Zusammenfassung
A 10.5 m core from Changeable Lake in the Severnaya Zemlya Archipelago just north of the Taymyr Peninsula intersects ca. 30 cm of diamicton at its base, interpreted as a basal till. Because the upper 10.13 m of this core consists of non-glacial sediments, a maximum numeric age for these non-glacial sediments would provide a clear lower limit to the timing of the last glaciation in the area of ...
Zusammenfassung
A 10.5 m core from Changeable Lake in the Severnaya Zemlya Archipelago just north of the Taymyr Peninsula intersects ca. 30 cm of diamicton at its base, interpreted as a basal till. Because the upper 10.13 m of this core consists of non-glacial sediments, a maximum numeric age for these non-glacial sediments would provide a clear lower limit to the timing of the last glaciation in the area of Changeable Lake. Radiocarbon (C-14) dating of several materials from this core yielded widely scattered results. Consequently we applied photonic dating to sediments above the diamicton. The experimental single-aliquot-regenerative (SAR) dose fine-grain method was applied to two samples, using the 'double SAR' approach. With one exception, these fine-grain SAR results and the results of application of the SAR method to sand-sized quartz grains from two samples, at ca. 9.95 m and ca. 10.05 m depth, are discrepant with age estimates from the multi-aliquot infrared-photon-stimulated luminescence (IR-PSL) method applied to fine grains. Multi-aliquot IR-PSL dating of 10 samples produces ages increasing monotonically from ca. 4 ka at 2 m to 53 +/- 4 ka at 9.97 m. These self-consistent multi-aliquot IR-PSL ages, along with limiting C-14 ages of >47 ka at ca. 10 m, provide direct evidence that glacial ice did not advance over this lake basin during the Last Glacial Maximum, and thus delimit the northeastern margin of the Barents-Kara Sea ice-sheet to somewhere west of this archipelago. The last regional glaciation probably occurred during marine isotope stage (MIS) 4 or earlier. Copyright (C) 2004 John Wiley Sons, Ltd.
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