Cd2+ en calcita: Cristalización de la solución sólida (Cd, Ca)CO3.

  1. A. Fernández-González 1
  2. M. Prieto 1
  3. S. López-Andrés 2
  4. A. Putnis 3
  1. 1 Departamento de Geología, Universidad de Oviedo, 33005 Oviedo, España.
  2. 2 Departamento de Cristalografía y Mineralogía, Universidad Complutense, 28040 Madrid, España.
  3. 3 lnstitut für Mineralogie, Universitat Munster, D-48149 Münster, Alemania.
Revista:
Geogaceta

ISSN: 0213-683X

Any de publicació: 1996

Número: 20

Pàgines: 1546-1549

Tipus: Article

Altres publicacions en: Geogaceta

Resum

The complete series of the otavite-calcite solid has been synthesized by counter diffusion of CdCl2 +CaCl2 and CaCO3 through a column of silica hydrogel. In this system there is a strong preferential partitioning of Cd in the solid phase, and only a very narrow range of aqueous phase compositions can coexist in equilibrium with intermediate solid solutions, i.e., the (Cd, Ca)CO3 solid solution tend to crystallize from aqueous solutions in a bimodal way. At high supersaturations, the range of aqueous solutions from which intermediate solid solutions can nucleate expands, but the bimodal effect remains. This bimodal behaviour accounts for the development of high gradient composistional zoning and oscillatory zoning during the growth process.