Magnesian calcites stabilities

Walter, L.M. Morse, J.W. (1984) Magnesian calcite stabilities a reevaluation. Geochim. Cosmochim. Acta, 48, 1059-1069. 

Bischoff, W. D., F. T. Mackenzie, and F. C. Bishop (1987), "Stabilities of Synthetic Magnesian Calcites in Aqueous Solution Comparison with Biogenic Materials," Geochim. Cosmochim. Acfa51, 1413-1423. 

Figure 3.14. Stabilities of calcite, and synthetic (closed squares) and biogenic (closed circles) magnesian calcites as a function of composition. Stabilities are expressed as -log IAPMg-Calcite- The curve is a hand-drawn "best" fit to the synthetic data. Also plotted are the results of precipitation experiments by Mucci and Morse (1984, open squares) and biogenic dissolution experiments by Walter and Morse (1984a, open circles). (After Bischoff et al., 1987.)...

Another example of the "tricks" that metastability can play is that of the 15 mole % magnesian calcite, whose stability field is shown in Figure 6.IB. This phase... 

There is an extensive literature that exists concerning carbonate diagenesis in the vadose and phreatic meteoric environmental settings (see e.g., Bathurst, 1975, 1980 James and Choquette, 1984 and Moore, 1989 for reviews). Much of this work has dealt with the stabilization of aragonite and magnesian calcite to calcite in the present meteoric diagenetic realm associated with Pleistocene limestones. As... 

In contrast, Lafon and Vacher (1975) estimated the half-life of aragonite in the vadose zone of Bermuda as about 230,000 years, and the half-life of high-magnesian calcite as only 60,000 years. Minor corrections need to be made to these estimates, because of new estimates of limestone ages for Bermuda, but the fact still remains that stabilization in the vadose freshwater zone is much slower than in the phreatic zone (Land, 1970 Steinen and Matthews, 1973 Steinen, 1974 Vacher et al 1989). 

Although cementation is a process that can occur throughout the life of a sedimentary carbonate body, the dominant processes and types of cements produced generally differ substantially between those formed in the shallow-meteoric and deep-burial environments. Mineralogic stabilization (i.e., dissolution of magnesian calcites and aragonite, see Chapter 7) commonly drives cement formation during the early shallow-burial period, whereas the previously discussed processes of pressure solution and neomorphism are more important in the deep-burial environment. The pore waters in which cementation takes place also tend to differ substantially between the two environments. In shallow subsurface environments, cementation usually takes place in dilute meteoric waters that are oxic to only... 

Bischoff W.D. (1985) Magnesian calcites Physical and chemical properties and stabilities in aqueous solution of synthetic and biogenic phases. Ph.D. dissertation, Northwestern Univ.. 

Bischoff W.D., Mackenzie F.T. and Bishop F.C. (1987) Stabilities of synthetic magnesian calcites in aqueous solution Comparison with biogenicmaterials. Geochim. Cosmochim. Acta 51, 1413-1423. 

Solid inclined continuous line separates stability fields of calcite and dolomite, the horizontal dashed line restricts from the bottom crystallization field of aragonite or magnesian calcite. Different natural water distribution fields are shown by shading. 

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