Cement calcite

Reeder R.J., Grans J.C. Sector zoning on calcite cement crystals Implications for trace element fistrubtions in carbonates. Geochim Cosmochim Acta 1987 51 187-194. 

The rock in question might contain a large amount of calcite cement, but the reaction path predicts that only a trace of calcite forms during burial. Considering this contradiction, the modeler realizes that this model could not have been successful in the first place there is not enough calcium or carbonate in seawater to have formed that amount of cement. The model in this case was improperly conceptualized as a closed rather than open system. 

Meyers, W. J. and K. C. Lohmann, 1985, Isotope geochemistry of regional extensive calcite cement zones and marine components in Mississippian limestones, New Mexico. In N. Schneidermann and P. M. Harris (eds.), Carbonate Cements. SEPM Special Publication 36,223-239. 

Hays PD, Grossman EL (1991) Oxygen isotopes in meteoric calcite cements as indicators of continental paleoclimate. Geology 19 441 44... 

A.A. Mirtchi, J. Lemaitre, E. Munting, Calcium phosphate cements Effect of fluorides on the setting and hardening of beta-tricalcium phosphate-dicalcium phosphate-calcite cements. Biomaterials 12 (1991) 505-510. 

R. J. Reeder and J. C. Grams, Sector zoning in calcite cement Implications for trace element distributions in carbonates, Geochim. Cosmochim. Acta, 51,1987,187-94... 

Figure 4.25. Distribution of Mg contents of magnesian calcite cements in marine sediments. (After Mucci, 1987.)...

It can be demonstrated that grain boundaries or microcracks in sediments are preferred environments of cement nucleation. Consider the environment between two grains of carbonate separated by a void area of radius r (Figure 7.17 ) the energy (AFcav) required for the formation of calcite cement domains in such a cavity of height h and radius r is ... 

Wetzel (1989) calculated the volume of calcite cement at the two DSDP sites. The results of these calculations are shown in Figure 8.19. It can be seen that the calculated rate of increase of cement volume with increasing depth at the high heat flow area of site 504 is greater than that of the low heat flow site 505. 

It is unlikely, however, that the lithification of chalk will go on without consolidation, in which the volume of chalk material is reduced in response to a load on the chalk. Consolidation can lead to a reduction in porosity up to about 40%, and an increase in the effective stress (Jones et al., 1984). The increased effective stress is required to instigate the process of pressure solution. Pressure solution provides Ca2+ and HCO3 for early precipitation of calcite cement in the chalk. However, the inherently low permeability of chalk would inhibit the processes of consolidation and pressure solution/cementation unless some permeable pathways are opened up to permit the dissipation of excess pore pressure created by the filling of pore space by calcite cement. Pressure solution will cease if the permeable pathways are blocked by cement. Thus, it appears that the development of fractures, open stylolites and microstylolitic seams (Ekdale et al., 1988) is necessary to permit pressure solution to continue and lead to large rates of Ca2+ and HC03 mobilization. 

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