کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9522274 | 1634966 | 2005 | 14 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
231Pa and 230Th in surface sediments of the Arctic Ocean: Implications for 231Pa/230Th fractionation, boundary scavenging, and advective export
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
علوم زمین و سیاره ای (عمومی)
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چکیده انگلیسی
Activities of 231Pa and 230Th in surface sediments from the Arctic Ocean and Greenland-Norwegian Seas are used to examine the redistribution of these water-column produced tracers between the low productivity interior basins and high particle flux marginal areas. Sediment 231Paxs/230Thxs ratios throughout the Canadian and Eurasian Basins and the high particle flux Chukchi slope region are essentially invariant (average = 0.063 ± 0.014, N = 39) and significantly below the water column production ratio (0.093). 231Paxs/230Thxs ratios are also below the production ratio in the seasonally high productivity Greenland-Norwegian Sea basins (average = 0.082 ± 0.024, N = 13), though they are â¼Â 30% higher than the interior Arctic. The low sediment 231Paxs/230Thxs ratios are attributed to the net export of â¼Â 39% of dissolved 231Pa produced in intermediate/deep waters, as opposed to â¼Â 10% of 230Th, through Fram Strait. The negligible 230Th export, combined with the reported low 230Thxs inventory of basin sediments and high 230Thxs inventory in Chukchi slope sediments, points to significant boundary scavenging of 230Th in the Arctic. The invariant 231Paxs/230Thxs ratios further indicate that scavenging of 230Th is comparable to 231Pa (i.e., fractionation to a similar degree between the two nuclides) in both the interior basins and margins. Thus, while significant boundary scavenging of both 231Pa and 230Th occurs in the Arctic, there is a distinct lack of basin-margin fractionation and a sizable export of 231Pa. There is also likely to be export of other similarly particle-reactive radionuclides (e.g., 10Be, Pu isotopes) out of the Arctic.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 234, Issues 1â2, 30 May 2005, Pages 235-248
Journal: Earth and Planetary Science Letters - Volume 234, Issues 1â2, 30 May 2005, Pages 235-248
نویسندگان
S.B. Moran, C.-C. Shen, R.L. Edwards, H.N. Edmonds, J.C. Scholten, J.N. Smith, T.-L. Ku,