Calcite crystal growth

Folk R.L. (1978) A chemical model for calcite crystal growth and morphology control. J. Sediment. Petrol. 48, 345-347. 

It is apparent from our calculations of the rate of calcite crystal growth that the agreement in computed and observed rate is far more satisfactory at higher PCO2 than low PCO2 ... 

Reddy, M.M., and Nancollas, G.H. Calcite crystal growth inhibition by phosphonates. Desalination 12, 61-73 (1973). Reddy, M.M., Kinetics of calcium carbonate formation. Proc. Internat. Assoc. Theoret. Appl. 

Figure 6. Thin section photographs of fluid inclusions in culcite. Primary fluid inclusions (dark) occur along well-defined calcite crystal growth zones. Scale bars are 100/zm. (From Goldstein Reynolds. 1994, Fig. 2.5, p. 10).

Spanos, N. and Koutsoukos, P.G., 1998. The transformation of vaterite to calcite effect of the conditions of the solutions in contact with the mineral phase. Journal of Crystal Growth, 191, 783-790. 

Uranium is distributed uniformly within individual growth layers, but varies greatly in concentration between successive layers (A, B, and C). The distribution of tracks suggests that U is distributed homogeneously in single calcite crystals, and is not concentrated at grain boundaries or in inclusions. 

Busenberg, E. Plummer, L.N. 1986. A comparative study of the dissolution and crystal growth kinetics of calcite and aragonite. U S. Geological Survey Bulletin, 1578, 139-168. 

The crystal growth of calcite has been studied by Plummer and coworkers (1978), by Kunz and Stumm (1984) and by Chou and Wollast (1989) to correspond to the backward rate of dissolution (Eq. 8.3). 

Busenberg, E., and L. N. Plummer (1986b), "A Comparative Study of the Dissolution and Crystal Growth Kinetics of Calcite and Aragonite", in F. A. Mumpton, Ed., Studies in Diagenesis, U.S. Geol. Surv. Bull. 1578, pp. 139-168. 

Calcium phosphate precipitation may also be involved in the fixation of phosphate fertilizer in soils. Studies of the uptake of phosphate on calcium carbonate surfaces at low phosphate concentrations typical of those in soils, reveal that the threshold concentration for the precipitation of the calcium phosphate phases from solution is considerably increased in the pH range 8.5 -9.0 (3). It was concluded that the presence of carbonate ion from the calcite inhibits the nucleation of calcium phosphate phases under these conditions. A recent study of the seeded crystal growth of calcite from metastable supersaturated solutions of calcium carbonate, has shown that the presence of orthophosphate ion at a concentration as low as 10-6 mol L" and a pH of 8.5 has a remarkable inhibiting influence on the rate of crystallization (4). A seeded growth study of the influence of carbonate on hydroxyapatite crystallization has also shown an appreciable inhibiting influence of carbonate ion.(5). 

Figure 17. Plot of Li isotopic composition vs. temperature of growth for synthetic calcite crystallized from a solution containing Li from L-SVEC (Marriott et al. 2004). The results are most consistent with temperature not being a significant control on mass fractionation of Li during crystallization from aqueous solution, thus essentially eliminating Li isotopes as a paleotemperature proxy in marine carbonates.

Figure 7.10. (a) Sketches and (b) photograph of parallel growth due to preferential nucleation at the corners and along the edges of existing calcite crystals (ref. [3], Chapter 11). Note the Habitus change between earlier and later formed crystals. 

Figure 11.5(b) shows that the later-formed calcite crystal has a different Habitus from the earlier-formed prismatic crystal around which it grows, and Fig. 11.5(c) is an example of the growth of a crystal with dog-tooth Habitus on an earlier-formed crystal with rhombohedral Habitus. (See also Fig. 7.10.) By compiling these relations, it is possible to trace systematically how the Habitus of calcite changes from earlier to later stages or as the temperature decreases in the case of contact metasomatism [2], [3]. The Habitus variation with decreasing temperature summarized above is a general trend based on data of this type.

Figure 11.5. Three examples showing different Habitus of later-grown calcite crystals preferentially nucleated on the edges and corners of earlier-formed calcite crystal. Changes in Habitus depending on crystallization stages or growth temperatures are indicated [3]. (a) Earlier-formed hexagonal prism (A) and later-formed scalenohedral crystal (B). (b) Earlier-formed hexagonal prism (b) and later-formed thicker crystal (a), (c) The shaded area shows an earlier-formed rhombohedral crystal, and the remaining area represents later-formed scalenohedral crystals.

There is no doubt that the Habitus of calcite crystals forming the exo-skeleton of coccoliths is designed naturally to match the function of spicules, but further investigation may be required to explain the growth mechanism of this peculiar form and the relations between R and V crystals. 

Berner, R. A. The role of magnesium in the crystal growth of calcite and aragonite from seawater. Geochim. Cosmochim. Acta 39. 489-504 (1975). 

One of the most controversial topics in the recent literature, with regard to partition coefficients in carbonates, has been the effect of precipitation rates on values of the partition coefficients. The fact that partition coefficients can be substantially influenced by crystal growth rates has been well established for years in the chemical literature, and interesting models have been produced to explain experimental observations (e.g., for a simple summary see Ohara and Reid, 1973). The two basic modes of control postulated involve mass transport properties and surface reaction kinetics. Without getting into detailed theory, it is perhaps sufficient to point out that kinetic influences can cause both increases and decreases in partition coefficients. At high rates of precipitation, there is even a chance for the physical process of occlusion of adsorbates to occur. In summary, there is no reason to expect that partition coefficients in calcite should not be precipitation rate dependent. Two major questions are (1) how sensitive to reaction rate are the partition coefficients of interest and (2) will this variation of partition coefficients with rate be of significance to important natural processes Unless the first question is acceptably answered, it will obviously be difficult to deal with the second question. 

---