Magnetostratigraphic and environmental implications of greigite (Fe3S4) formation from Hole U1433A of the IODP Expedition 349, South China Sea

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doi: 10.1016/j.margeo.2017.02.008
Author(s): Duan Zongqi; Liu Qingsong; Gai Congcong; Zhao Xixi
Author Affiliation(s): Primary:
Chinese Academy of Sciences, Institute of Geology and Geophysics, Beijing, China
Other:
Southern University of Science and Technology, China
Tongji University, China
Volume Title: Evolution of the deep South China Sea; Integrated IODP Expedition 349 results
Volume Author(s): Liu Zhifei, editor; Li Chunfeng; Kulhanek, Denise
Source: Evolution of the deep South China Sea; Integrated IODP Expedition 349 results, edited by Liu Zhifei, Li Chunfeng and Denise Kulhanek. Marine Geology, Vol.394, p.82-97. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0025-3227 CODEN: MAGEA6
Note: In English. 89 refs.; illus., incl. sketch map
Summary: A detailed magnetic analysis has been done on sedimentary core of the International Ocean Discovery Program (IODP) Site U1433A during Leg 349 in the South China Sea (SCS). Results show that dominant carriers of the natural remanent magnetization are greigite and (titano) magnetite. The major shift in both declination and inclination at ∼ 185 mbsf is assigned to the Matuyama-Brunhes reversal boundary (∼ 0.773 Ma). Constrained by biostratigraphic ages, variations in magnetic parameters of the core can be well correlated to the marine oxygen isotope record at glacial/interglacial cycles. Low values of concentration-dependent magnetic parameters correspond to the interglacials, and vice versa. During the interglacial periods, the dominant magnetic minerals are detrital (titano) magnetite and have relatively coarser grain sizes, while fine-grained greigites dominate the glacial periods. This indicates that during the glacials, greigite prevails at the anoxic condition with amount of terrigenous iron oxide caused by the disconnection between the SCS and the Indian Ocean and the exposure of shelf, but digenesis is suppressed at the opposite environment by the high sea level (interglacials). Thus, the preservation/sulfide process of (titano) magnetite is intimately related to the transformation of sea level changes with the monsoon-related rainfall caused by the glacial/interglacial variation.
Year of Publication: 2017
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Cenozoic; Cores; East Pacific; Equatorial Pacific; Expedition 349; Glacial environment; Greigite; IODP Site U1433; Interglacial environment; International Ocean Discovery Program; Isotope ratios; Isotopes; Leg 111; Leg 184; Magnetic declination; Magnetic inclination; Magnetization; Magnetostratigraphy; Marine sediments; Natural remanent magnetization; North Pacific; Northeast Pacific; Northwest Pacific; O-18/O-16; ODP Site 1146; ODP Site 677; Ocean Drilling Program; Oxides; Oxygen; Pacific Ocean; Paleoenvironment; Paleomagnetism; Quaternary; Remanent magnetization; Sea-level changes; Sediments; South China Sea; Stable isotopes; Sulfides; Titanomagnetite; Upper Quaternary; West Pacific
Coordinates: N125508 N125508 E1150251 E1150250
N192724 N192724 E1161622 E1161622
N011203 N011209 W0834413 W0834414
Record ID: 2018009026
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands