Pore fluids and the LGM ocean salinity—Reconsidered
Author(s)
Wunsch, Carl Isaac
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Pore fluid chlorinity/salinity data from deep-sea cores related to the salinity maximum of the last glacial maximum (LGM) are analyzed using estimation methods deriving from linear control theory. With conventional diffusion coefficient values and no vertical advection, results show a very strong dependence upon initial conditions at −100 ky. Earlier inferences that the abyssal Southern Ocean was strongly salt-stratified in the LGM with a relatively fresh North Atlantic Ocean are found to be consistent within uncertainties of the salinity determination, which remain of order ±1 g/kg. However, an LGM Southern Ocean abyss with an important relative excess of salt is an assumption, one not required by existing core data. None of the present results show statistically significant abyssal salinity values above the global average, and results remain consistent, apart from a general increase owing to diminished sea level, with a more conventional salinity distribution having deep values lower than the global mean. The Southern Ocean core does show a higher salinity than the North Atlantic one on the Bermuda Rise at different water depths. Although much more sophisticated models of the pore-fluid salinity can be used, they will only increase the resulting uncertainties, unless considerably more data can be obtained. Results are consistent with complex regional variations in abyssal salinity during deglaciation, but none are statistically significant. Keywords: Last glacial maximum; Ocean salinity; Pore waters; Abyssal ocean
Date issued
2016-02Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary SciencesJournal
Quaternary Science Reviews
Publisher
Elsevier
Citation
Wunsch, Carl. "Pore fluids and the LGM ocean salinity—Reconsidered." Quaternary Science Reviews 135 (March 2016): 154-170 © 2016 Elsevier Ltd
Version: Author's final manuscript
ISSN
0277-3791