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Registros recuperados: 3
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Magnetic record of deglaciation using FORC-PCA, sortable-silt grain size, and magnetic excursion at 26 ka, from the Rockall Trough (NE Atlantic) ArchiMer
Channell, J. E. T.; Harrison, R. J.; Lascu, I.; Mccave, I. N.; Hibbert, F. D.; Austin, W. E. N..
Core MD04-2822 from the Rockall Trough has apparent sedimentation rates of ∼ 1 m/kyr during the last deglaciation (Termination I). Component magnetization directions indicate a magnetic excursion at 16.3 m depth in the core, corresponding to an age of 26.5 ka, implying an excursion duration of ∼350 years. Across Termination I, the mean grain size of sortable silt implies reduced bottom-current velocity in the Younger Dryas and Heinrich Stadial (HS)-1A, and increased velocities during the Bølling-Allerød warm period. Standard bulk magnetic parameters imply fining of magnetic grain size from the mid-Younger Dryas (∼12 ka) until ∼ 8 ka. First-order reversal curves (FORCs) were analyzed using ridge extraction to differentiate single domain (SD) from background...
Tipo: Text Palavras-chave: Magnetic granulometry; FORC-PCA analysis; Sortable silt; Magnetic excursion; Termination I; Rockall Trough.
Ano: 2016 URL: https://archimer.ifremer.fr/doc/00333/44456/44128.pdf
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Rapid transient changes in northeast Atlantic deep water ventilation age across Termination I ArchiMer
Skinner, Lc; Shackleton, Nj.
A sequence of accelerator mass spectrometry (AMS) C-14 dates performed on benthic and planktonic foraminifera from a northeast Atlantic deep-sea core (MD99-2334K; 37degrees480N, 10degrees10'W; 3146 m) permit the reconstruction of deep water ,,C-14 ventilation ages'' across the last deglaciation. The records from MD99-2334K have been placed on the GISP2 timescale via the synchrony of temperature changes recorded in the Greenland ice cores and in North Atlantic planktonic delta(18)O(cc) (calcite delta(18)O). On the basis of a range of estimates for past source water Delta(14)C, this permits the estimation of C-14 projection ventilation ages for comparison with benthic-planktonic C-14 age differences. Although the accurate estimation of past ventilation ages...
Tipo: Text Palavras-chave: Termination I; Ventilation age; Thermohaline circulation.
Ano: 2004 URL: https://archimer.ifremer.fr/doc/00228/33971/32339.pdf
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Millennial-scale variability of deep-water temperature and delta O-18(dw) indicating deep-water source variations in the Northeast Atlantic, 0-34 cal. ka BP ArchiMer
Skinner, Lc; Shackleton, Nj; Elderfield, H.
Paired measurements of Mg/Ca and delta(18)O(cc) (calcite delta(18)O) in benthic foraminifera from a deep-sea core recovered on the Iberian Margin (MD99-2334K; 37degrees 48'N, 10degrees10'W; 3,146 m) have been performed in parallel with planktonic delta(18)O(cc) analyses and counts of ice-rafted debris (IRD). The synchrony of temperature changes recorded in the Greenland ice cores and in North Atlantic planktonic delta(18)O(cc) allows the proxy records from MD99-2334K to be placed confidently on the GISP2 time-scale. This correlation is further corroborated by AMS C-14-dates. Benthic Mg/Ca measurements in MD99-2334K permit the reconstruction of past deep-water temperature (T-dw) changes since -34 cal. ka BP (calendar kiloyears before present). Using these...
Tipo: Text Palavras-chave: Deep-water temperature; Mg/Ca; Termination I; Thermohaline circulation; Paleoceanographycal and chemical : trace elements; Oceanography : biological and chemical : trace elements; Oceanography : biological and chemical : stable isotopes.
Ano: 2003 URL: https://archimer.ifremer.fr/doc/00225/33654/32087.pdf
Registros recuperados: 3
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