loading page

REE and Neodymium isotope distribution in the northern South China Sea: particulate dissolution versus water mass mixing
  • +6
  • Qiong Wu,
  • Zhifei Lliu,
  • Christophe Colin,
  • Eric Douville,
  • Yulong Zhao,
  • Arnaud Dapoigny,
  • Louise Bordier,
  • Yi Huang,
  • Pengfei Ma
Qiong Wu
College of Oceanography, Hohai University

Corresponding Author:[email protected]

Author Profile
Zhifei Lliu
State Key Laboratory of Marine Geology, Tongji University
Author Profile
Christophe Colin
Université Paris-Saclay
Author Profile
Eric Douville
LSCE Gif/Yvette
Author Profile
Yulong Zhao
Tongji University
Author Profile
Arnaud Dapoigny
Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL
Author Profile
Louise Bordier
Laboratoire des Sciences du Climat et de l'Environnement (LSCE/IPSL), UMR 8212 CNRS-CEA-UVSQ, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France.
Author Profile
Yi Huang
Université Paris-Saclay, CNRS, GEOPS
Author Profile
Pengfei Ma
Tongji University
Author Profile

Abstract

Dissolved rare earth elements (REE) and neodymium isotopic compositions (εNd) were intensively used to evaluate water mass mixing and lithogenic inputs in oceans. The South China Sea (SCS) is the largest marginal sea and a key region for reconstructing past hydrological changes in the West Pacific; however, its REE and εNd distribution are still not well established. This study investigated dissolved REE concentration and εNd distribution at four water stations in the northern and central SCS to better constrain the εNd distribution and REE cycle in the SCS. The results show relatively high concentrations of REE in surface seawater due to the terrigenous inputs. Seasonal variability in the middle REE enrichment is observed, suggesting a controlling role of the lateral mixing of water masses in the REE fractionation. The decreased REE concentrations in bottom water are mainly attributed to the re-suspended particle scavenging. Surface seawater εNd varies from -2.8±0.3 to -6.7±0.3, implying a significant modification due to riverine inputs. The intermediate water is characterized by a slightly negative εNd compared to the North Pacific Intermediate Water (NPIW) suggesting a vertical mixing between the intermediate and deep water within the SCS. εNd of deep water shows a narrow range from -3.4±0.3 to -4.2±0.3 (mean value of ~-3.8), supporting the presence of Pacific Deep Water (PDW) in the deep SCS basins nowadays. εNd of deep water in the SCS behaves conservatively along its pathway from the West Pacific to the SCS even though particle scavenging occurs in bottom water.