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Metasomatic Replacement of Albite in Nature and Experiments

Drüppel, Kirsten; Wirth, Richard

Replacement of albite by sodium-rich, secondary phases is a common phenomenon, observed in different geological settings and commonly attributed to alkaline metasomatism. We investigated growth of nepheline and sodalite on albite in time series experiments between two and 14 days. A total of 42 hydrothermal experiments were performed in cold-seal hydrothermal vessels at a constant pressure of 4 kbar and 200–800 °C in the system SiO2–Al2O3–NaCl–H2O. To allow for fluid flow and material transport, a double-capsule technique was used; hereby, a perforated inner Pt capsule was filled with cleavage fragments of natural albite, whereas the shut outer Au capsule was filled with γ-Al2O3 and the NaCl–H2O solution. Complete overgrowth of albite by sodalite and nepheline occurred after just two days of experiments. At high salinity (≥17 wt % NaCl) sodalite is the stable reaction product over the whole temperature range whereas nepheline occurs at a lower relative bulk salinity than sodalite and is restricted to a high temperature of ≥700 °C. The transformation of albite starts along its grain margins, cracks or twin lamellae. Along the reaction front sodalite crystallizes as small euhedral and highly porous grains forming polycrystalline aggregates. ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000082980
Veröffentlicht am 22.05.2018
DOI: 10.3390/min8050214
Zitationen: 2
Web of Science
Zitationen: 2
Zugehörige Institution(en) am KIT Institut für Angewandte Geowissenschaften (AGW)
Publikationstyp Zeitschriftenaufsatz
Jahr 2018
Sprache Englisch
Identifikator ISSN: 2075-163X
KITopen-ID: 1000082980
Erschienen in Minerals
Band 8
Heft 5
Seiten Article: 214
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
Vorab online veröffentlicht am 17.05.2018
Schlagworte albite; amorphous; analcime; dissolution–precipitation; hydrothermal experiments; metasomatism; nepheline; sodalite
Nachgewiesen in Web of Science
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