• journal_title：Mineralogical Magazine
• Contributor：G. Balassone ; F. Bellatreccia ; A. Mormone ; C. Biagioni ; M. Pasero ; C. Petti ; N. Mondillo ; G. Fameli
• Publisher：Mineralogical Society of Great Britain and Ireland
• Date：2012-
• Format：text/html
• Language：en
• Identifier：10.1180/minmag.2012.076.1.191
• journal_abbrev：Mineralogical Magazine
• issn：0026-461X
• volume：76
• issue：1
• firstpage：191
• section：CNMNC Newsletter 12

Sodalites and sulfatic sodalites in holocrystalline K-feldspar-rich ejecta from the Somma–Vesuvius volcanic complex, Italy, have been characterized by combined chemical, structural and spectroscopic analyses. Sodalite has a relatively homogeneous chemical composition, with the ubiquitous presence of class="inline-formula" id="inline-formula-1">class="math mml" alt="Formula" src="191/embed/mml-math-1.gif" /> and H₂O/OH⁻. The sulfatic sodalites are isomorphous and have cage structures which can contain a wide variety of anions, molecular species and cations. Molecular CO₂ and H₂O/OH⁻ are present in sulfatic sodalites, instead of the class="inline-formula" id="inline-formula-2">class="math mml" alt="Formula" src="191/embed/mml-math-2.gif" /> anions that are present in sodalite sensu stricto. The cell dimensions of the all of the studied sodalite samples are very similar, the sulfatic sodalite cell dimensions are more variable. Structure refinement of a distinctly green sample confirms the P4İ3n space group. Metasomatic magma-derived fluids that are rich in H₂O, CO₂, Cl and S are believed to be responsible for the genesis of the relatively late-stage phases which form the ejecta containing the sodalite-group minerals.