Paleoceanography of the mid-Pleistocene South China Sea

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doi: 10.1016/j.quascirev.2008.02.007
Author(s): Li Qianyu; Wang Pinxian; Zhao Quanhong; Tian Jun; Cheng Xinrong; Jian Zhimin; Zhong Guangfa; Chen, Muhong
Author Affiliation(s): Primary:
Tongji University, State Key Laboratory of Marine Geology, Shanghai, China
Other:
Chinese Academy of Sciences, South China Sea Institute of Oceanology, China
Volume Title: Quaternary Science Reviews
Source: Quaternary Science Reviews, 27(11-12), p.1217-1233. Publisher: Elsevier, International. ISSN: 0277-3791
Note: In English. 71 refs.; illus., incl. 1 table, sketch maps
Summary: High-frequency fluctuations in paleoenvironmental proxies from the South China Sea, including stable isotopes and abundance of planktonic foraminifers, nannofossils, radiolarians, and palynomorphs, reveal a dynamic local response to the stepwise development of the mid-Pleistocene climate transition (MPT). These proxies indicate a dramatic drop in sea surface temperature (SST) at about 900 ka, the first largest SST decrease in the region during the Quaternary. Estimated winter SST declined from 24-25°C to 17-18°C in the northern and from 26-27°C to 23-24°C in the southern South China Sea. Subsequent changes in the thermocline depth and faunal-floral turnovers imply a period of about 300 ka in the final stage of the MPT. Winter monsoons increased at ∼900 ka and reached a maximum strength toward the end of the MPT when summer monsoons also strengthened in interglacials. As a result, thermal gradient between the northern and southern South China Sea increased substantially, with stronger winter monsoon influence in the north and warm and saline conditions in the south especially during glacial periods. These N-S paleoceanographic contrasts indicate an initial establishment of the modern-styled semi-enclosed South China Sea about 900 ka ago when passages in the south started to become completely exposed during glacial lowstands. Coupled with deep water cooling and ventilation, uplift of the sill depth in the Bashi Strait to near the present-2400 m during this period caused sudden decline and extinction of Pacific Deep Water benthic foraminifers in the isolated deep sea basin. Together with data from the oceanic western Pacific, these results further imply a considerable weakening of the western Pacific warm pool during MIS 23-22 and in subsequent glacial periods. While the MPT may have invoked high latitude processes especially an increased ice volume, tropical processes more likely have facilitated the restoration of heat and energy to the western Pacific in each interglacial rebound. Planktonic δ13C maxima on eccentricity periocities leading major cooling events during the Quaternary indicate the important role of global carbon reservoir changes due to low as well as high latitude processes in past climate change. Abstract Copyright (2008) Elsevier, B.V.
Year of Publication: 2008
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Algae; C-13/C-12; Carbon; Cenozoic; Climate change; Core SO95-17957-2; Diatoms; Foraminifera; Glacial rebound; Glaciation; Invertebrata; Isostatic rebound; Isotope ratios; Isotopes; Leg 184; Microfossils; Middle Pleistocene; Miospores; Monsoons; Nannofossils; North Pacific; Northwest Pacific; O-18/O-16; ODP Site 1143; ODP Site 1144; ODP Site 1146; ODP Site 1148; Ocean Drilling Program; Oxygen; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Paleoenvironment; Paleosalinity; Paleotemperature; Palynomorphs; Plantae; Pleistocene; Pollen; Protista; Quaternary; Radiolaria; Sea-surface temperature; South China Sea; Spores; Stable isotopes; West Pacific
Coordinates: N092200 N092200 E1131700 E1131700
N200300 N200300 E1172500 E1172500
N192700 N192700 E1161600 E1161600
N185010 N185010 E1163357 E1163357
Record ID: 2010044777
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands