Title

Modern transport and deposition of settling particles in the northern South China Sea: Sediment trap evidence adjacent to Xisha Trough

Document Type

Article

Publication Date

11-1-2014

Abstract

© 2014 Elsevier Ltd. Studies on modern sediment transport and deposition, especially studies analyzing settling particles collected with sediment traps, have rarely been carried out in the northern South China Sea. Using sediment trap time series data from Site XS1 (17°24.5'N, 110°55.0'E, water depth 1690m) adjacent to the Xisha Trough, variations in sediment source through time have been reconstructed. These observations include total particle flux (TPF) and current data, grain size distributions, and clay mineral compositions obtained from two sediment traps deployed in 500m and 1500m water depth, respectively. Time series records at Site XS1 changed seasonally for both sampled layers. TPF in the lower layer (426mg/m2/d) was several times that of the upper layer (113mg/m2/d) and is affected by lateral transport. However, mean grain size (Mz) of the upper layer is greater that of the lower layer (29 vs10μm) due to contributions from biogenic materials. There are no clear seasonal changes in clay mineral assemblage in either the upper or lower layers. The annual percentages of four main clay minerals were 82-83% illite, 7-9% kaolinite, 6-8% chlorite and 1-3% smectite. Taiwan was the dominant sediment source (42-74%), while sediment contributions from the Red River and Annamite Chain account for 23-53% and 0-15%, respectively. Sediment supply from Taiwan could be explained by deep water current flow, while coastal currents may aid sediment transport from the Red River and small mountainous rivers of central Vietnam.

Publication Source (Journal or Book title)

Deep-Sea Research Part I: Oceanographic Research Papers

First Page

145

Last Page

155

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