Clay mineral assemblages in the northern South China Sea; implications for East Asian monsoon evolution over the past 2 million years

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doi: 10.1016/S0025-3227(03)00213-5
Author(s): Liu Zhifei; Trentesaux, Alain; Clemens, Steven C.; Colin, Christophe; Wang Pinxian; Huang Baoqi; Boulay, Sébastien
Author Affiliation(s): Primary:
Tongji University, Laboratory of Marine Geology, Shanghai, China
Tongji University, China
Université de Lille I, France
Brown University, United States
Université de Paris XI, France
Volume Title: Asian monsoons and global linkages on Milankovitch and sub-Milankovitch time scales
Volume Author(s): Clemens, Steven C., editor; Wang Pixian; Prell, Warren L.
Source: Marine Geology, 201(1-3), p.133-146; Asian monsoons and global linkages on Milankovitch and sub-Milankovitch time scales, Beijing, China, May 9-11, 2001, edited by Steven C. Clemens, Wang Pixian and Warren L. Prell. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0025-3227 CODEN: MAGEA6
Note: In English. 56 refs.; illus., incl. 3 tables, sketch maps
Summary: Clay mineral assemblages at ODP Site 1146 in the northern South China Sea are used to investigate sediment source and transport processes and to evaluate the evolution of the East Asian monsoon over the past 2 Myr. Clay minerals consist mainly of illite (22-43%) and smectite (12-48%), with associated chlorite (10-30%), kaolinite (2-18%), and random mixed-layer clays (5-22%). Hydrodynamic and mineralogical studies indicate that illite and chlorite sources include Taiwan and the Yangtze River, that smectite and mixed-layer clays originate predominantly from Luzon and Indonesia, and that kaolinite is primarily derived from the Pearl River. Mineral assemblages indicate strong glacial-interglacial cyclicity, with high illite, chlorite, and kaolinite content during glacials and high smectite and mixed-layer clay content during interglacials. During interglacials, summer enhanced monsoon (southwesterly) currents transport more smectite and mixed-layer clays to Site 1146 whereas during glacials, enhanced winter monsoon (northerly) currents transport more illite and chlorite from Taiwan and the Yangtze River. The ratio (smectite+mixed layers)/(illite+chlorite) was adopted as a proxy for East Asian monsoon variability. Higher ratios indicate strengthened summer-monsoon winds and weakened winter-monsoon winds during interglacials. In contrast, lower ratios indicate a strongly intensified winter monsoon and weakened summer monsoon during glacials. Spectral analysis indicates the mineral ratio was dominantly forced by monsoon variability prior to the development of large-scale glaciation at 1.2 Myr and by both monsoon variability and the effects of changing sea level in the interval 1.2 Myr to present. Abstract Copyright (2003) Elsevier, B.V.
Year of Publication: 2003
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Asia; Cenozoic; China; Clay mineralogy; Clay minerals; Cores; Far East; Leg 184; Luzon; Marine sediments; Mineral assemblages; Monsoons; North Pacific; Northwest Pacific; ODP Site 1146; Ocean Drilling Program; Pacific Ocean; Paleoclimatology; Philippine Islands; Pleistocene; Quaternary; Reconstruction; Sediment transport; Sediments; Sheet silicates; Silicates; South China Sea; Taiwan; West Pacific; Yangtze River
Coordinates: N192724 N192724 E1161622 E1161622
Record ID: 2003074933
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands