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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, Roger; Allen, Susan E.
Abstract
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]. An edited version of this paper was published by AGU. Copyright 2007 American Geophysical Union.
Item Metadata
Title |
Comment on “Do geochemical estimates of sediment focusing pass the sediment test in the equatorial Pacific?” by M. Lyle et al.
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Creator | |
Contributor | |
Publisher |
American Geophysical Union
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Date Issued |
2007-03-06
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Description |
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].
An edited version of this paper was published by AGU. Copyright 2007 American Geophysical Union.
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Subject | |
Genre | |
Type | |
Language |
eng
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Date Available |
2017-01-11
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Provider |
Vancouver : University of British Columbia Library
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Rights |
Attribution-NonCommercial-NoDerivatives 4.0 International
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DOI |
10.14288/1.0078395
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URI | |
Affiliation | |
Citation |
Francois, Roger; Frank, Martin; van der Loeff, Michiel Rutgers; Bacon, Michael P.; Geibert, Walter; Kienast, Stephanie S.; Anderson, Robert F.; Bradtmiller, Louisa; Chase, Zanna; Henderson, Gideon; Marcantonio, Franco; Allen, Susan E.. 2007. Comment on “Do geochemical estimates of sediment focusing pass the sediment test in the equatorial Pacific?” by M. Lyle et al., Paleoceanography, 22, PA1216.
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Publisher DOI |
10.1029/2005PA001235
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Peer Review Status |
Reviewed
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Scholarly Level |
Faculty
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Copyright Holder |
Francois, Roger
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Rights URI | |
Aggregated Source Repository |
DSpace
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Item Citations and Data
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International