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Summary: Reconstructing Last Glacial Maximum bottom water salinities
from deep-sea sediment pore £uid pro¢les
Jess F. Adkins a;Ă
, Daniel P. Schrag b
a
MS 100-23, Division of Geology and Planetary Sciences, Caltech, Pasadena, CA 91125, USA
b
Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02139, USA
Received 31 March 2003; received in revised form 28 August 2003; accepted 5 September 2003
Abstract
Deep-sea sediment pore fluids contain a record of past glaciations in their [Cl] and N18
O. The signal of the Last
Glacial Maximum (LGM) ice volume increase remains in the pore fluids as a local peak in each of these species. Using
a one-dimensional model to account for the diffusive and advective transport within the sediment column since the
LGM, the past bottom water salinity and N18
Oseawater values can be estimated. The model is most sensitive to the
shape of the forcing function used to represent bottom water variations through time, the effective diffusion
coefficient, and the scatter in the data. Assuming steady-state compaction, the model is relatively insensitive to the
initial condition, the bulk sedimentation rate and the assumed porosity profile, though these last two are measured
independently. Overall uncertainties in the relative [Cl] increase at the LGM are between 0.1 and 0.5%, where the
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