Late Quaternary climatic forcing on the terrigenous supply in the northern South China Sea; input from magnetic studies

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doi: 10.1016/j.epsl.2017.04.047
Author(s): Chen Quan; Kissel, Catherine; Liu Zhifei
Author Affiliation(s): Primary:
Tongji University, State Key Laboratory of Marine Geology, Shanghai, China
Other:
Université Paris-Saclay, France
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, Vol.471, p.160-171. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. Includes appendix. 50 refs.; illus., incl. sketch map
Summary: The detrital component of marine sediment is a powerful recorder of paleoenvironmental changes in a marginal sea such as the South China Sea. This is in particular valid for the magnetic fraction that is one of the key parameters for paleoenvironmental studies in the South China Sea, although poorly used so far. We report here on the analysis of the magnetic properties of a 50 m-long sedimentary sequence retrieved from the northern South China Sea, on the continental slope off the Pearl River mouth. Magnetic minerals with different coercivities (magnetite, pyrrhotite, and hematite) are mixed. The variations in relative content of these magnetic minerals illustrate influences of various external forcing mechanisms at different timescales. The pyrrhotite content exhibits a long-term increase, which is also observed in illite + chlorite content, indicating a continuous enhancement of supply from Taiwan most likely related to active Taiwan orogeny. Glacial-interglacial fluctuations are characterized by more magnetite and pyrrhotite with coarser silt and magnetic grains during glacials than interglacials. This is attributed to sea-level changes with the enormous continental shelf exposed during glacials, in turn affecting the sediment transport distance and pathway. On a shorter timescale, larger hematite inputs in fine-grained sediments coincide with precession minima. We suggest that this periodic hematite supply change is related to the eolian dust deposited at the studied site in addition to the fluvial and oceanic transported materials.
Year of Publication: 2017
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Asia; Cenozoic; Clastic sediments; Clay minerals; Climate forcing; Continental shelf; Cores; Far East; Glacial environment; Grain size; Hematite; Interglacial environment; Leg 184; Magnetic minerals; Magnetic properties; Magnetite; Marine sediments; Monsoons; North Pacific; Northwest Pacific; ODP Site 1146; Ocean Drilling Program; Oxides; Pacific Ocean; Paleoenvironment; Pyrrhotite; Quaternary; Sea-level changes; Sediment transport; Sediments; Sheet silicates; Silicates; Silt; South China Sea; Sulfides; Taiwan; Taiwan Orogeny; Terrigenous materials; Transport; Upper Quaternary; West Pacific
Coordinates: N191700 N191700 E1161500 E1161500
Record ID: 2017056504
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands