Magnesium in continental runoff

A mass balance for Mg in continental runoff has been constructed. The sources of runoff Mg in this model are cyclic salts, carbonate rock and silicate rock weathering. The calculations indicate that the Mg concentration reported for average continental runoff is anomalously high. The anomaly may be due to recent disturbances in the weathering regimes of calcite, dolomite and silicates, or to unreliable Mg concentrations reported in older analyses.