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要旨:
We present Delta 14C data collected during three cruises to the Arctic Ocean that took place in the summers of 1987 (POLARSTERN cruise ARK IV/3), 1991 (ARCTIC 91 Expedition), and 1994 (Arctic Ocean Section 94). The cruise tracks of these three expeditions cover all major basins of the Arctic Ocean (Nansen, Amundsen, Makarov and Canada basins), and can be combined to a trans.Arctic section reaching from the Barents Sea slope to the southern Canada Basin just north of Bering Strait. The section is based on I7 stations covering the entire water column (about 250 data points). The combined Delta 14C data set was produced from a mixture of large volume samples measured by low-level counting and small volume samples measured by Accelerator Mass Spectrometry (AMS). We use the Delta 14 C section, together with previously published
Delta 14C data from single stations located in several basins of the Arctic Ocean, to derive mean “ages” (isolation times) of the
deep waters in the Arctic Ocean. We estimate these mean “ages” to be = 250 years in the bottom waters of the Eurasian
Basin and = 450 years in the Canadian Basin Deep Water. A remarkable feature of the A”C section is the homogeneity in
the “?I distribution observed in the deep Canadian Basin. Within the measurement precision of about + 2% (LV) to about
f 5% (AMS). we cannot detect significant horizontal or vertical A14C gradients below 2000 m depth between the northern
boundary of the Makarov Basin and the southern margin of the Canada Basin. There is no statistically significant difference
between samples measured by AMS and by low-level counting.
