干旱区生态环境知识资源中心(Arid): Unmixing biogenic and terrigenous magnetic mineral components in red clay of the Pacific Ocean using principal component analyses of first-order reversal curve diagrams and paleoenvironmental implications

Arid

DOI	10.1186/s40623-020-01248-5
	Unmixing biogenic and terrigenous magnetic mineral components in red clay of the Pacific Ocean using principal component analyses of first-order reversal curve diagrams and paleoenvironmental implications
	Yamazaki, Toshitsugu; Fu, Wei; Shimono, Takaya; Usui, Yoichi
通讯作者	Yamazaki, T
来源期刊	EARTH PLANETS AND SPACE
EISSN	1880-5981
出版年	2020
卷号	72 期号:1
英文摘要	Red clay widely occupies the seafloor of pelagic environments in middle latitudes, and potentially preserves long paleoceanographic records. We conducted a rock-magnetic study of Pacific Ocean red clay to elucidate paleoenvironmental changes. Three piston cores from the western North Pacific Ocean and IODP Hole U1365A cores in the South Pacific Ocean were studied here. Principal component analyses applied to first-order reversal curve diagrams (FORC-PCA) reveals three magnetic components (endmembers EM1 through EM3) in a core of the western North Pacific. EM1, which represents the features of interacting single-domain (SD) and vortex states, is interpreted to be of terrigenous origin. EM2 and EM3 are carried by non-interacting SD grains with different coercivity distributions, which are interpreted to be of biogenic origin. The EM1 contribution suddenly increases upcore at a depth of similar to 2.7 m, which indicates increased eolian dust input. The age of this event is estimated to be around the Eocene-Oligocene (E/O) boundary. Transmission electron microscopy reveals that EM2 is dominated by magnetofossils with equant octahedral morphology, while EM3 has a higher proportion of bullet-shaped magnetofossils. An increased EM3 contribution from similar to 6.7 to 8.2 m suggests that the sediments were in the oxic-anoxic transition zone (OATZ), although the core is oxidized in its entire depth now. The chemical conditions of OATZ may have been caused by higher biogenic productivity near the equator. FORC-PCA of Hole U1365A cores identified two EMs, terrigenous (EM1) and biogenic (EM2). The coercivity distribution of the biogenic component at Hole U1365A is similar to that of the lower coercivity biogenic component in the western North Pacific. A sudden upcore terrigenous-component increase is also evident at Hole U1365A with an estimated age around the E/O boundary. The increased terrigenous component may have been caused by the gradual tectonic drift of the sites on the lee of arid continental regions in Asia and Australia, respectively. Alternatively, the eolian increase may have been coeval in the both hemispheres and associated with the global cooling at the E/O boundary.
英文关键词	Red clay Rock magnetism FORC diagram Biogenic magnetite Eolian dust Eocene-Oligocene boundary
类型	Article
语种	英语
开放获取类型	DOAJ Gold
收录类别	SCI-E
WOS记录号	WOS:000560200000001
WOS关键词	ENVIRONMENTAL ROCK-MAGNETISM ; ORGANIC-CARBON FLUX ; NORTH PACIFIC ; DEEP-SEA ; EOLIAN DEPOSITION ; RELATIVE PALEOINTENSITY ; PELAGIC SEDIMENTS ; REMANENCE CURVES ; PARTICLE-SYSTEMS ; GRAIN-SIZE
WOS类目	Geosciences, Multidisciplinary
WOS研究方向	Geology
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/325654
作者单位	[Yamazaki, Toshitsugu; Fu, Wei] Univ Tokyo, Atmosphere & Ocean Res Inst, Kashiwa, Chiba, Japan; [Shimono, Takaya] Natl Inst Adv Ind Sci & Technol, Geol Survey Japan, Tsukuba, Ibaraki, Japan; [Usui, Yoichi] Japan Agcy Marine Earth Sci & Technol, Volcanoes & Earths Interior Res Ctr, Res Inst Marine Geodynam, Yokosuka, Kanagawa, Japan
推荐引用方式 GB/T 7714	Yamazaki, Toshitsugu,Fu, Wei,Shimono, Takaya,et al. Unmixing biogenic and terrigenous magnetic mineral components in red clay of the Pacific Ocean using principal component analyses of first-order reversal curve diagrams and paleoenvironmental implications[J],2020,72(1).
APA	Yamazaki, Toshitsugu,Fu, Wei,Shimono, Takaya,&Usui, Yoichi.(2020).Unmixing biogenic and terrigenous magnetic mineral components in red clay of the Pacific Ocean using principal component analyses of first-order reversal curve diagrams and paleoenvironmental implications.EARTH PLANETS AND SPACE,72(1).
MLA	Yamazaki, Toshitsugu,et al."Unmixing biogenic and terrigenous magnetic mineral components in red clay of the Pacific Ocean using principal component analyses of first-order reversal curve diagrams and paleoenvironmental implications".EARTH PLANETS AND SPACE 72.1(2020).