Variable Quaternary chemical weathering fluxes and imbalances in marine geochemical budgets

Ocean geochemistry: just back-dated For many elements and isotopes in the oceans, river water is thought to be the dominant source. However this input from the continents is not perfectly balanced by the loss of these elements and isotopes from the oceans, for example, by hydrothermal and sedimentary exchange with the oceanic crust. To resolve this issue, attention has traditionally focused on uncertainties in hydrothermal fluxes. After all, the riverine input flux is directly and comprehensively observable. Vance et al. offer an alternative explanation for the imbalance in oceanic geochemical budgets. Modern day estimates of river flux are broadly accurate, they say, but a pulse of rapid chemical weathering initiated at the last deglaciation has not yet decayed away and is still feeding the rivers with elements and isotopes. They find that consideration of the suggested temporal variability in riverine fluxes largely ameliorates long-standing problems with chemical and isotopic mass balances in the ocean.