Printed in Great Britain P I I: S0967--0645(97)00039--8 0967~)645/98 $19.00 + 0.00 Radiocarbon chronology of depositional regimes in the western Arctic Ocean
Abstract--The foraminiferal bundance and percentage of coarse ice-rafted etritus (IRD) define glacial, deglacial, and interglacial depositional regimes in AMS radiocarbon-dated box cores from the western Arctic Ocean. Sediment deposition rates are generally less than 0.5 cm/ka for glacial regimes, g...
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| Format: | Text |
| Language: | English |
| Published: |
1997
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.540.6725 http://sci.odu.edu/oceanography/directory/faculty/darby/publications/Darby_et_al_1997.pdf |
| Summary: | Abstract--The foraminiferal bundance and percentage of coarse ice-rafted etritus (IRD) define glacial, deglacial, and interglacial depositional regimes in AMS radiocarbon-dated box cores from the western Arctic Ocean. Sediment deposition rates are generally less than 0.5 cm/ka for glacial regimes, greater than this for deglacial regimes and greater than 1-2 cm/ka for interglacial regimes. These differences in deposition rates might account for the much lower average sedimentation rates for the last 780 ka of 1-3 mm/ka in cores from the central Arctic Ocean if glacial regimes dominated this interval. Foraminiferal bundances are less than 500/g during glacial maxima nd mostly higher than 2000/g during deglacial and interglacial regimes. Slightly higher coarse IRD percentages occur in deglacial intervals (> 5-10 % up to 30%) compared with interglacial intervals (mostly <5%), which characterize the last 10-12 ka in the western Arctic Ocean. Glacial regimes occurred from about 40 to 11 ka except for a brief interglacial or deglacial interval around 24-28 ka in the central Arctic Ocean. The coarsest deglacial events occurred prior to 45 ka. The Late Wisconsin deglaciation sediments (approximately 9-16 ka) are difficult to detect in the central Arctic Ocean sediments because they are only slightly coarser than the Holocene and, in some box cores, less coarse than the Holocene. A previously unrecognized coarse IRD event occurred near the core tops (0-3 cm) between 1500 and 3500 radiocarbon years ago in the western Arctic Ocean. Only sediment older than 40 ka is coarser than this recent IRD event, which might correspond to a Neoglaciation recognized in |
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