Comparative fluxes of HCO3- and Si from glaciated and non-glaciated terrain during the last deglaciation.

peer reviewedThere is current interest in the riverine fluxes of bicarbonate and Si at the last glacial maximum (LGM), since modelling suggests that these were higher than today (Gibbs and Kump, 1994; Froelich et al., 1992). If this is the case, removal of atmospheric CO2 by silicate weathering is also likely to have been greater at the LGM (Munhoven and Francois, 1996), so contributing to the lower atmospheric CO2 recorded by ice cores (Barnola et al., 1987). To date, the magnitude of glacial chemical erosion on bicarbonate and Si fluxes at the LGM is poorly quantified, and the locus of the inferred doubled terrestrial Si flux is unknown. This paper aims to provide first estimates of the relative fluxes of bicarbonate and Si fluxes from ice-free and glaciated terrain for five time steps between the LGM (21ka), by extending the modelling approach of Gibbs and Kump (1994) and incorporating new data on glacial solute fluxes (Tranter et al., submitted)