 2015; J. Liu et al., 2010; Z. Liu et al., 2010; Tamburini et al., 2003; Tan & Sun, 1988; Wehausen & Brumsack, 2002; Yang et al., 2005; Zhao et al., 2015; L. Zhong et al., 2017; Y. Zhong et al., 2017). The NSSCS is generally subdivided into two hydrographic units of inner and outer shelves across a water depth of −80 m (Figure 1; Jia et al., 2023; Wang et al., 2022; L. Zhong et al., 2017). In the NSSCS inner shelf, the surface sediments were deposited seaward in the order of sand, silt, and clay in response to modern wave dynamics (e.g., Wang et al., 1986).…”

“…Liu et al, 2010;Tamburini et al, 2003;Tan & Sun, 1988;Wehausen & Brumsack, 2002;Yang et al, 2005;Zhao et al, 2015;. The NSSCS is generally subdivided into two hydrographic units of inner and outer shelves across a water depth of −80 m (Figure 1; Jia et al, 2023;Wang et al, 2022;. In the NSSCS inner shelf, the surface sediments were deposited seaward in the order of sand, silt, and clay in response to modern wave dynamics (e.g., Wang et al, 1986).…”