Preservation of particulate non-lithogenic uranium in marine sediments

Publication Type  Journal Article
Year of Publication  2002
Authors  Zheng, Y.; Anderson, R. F.; Van Geen, A.; Fleisher, M. Q.
Journal Title  Geochimica Et Cosmochimica Acta
Volume  66
Issue  17
Pages  3085-3092
Journal Date  Sep
ISBN Number  0016-7037
Accession Number  ISI:000177960600007
Key Words  santa-barbara basin; southern-ocean; water; enrichments; deposition; seawater

Particulate non-lithogenic uranium (PNU), excess U above detrital background levels found in marine particulate matter, is formed in surface waters throughout the ocean. Previous studies have shown that PNU is regenerated completely prior to burial of particles in sediments within well-oxygenated open-ocean regions. However, the fate of PNU has never been examined in ocean margin regions or in anoxic basins. Here we evaluate the preservation of PNU in ocean margin sediments and within semi-enclosed basins using samples from sediment traps deployed at multiple depths and surface sediments. Organic carbon fluxes at the sediment trap locations ranged from 0.1 to 4.3 g/cm(2) kyr, while the dissolved oxygen concentration in the water column ranged from <3 muM to similar to 270 muM. Preservation of PNU increases with decreasing dissolved oxygen concentration, approaching 100% preservation at oxygen concentration < 25 muM. PNU contributes as much as 40 to 70% of the total authigenic U in sediments in the Santa Barbara Basin and seasonally anoxic Saanich Inlet, and some 10% to 50% of the total authigenic U in sediments off the central California Margin. Copyright (C) 2002 Elsevier Science Ltd.


592WVTimes Cited:20Cited References Count:28

URL  <Go to ISI>://000177960600007
DOI  Pii S0016-7037(01)00632-9