Comment on the “Self-accelerating dolomite-for-calcite replacement model: Self-organized dynamics of burial dolomitization and associated mineralization”, v. 311, n. 7, p. 573–607, by Enrique Merino and Àngels Canals

Abstract

A model for self-accelerating burial dolomitization proposed by Merino and Canals (2011) invokes a process of dolomitization via a dolomite crystal-growth-driven, pressure solution dissolution of calcite, rather than by dolomite precipitation following calcite dissolution in an open fluid-rock system. Their postulated exponential increase in the saturation of dolomite in solution, and massive dolomite precipitation during dolomitization, is not in accord with experimental data. Calcite precipitation during postulated increases in Ca²⁺ in solution, occasioned by the hypothesized volume conservative pressure driven dolomitization of calcite, will preclude extensive dolomite precipitation. The generally destructive character of dolomitization and the presence of porosity in many “zebra fabric” saddle dolomites within hydrothermal burial dolomites indicate that dolomitization does proceed in a more open system solution and precipitation environment than that proposed by Merino and Canals (2011).