Minerals weathering reactions

In the previous section the present-day cycle of carbon was discussed in some detail. We can now turn our attention to the sources of carbon to the ocean, and of calcium and magnesium, the major elements (other than oxygen and hydrogen) with which carbon interacts. Because carbon dioxide is the major acid gas involved in both carbonate and silicate mineral weathering reactions at the Earth s surface, it is informative to consider the sources of other elements as well. 

Therefore, as an oxide mineral weathers, reactions of C02 and water at the surface lead to the formation of carbonates and bicarbonates. The presence of OH can eventually cause... 

Katz B. G. (1989) Influence of mineral weathering reactions on the chemical composition of soil water, springs, and groundwater, Catoctin mountains, Maryland. Hydrol. Process. 3, 185-202. 

Clow D. W., Mast M. A., Bullen T. D., and Turk J. T. (1997) Strontium 87/strontium 86 as a tracer of mineral weathering reactions and calcium sources in an alpine/subalpine watershed. Loch Vale, Colorado. Water Resour. Res. 33, 1335-1351. 

Silicate and aluminosilicate mineral-weathering reactions involve both H -ion attack on the mineral and hydration or hydrolysis of the product minerals (clays and metal oxyhydroxides) or product aqueous species. If the primary mineral contains aluminum, then clays may result from the weathering. If the primary mineral contains Fe(II) or other reduced metal ions, weathering may involve oxidation as well as hydrolysis. 

Steinmann, P., P. C. Lichtner, and W. Shotyk. 1994. Reaction path approach to mineral weathering reactions. Clays Clay Minerals 42(2) 197-206. 

---