Quick
Search: 		  
advanced search
 GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help 
Mineralogical Magazine Don't get GSW? Talk to your librarian.
JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Published online 4 August 2009
Mineralogical Magazine; April 2009; v. 73; no. 2; p. 269-284; DOI: 10.1180/minmag.2009.073.2.269
© 2009 Mineralogical Society of Great Britain and Ireland
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Google Scholar
Right arrow Articles by Katsikopoulos, D.
Right arrow Articles by Prieto, M.

Crystallization behaviour of the (Mn,Ca)CO3 solid solution in silica gel: nucleation, growth and zoning phenomena

D. Katsikopoulos*, Á. Fernández-González and M. Prieto

Departamento de Geología, Universidad de Oviedo, C/Jesús Arias de Velasco, s/n, 33005 Oviedo, Spain

* E-mail: dionisis{at}geol.uniovi.es

The nucleation and growth behaviour of the (Mn,Ca)CO3 solid solution from aqueous solutions in silica hydrogel were studied at 25°C. In order to obtain different levels of supersaturation at nucleation, experiments were carried out in diffusion columns of different lengths. Zoning phenomena, compositional heterogeneity and morphological modifications of the crystals obtained were examined by electron microprobe and scanning electron microscopy and microanalyses. The large difference between the solubility of calcite (CaCO3) and rhodochrosite (MnCO3) implies a significant preferential partitioning of Mn towards the solid. The distribution of Mn2+ and Ca2+ ions between the aqueous and solid phase demonstrates that at elevated supersaturation, this preferential partitioning is softened. The morphologies of experimentally grown individuals show a clear dependence on the composition of the parent solution. Crystals obtained from aqueous solutions with large Mn contents exhibit a relatively sharp concentric zoning along the equatorial sections. On these bases, the roles of multiple kinetic and thermodynamic factors during nucleation and growth are also discussed. Finally, an X-ray diffraction analysis of the precipitates provided no evidence of the formation of the dolomite-type ordered kutnahorite [CaMn(CO3)2] in any of the experimental sets.

KEYWORDS: calcite, rhodochrosite, solid solution, supersaturation, concentric zoning






JOURNAL HOME HELP CONTACT PUBLISHER SUBSCRIBE ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2009 by Mineralogical Society of Great Britain and Ireland