Geochemical and Nd isotopic investigations of sediments from the South China Sea

Secular variations in geochemistry and Nd isotopic data have been documented in sediment samples at ODP Site 1148 in the South China Sea. Major and trace elements show significant changes at ca. 29.5 Ma and 26-23 Ma, whereas epsilon-Nd values show a single change at ca. 26-23 Ma. Increases in Al/Ti, Al/K, Rb/Sr, and La/Lu ratios and a decrease in the Th/La ratio of the sediments beginning at 29.5 Ma are consistent with more intense chemical weathering in the source region. The abrupt change in Nd isotopes and geochemistry at ca. 26-23 Ma coincides with a major discontinuity in the sedimentology and physical properties of the sediments, implying a drastic change in sedimentary provenance and environment at the drill site. Comparison of the Nd isotopes of sediments from major rivers flowing into the South China Sea suggests that pre-27 Ma sediments were dominantly derived from a southwestern provenance (Indochina-Sunda Shelf and possibly northwestern Borneo), whereas post-23 Ma sediments were derived from a northern provenance (South China). This change in provenance from southwest to north was largely caused by ridge jumping during seafloor spreading of the South China Sea, associated with a southwestward expansion of the ocean basin crust and a global rise in sea level. Thus, the geochemical and Nd isotopic changes in the sediments at ODP Site 1148 are interpreted as a response to a major plate reorganization in SE Asia at ca. 25 Ma.

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Cite this as

Li, Xian-hua, Wei, Gangjian, Shao, Lei, Liu, Ying, Liang, Xirong, Jian, Zhimin, Sun, Min, Wang, Pinxian (2003). Dataset: Geochemical and Nd isotopic investigations of sediments from the South China Sea. https://doi.org/10.1594/PANGAEA.713166

DOI retrieved: 2003

Additional Info

Field Value
Imported on November 29, 2024
Last update November 29, 2024
License CC-BY-3.0
Source https://doi.org/10.1594/PANGAEA.713166
Author Li, Xian-hua
Given Name Xian-hua
Family Name Li
More Authors
Wei, Gangjian
Shao, Lei
Liu, Ying
Liang, Xirong
Jian, Zhimin
Sun, Min
Wang, Pinxian
Source Creation 2003
Publication Year 2003
Resource Type application/zip - filename: Li_2003
Subject Areas
Name: Geophysics

Related Identifiers
Title: Geochemical and Nd isotopic variations in sediments of the South China Sea: a response to Cenozoic tectonism in SE Asia
Identifier: https://doi.org/10.1016/S0012-821X(03)00229-2
Type: DOI
Relation: IsSupplementTo
Year: 2003
Source: Earth and Planetary Science Letters
Authors: Li Xian-hua , Wei Gangjian , Shao Lei , Liu Ying , Liang Xirong , Jian Zhimin , Sun Min , Wang Pinxian .