Comment on ''Do geochemical estimates of sediment focusing pass the sediment test in the equatorial Pacific?'' by M. Lyle et al
2007
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].
Keywords:
- Correction
- Source
- Cite
- Save
- Machine Reading By IdeaReader
30
References
49
Citations
NaN
KQI