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Comment on ''Do geochemical estimates of sediment focusing pass the sediment test in the equatorial Pacific?'' by M. Lyle et al


Francois, R and Frank, M and Rutgers van der Loeff, M and Bacon, MP and Geibert, W and Kienast, S and Anderson, RF and Bradtmiller, L and Chase, Z and Henderson, G and Marcantonio, F and Allen, SE, Comment on ''Do geochemical estimates of sediment focusing pass the sediment test in the equatorial Pacific?'' by M. Lyle et al, Paleoceanography, 22 pp. PA1216. ISSN 0883-8305 (2007) [Refereed Article]

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Copyright 2007 American Geophysical Union

DOI: doi:10.1029/2005PA001235


Accurately estimating the vertical flux of material reaching the seafloor from the overlying surface waters is essential for the paleoceanographic reconstruction of a wide variety of oceanic processes. Two approaches are currently being used. One consists of estimating mass accumulation rates (MAR) between dated horizons as the product of linear sedimentation rates, sediment dry bulk densities, and concentrations. One pitfall with this approach is that sediments can be redistributed on the seafloor by bottom currents, and their accumulation may not necessarily reflect the true vertical rain rate originating from the overlying water column. To address this problem, the method of 230Th normalization was developed [Bacon, 1984]. This method is based on the assumption that the rapid scavenging of 230Th produced in the water column by decay of dissolved uranium results in its flux to the seafloor always being close to its known rate of production. To the extent that this assumption is correct, scavenged 230Th can be used as a reference to estimate the settling flux of other sedimentary constituents and to correct for sediment redistribution on the seafloor [Henderson and Anderson, 2003; Francois et al., 2004].

Item Details

Item Type:Refereed Article
Keywords:230Th particle flux
Research Division:Earth Sciences
Research Group:Physical geography and environmental geoscience
Research Field:Palaeoclimatology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the earth sciences
UTAS Author:Chase, Z (Professor Zanna Chase)
ID Code:79533
Year Published:2007
Web of Science® Times Cited:39
Deposited By:IMAS Research and Education Centre
Deposited On:2012-09-18
Last Modified:2012-11-06

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