Sedimentary and paleoceanographic responses to the South China Sea basin evolution

Author(s): Jian Zhimin; Liu Zhifei; Jin Haiyan; Larsen, Hans Christian; Alvarez Zarikian, Carlos A.; Stock, Joann M.; Sun Zhen; Klaus, Adam
International Ocean Discovery Program, Expedition 367 Scientists
Author Affiliation(s): Primary:
Tongji University, Laboratory of Marine Geology, Shanghai, China
Geological Survey of Denmark and Greenland, Denmark
Texas A&M University, United States
California Institute of Technology, United States
Chinese Academy of Sciences, South China Sea Institute of Oceanology, China
Volume Title: AGU 2017 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2017; American Geophysical Union 2017 fall meeting, New Orleans, LA, Dec. 11-15, 2017. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: As the largest marginal sea of the western Pacific, the South China Sea (SCS) has experienced a complete Wilson cycle, which had inevitably exerted a profound impact on the sedimentary environment and ocean circulation. Based on the results of four ODP/IODP expeditions to the SCS since 1999, together with other research data in this region, this study aims to explore the sedimentary and paleoceanographic responses to the tectonic events and basin evolution in the SCS. The early history of the SCS from land to deep sea was revealed by foraminiferal fauna: (1) The SCS evolved from continental shelf to an upper bathyal environment around the Oligocene/Eocene boundary, and significantly deepened at the turn of Oligocene/Miocene; (2) The early Oligocene SCS was deep but its shelf was narrow, evidenced by the Para-Tethys type deep-sea agglutinated benthic foraminifers and abundant transported shallow-water species at ODP Site 1148. Along with the SCS basin formation and the development of this semi-closed basin, the deep-sea benthic foraminiferal δ13C decreased when the Antarctic ice sheet began to reestablish at ∼14 Ma, the Indonesian Seaway and the southern SCS deep-water channel were closed at ∼10 Ma, the Luzon arc collided with Taiwan at ∼6.5 Ma, and the Bashi Strait was restricted at 1.2 Ma. Nd isotopes of shark teeth at ODP Site 1148 also support these inferences. An early to middle Miocene succession of red clay was found at all sites deeper than 3500 m water depth, which may be correlated to a basin-wide event related to deep circulation of oxygenated water from the western Pacific. After the earliest late Miocene carbonate crash, the red clay disappeared while the large carbonate platforms were drowned and remarkably shrank in the SCS. Late Miocene sediments display a succession of hemi-pelagic and turbidite deposits, indicating that the deep basin entered its modern state below the CCD. Frequent turbidites ended when Pliocene growth of deep-sea manganese-nodules reoccurred in the SCS. The data show that the SCS can serve as a natural laboratory to study the relationship between paleoceanographic changes and tectonic events.
Year of Publication: 2017
Research Program: ODP Ocean Drilling Program
Key Words: 16 Structural Geology; Basin analysis; Leg 184; North Pacific; Northwest Pacific; ODP Site 1148; Ocean Drilling Program; Pacific Ocean; Paleo-oceanography; South China Sea; Tectonics; West Pacific; Wilson cycle
Coordinates: N185010 N185010 E1163356 E1163356
Record ID: 2018082072
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