Pore fluid constraints on deep ocean temperature and salinity during the Last Glacial Maximum

Abstract

Pore water records of δ^(18)O and [Cl] from ODP Site 1063A on the Bermuda Rise constrain the change in seawater δ^(18)O and salinity from the Last Glacial Maximum (LGM) to the Holocene to be 0.75±0.05‰ and 2.5±0.1% respectively. Coupled with a measured benthic foraminiferal δ^(18)O change, this result means that bottom waters were 4.6±0.8°C cooler than the Holocene at the LGM and therefore at or near the seawater freezing point. Coupled δ^(18)O and chlorinity results give an extrapolated mean ocean LGM to Holocene change in δ^(18)O of 0.95±0.09‰. These data also constrain the past southern source deep‐water salinity to be 35.76±0.04 psu, which is within error of the mean deep ocean value for this time.

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