DOI: 10.1016/j.epsl.2018.09.013
Scopus记录号: 2-s2.0-85054193037
论文题名: A 10-fold decline in the deep Eastern Mediterranean thermohaline overturning circulation during the last interglacial period
作者: Andersen M.B. ; Matthews A. ; Vance D. ; Bar-Matthews M. ; Archer C. ; de Souza G.F.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 503 起始页码: 58
结束页码: 67
语种: 英语
英文关键词: last interglacial
; Mediterranean
; molybdenum isotopes
; sapropels
; uranium isotopes
Scopus关键词: Nuclear fuels
; Last interglacial
; Mediterranean
; Molybdenum isotopes
; sapropels
; Uranium isotopes
; Isotopes
英文摘要: Present-day Mediterranean deep-waters are well oxygenated, but the episodic formation of organic-rich sediments (sapropels) indicates that this pattern was frequently perturbed in the past. Both high export productivity and disruption of the thermohaline circulation, leading to reduced deep-water ventilation, have been proposed to account for sapropel deposition and anoxia. The last interglacial sapropel S5 is considered one of the most strongly developed. Here, we apply the redox-sensitive Mo and U (elemental and isotope) systems to quantify the intensity of anoxic deep-water conditions in the Eastern Mediterranean Sea from ODP core 967 (2550 mbsl). Both U and Mo show strong authigenic enrichment, coupled to progressive increase in δ98Moauth (+1.2–1.8‰ to +2.0–2.3‰) and decrease in δ238Uauth (+0.10‰ to −0.15‰) from the beginning to the end of S5, suggesting increasing water column euxinia and removal fluxes of Mo and U. Based on modern euxinic basins, we show that sedimentary δ238Uauth can be used to derive estimates of water column U depletion and, ultimately, deep-water renewal rates. These principles are first tested on the modern Black Sea, which yields calculated deep-water renewal times of 830+690/−500 yrs, in good agreement with independent estimates. Applying these principles to the end of S5 suggests bottom-water U depletion of ∼50% and deep-water renewal times of 1030+820/−520 yrs. The significantly slower deep-water renewal rates in the Eastern Mediterranean Sea compared to today (∼100 yrs) would have played an important role in the formation of sapropel S5 and are consistent with the proposed suppression of overturning during the last interglacial, due to increased stratification resulting from higher riverine freshwater input under enhanced monsoon forcing. © 2018 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/109623
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Cardiff University, School of Earth & Ocean Sciences, Park Place, Cardiff, CF10 3AT, United Kingdom; ETH Zürich, Institute of Geochemistry and Petrology, Department of Earth Sciences, Clausiusstrasse 25, Zurich, 8092, Switzerland; Institute of Earth Sciences, Hebrew University of Jerusalem, Jerusalem, 91904, Israel; Geological Survey of Israel, Jerusalem, 95501, Israel
Recommended Citation:
Andersen M.B.,Matthews A.,Vance D.,et al. A 10-fold decline in the deep Eastern Mediterranean thermohaline overturning circulation during the last interglacial period[J]. Earth and Planetary Science Letters,2018-01-01,503