Pore Fluids and the LGM Ocean Salinity–Reconsidered

4 Pore fluid chlorinity/salinity data from deep-sea cores related to the salinity maximum 5 of the last glacial maximum (LGM) are analyzed using estimation methods deriving from 6 linear control theory. With conventional diffusion coefficient values and no vertical advection, 7 results show a very strong dependence upon initial conditions at -100 ky. Earlier inferences 8 that the abyssal Southern Ocean was strongly salt-stratified in the LGM with a relatively 9 fresh North Atlantic Ocean are found to be consistent within uncertainties of the salinity 10 determination, which remain of order ±1 g/kg. However, an LGM Southern Ocean abyss 11 with an important relative excess of salt is an assumption, one not required by existing 12 core data. None of the present results show statistically significant abyssal salinity values 13 above the global average, and results remain consistent, apart from a general increase owing 14 to diminished sea level, with a more conventional salinity distribution having deep values 15 lower than the global mean. The Southern Ocean core does show a higher salinity than 16 the North Atlantic one on the Bermuda Rise at different water depths. Although much 17 more sophisticated models of the pore-fluid salinity can be used, they will only increase 18 the resulting uncertainties, unless considerably more data can be obtained. Results are 19 consistent with complex regional variations in abyssal salinity during deglaciation, but none 20 are statistically significant. 21