P. Schlosser et al., ON THE C-14 AND AR-39 DISTRIBUTION IN THE CENTRAL ARCTIC-OCEAN - IMPLICATIONS FOR DEEP-WATER FORMATION, Radiocarbon, 36(3), 1994, pp. 327-343
We present Delta(14)C, and Ar-39 data collected in the Nansen, Amundse
n and Makarov basins during two expeditions to the central Arctic Ocea
n (RV Polarstern cruises ARK IV/3, 1987 and ARK VIII/3, 1991). The dat
a are used, together with published Delta(14)C values, to describe the
distribution of Delta(14)C in all major basins of the Arctic Ocean (N
ansen, Amundsen, Makarov and Canada Basins), as well as the Ar-39 dist
ribution in the Nansen Basin and the deep waters of the Amundsen and M
akarov Basins. From the combined Delta(14)C and Ar-39 distributions, w
e derive information on the mean ''isolation ages'' of the deep and bo
ttom waters of the Arctic Ocean. The data point toward mean ages of th
e bottom waters in the Eurasian Basin (Nansen and Amundsen Basins) of
ca. 250-300 yr. The deep waters of the Amundsen Basin show slightly hi
gher H-3 concentrations than those in the Nansen Basin, indicating the
addition of a higher fraction of water that has been at the sea surfa
ce during the past few decades. Correction for the bomb C-14 added to
the deep waters along with bomb H-3 yields isolation ages for the bulk
of the deep and bottom waters of the Amundsen Basin similar to those
estimated for the Nansen Basin. This finding agrees well with the Ar-3
9 data. Deep and bottom waters in the Canadian Basin (Makarov and Cana
da Basins) are very homogeneous, with an isolation age of ca. 450 yr.
Delta(14)C and Ar-39 data and a simple inverse model treating the Cana
dian Basin Deep Water (CBDW) as one well-mixed reservoir renewed by a
mixture of Atlantic Water (29%), Eurasian Basin Deep Water (69%) and b
rine-enriched shelf water (2%) yield a mean residence time of CBDW of
ca. 300 yr.