Dissolution theory, calcite

Berner, R.A. Morse, J.M. 1974. Dissolution kinetics of calcium carbonate in seawater. IV. Theory of calcite dissolution, American Journal of Science, 274,108-134. 

Thus, larger solid/water ratios such as are encountered in pore waters of sediments lead to smaller MgC(>3 contents in the equilibrium magnesian calcites although in either case the magnesium content of the solid increases. Wollast and Reinhard-Derie presented data to support the theory from the standpoint of dissolution and some of our results for the precipitation case... 

Many natural aquatic systems have a chemical composition close to saturation with respect to calcite or even dolomite. This is the case, for instance, for seawater, which is usually slightly oversaturated in the upper part of the water column and slightly undersaturated at greater depths. Under these conditions, the rates of both precipitation and dissolution contribute significantly to the overall rate of reaction. Even though the reaction paths may be very complex, there is a very direct and important link between the kinetic rate constants, according to which the rates of forward and reverse microscopic processes are equal for every elementary reaction. The fundamental aspect of this principle forms the essential aspect of the theory of irreversible thermodynamics (Frigogine, 1967). 

Several studies support the idea that the chemical composition of biogenic carbonate is modified by partial dissolution under the infiuence of bottom waters or porewaters that are undersaturated with respect to calcium carbonate (e.g. Rosenthal et al. 2000). In a study of planktonic foraminifera conducted by Brown Elderfield (1996), artificial partial dissolution of G. tumida tests resulted in a decrease in both Mg/Ca and Sr/Ca, but there was no significant change for G. sacculifer. The cause of this reduction is thought to be preferential dissolution of high-Mg inner (chamber) calcite, which forms in warmer waters than the low-Mg calcite crust (keel). In theory, it should be possible to correct for such effects if the extent of dissolution can be quantified. A number of dissolution indicators, including foraminiferal test weights (e.g. Broecker Clark 2001) and calcite crystallinity (Bassinot et al. 2004), have been tested, but none have been widely applied to date. 

---