DOI: 10.1016/j.quascirev.2016.03.027
Scopus记录号: 2-s2.0-84962013332
论文题名: Authigenic 10Be/9Be ratios and 10Be-fluxes (230Thxs-normalized) in central Baffin Bay sediments during the last glacial cycle: Paleoenvironmental implications
作者: Simon Q. ; Thouveny N. ; Bourlès D.L. ; Nuttin L. ; Hillaire-Marcel C. ; St-Onge G.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2016
卷: 140 起始页码: 142
结束页码: 162
语种: 英语
英文关键词: 10Be cosmogenic nuclide
; 10Befluxes 230Thxs-normalization
; Authigenic 10Be/9Be ratios
; Baffin bay
; Freshwater flux
; Glacial dynamics
; Late quaternary
; Paleo-denudation rate
; Stratigraphic markers
Scopus关键词: Beryllium
; Dynamics
; Geomagnetism
; Glacial geology
; Isotopes
; Minerals
; Stratigraphy
; Water
; <sup>10</sup>Befluxes <sup>230</sup>Thxs-normalization
; Authigenic
; Baffin bay
; Cosmogenic nuclides
; Denudation rates
; Freshwater fluxes
; Late quaternary
; Stratigraphic markers
; Sediments
; authigenic mineral
; beryllium isotope
; concentration (composition)
; cosmogenic radionuclide
; denudation
; freshwater input
; geomagnetic field
; glacial history
; last deglaciation
; Last Glacial
; paleoclimate
; sediment core
; weathering profile
; Arctic Ocean
; Atlantic Ocean
; Atlantic Ocean (North)
; Baffin Bay [Arctic Ocean]
英文摘要: Authigenic 10Be/9Be ratios and 10Be-fluxes reconstructed using the 230Thxs normalization, proxies of the cosmogenic radionuclide 10Be production rate in the atmosphere, have been measured in a sedimentary core from Baffin Bay (North Atlantic) spanning the last 136 ka BP. The normalization applied on the exchangeable (authigenic) 10Be concentrations using the authigenic 9Be isotope and 230Thxs methods yield equivalent results strongly correlated with sedimentological parameters (grain-size and mineralogy). Lower authigenic beryllium (Be) concentrations and 10Be/9Be ratios are associated with coarse-grained carbonate-rich layers, while higher authigenic Be values are related to fine-grained felspar-rich sediments. This variability is due to: i) sediment composition control over beryllium-scavenging efficiency and, ii) glacial history that contributed to modify the 10Be concentration in Baffin Bay by input and boundary scavenging condition changes. Most paleo-denudation rates inferred from the 10Be/9Be ratio vary weakly around 220 ± 76 tons.km-2.yr-1 (0.09 ± 0.03 mm.yr-1) corresponding to relatively steady weathering fluxes over the last glacial cycle except for six brief intervals characterized by sharp increases of the denudation rate. These intervals are related to ice-surging episodes coeval with Heinrich events and the last deglaciation period. An average freshwater flux of 180.6 km3.yr-1 (0.006 Sv), consistent with recent models, has been calculated in order to sustain glacially-derived 10Be inputs into Baffin Bay. It is concluded that in such environments, the authigenic 10Be measured mainly depends on climatic effects related to the glacial dynamics, which masks the 10Be production variation modulated by geomagnetic field changes. Altogether, these results challenge the simple interpretation of 10Be-concentration variation as a proxy of Interglacial/Glacial (interstadial/stadial) cycles in Arctic and sub-Arctic regions. They rather suggest the effect of higher-frequency paleoclimatic changes and local glacial dynamics on 10Be signature. © 2016 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/59604
Appears in Collections: 过去全球变化的重建
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作者单位: CEREGE UM34, Aix-Marseille Université, CNRS, IRD, Aix en Provence, France; GEOTOP Research Center, Montréal, Canada; Institut des sciences de la mer de Rimouski (ISMER), Canada Research Chair in Marine Geology, Université du Québec à Rimouski, Canada
Recommended Citation:
Simon Q.,Thouveny N.,Bourlès D.L.,et al. Authigenic 10Be/9Be ratios and 10Be-fluxes (230Thxs-normalized) in central Baffin Bay sediments during the last glacial cycle: Paleoenvironmental implications[J]. Quaternary Science Reviews,2016-01-01,140