Carbonate grains dissolution

Walter, L. M., and J. W. Morse (1984b), "Reactive Surface Area of Skeletal Carbonates During Dissolution Effect of Grain Size", J. Sediment. Petrol 54,1081-1090. 

Walter L.M. (1983) The dissolution kinetics of shallow water carbonate grain types Effects of mineralogy, microstructure and dolution chemistry. Ph.D. dissertation, Univ. Miami, Miami, FL. 

Walter L.M. and Morse J.W. (1984b) Reactive surface area of skeletal carbonates during dissolution Effect of grain size. J. Sediment. Petrol. 54, 1081-1090. 

Dissolution of carbonate grains may occur as a consequence of (i) a build up of Pqo, the vadose zone due to the extensive respiration of plants and micro-organisms (ii) an increase in the concentration of organic (humic-fulvic) acids due to secretion by, or decay of, plants and (iii) mixing between waters with chemically dilferent compositions, particularly in terms of Pco, (c-g- vadose and phreatic waters), which is referred to as mixing corrosion (Wigley Plummer, 1976). 

The amounts of calcite cement in the host rocks show a positive correlation with the amount of carbonate grains (Fig. 6). This indicates calcite cement precipitation after dissolution of metastable carbonate grains. Stable carbonate grains (which survived dissolution) served as nuclei for late calcite cement in host rocks. Within lenses, late calcite cement merely filled all available pores, which can be ascribed to either an abundance of nuclei or locally low permeability. The lack of correlation between calcite cement and secondary porosity suggests relatively long-range transport of dissolved CaCOj. Late calcite cement precipitated preferentially within lenses that contained more calcite nuclei than surrounding host rocks. 

The magnitude of porosity enhancement due to aluminosilicate grain dissolution in a reservoir and source-rock system depends on facies relationships, variations in original composition, formation of subsequent cements, availability of fluid conduits, fluid flux, and the proximity of organic-rich source rocks in hydrologic connection with the reservoir rock. In contrast, carbonate decementation and mass transfer apparently can occur on a scale larger than a specific reservoir and source-rock system (Schultz et al. 1989). 

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