DOI: 10.1016/j.quascirev.2016.11.032
Scopus记录号: 2-s2.0-85006355127
论文题名: Authigenic Nd isotope record of North Pacific Intermediate Water formation and boundary exchange on the Bering Slope
作者: Jang K. ; Huh Y. ; Han Y.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2017
卷: 156 起始页码: 150
结束页码: 163
语种: 英语
英文关键词: Authigenic
; Bering Sea
; Brine
; Neodymium
; NPIW
; Seesaw
; Ventilation
Scopus关键词: Algae
; Brines
; Ice
; Isotopes
; Manganese
; Manganese removal (water treatment)
; Neodymium
; Phytoplankton
; Sea ice
; Ventilation
; Authigenic
; Bering sea
; Global ocean circulation
; Nd isotopic compositions
; North Atlantic Deep Water
; NPIW
; Seawater compositions
; Seesaw
; Sediments
; abundance
; benthic foraminifera
; bottom water
; brine
; carbonate
; climate
; continental margin
; global ocean
; isotopic composition
; neodymium isotope
; North Atlantic Deep Water
; oceanic circulation
; sea ice
; seawater
; Atlantic Ocean
; Atlantic Ocean (North)
; Atlantic Ocean (South)
; Bering Sea
; Bering Strait
; Pacific Ocean
; Pacific Ocean (North)
; Bacillariophyta
; Bulimina
; Foraminifera
英文摘要: The Bering Sea is a potential location for the formation of the North Pacific Intermediate Water (NPIW), which drives the global ocean circulation as a counterpart to the North Atlantic Deep Water (NADW). To evaluate the NPIW-NADW seesaw hypothesis, we reconstructed the long-term variation of the bottom water Nd isotopic composition at site U1345 on the Bering Slope by extracting authigenic Fe-Mn oxyhydroxide from bulk sediments. We examined six different extractions in order to ensure that authentic seawater composition is recovered. For Bering Slope sediments whose typical carbonate content is less than 5% (average 2%), the most reliable results are obtained if the decarbonation step is omitted and a low reagent-to-sediment ratio is adopted. The reconstructed authigenic εNd record for the last 520 kyr exhibits large temporal variations depending on whether the NPIW formation or the boundary exchange process is dominant. Periods of radiogenic εNd can be attributed to NPIW formation triggered by brine rejection, as evidenced by the difference in δ18O of benthic foraminifera between sites (Δδ18Obf), high % sea-ice related diatoms, and low abundance of Bulimina aff. Exilis (low-oxygen deep fauna). Diminished supply of unradiogenic Nd from boundary exchange seems to intensify these radiogenic peaks. On the other hand, the unradiogenic εNd intervals can be attributed to stagnant bottom water conditions, as can be deduced from the Δδ18Obf values, low % sea-ice related diatoms, abundant B. aff. Exilis, and laminations. When there is no NPIW formation, the continental margin sediments are exposed to boundary exchange for a longer period of time, leading to release of unradiogenic Nd. The mid-MIS 6 and mid-MIS 5 are exceptions in that NPIW formation occurred yet the εNd compositions are unradiogenic. NPIW formation and cold climate (closed Bering Strait) are not always correlated. Comparison against εNd records of the South Atlantic suggests only an ambiguous NPIW-NADW seesaw for the last 200 kyr. © 2016 Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59346
Appears in Collections: 过去全球变化的重建
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作者单位: School of Earth and Environmental Sciences, Seoul National University, Seoul, South Korea; Division of Polar Paleoenvironment, Korea Polar Research Institute, Incheon, South Korea
Recommended Citation:
Jang K.,Huh Y.,Han Y.. Authigenic Nd isotope record of North Pacific Intermediate Water formation and boundary exchange on the Bering Slope[J]. Quaternary Science Reviews,2017-01-01,156