Zitieren Sie bitte immer diesen URN: urn:nbn:de:kobv:b43-554496
Lithium and boron difusivity and isotopic fractionation in hydrated rhyolitic melts
- Lithium and boron are trace components of magmas, released during exsolution of a gas phase during volcanic activity. In this study, we determine the difusivity and isotopic fractionation of Li and B in hydrous silicate melts. Two glasses were synthesized with the same rhyolitic composition (4.2 wt% water), having diferent Li and B contents; these were studied in difusion-couple experiments that were performed using an internally heated pressure vessel, operated at 300 MPa in the temperature range 700–1250 °C for durations from 0 s to 24 h. From this we determined activation energies for Li and B difusion of 57±4 kJ/mol and 152±15 kJ/mol with pre-exponential factors of 1.53 × 10–7 m2/s and 3.80× 10–8 m2 /s, respectively. Lithium isotopic fractionation during difusion gave β values between 0.15 and 0.20, whereas B showed no clear isotopic fractionation. Our Li difusivities and isotopic fractionation results difer somewhat from earlier published values, but overall confrm that LiLithium and boron are trace components of magmas, released during exsolution of a gas phase during volcanic activity. In this study, we determine the difusivity and isotopic fractionation of Li and B in hydrous silicate melts. Two glasses were synthesized with the same rhyolitic composition (4.2 wt% water), having diferent Li and B contents; these were studied in difusion-couple experiments that were performed using an internally heated pressure vessel, operated at 300 MPa in the temperature range 700–1250 °C for durations from 0 s to 24 h. From this we determined activation energies for Li and B difusion of 57±4 kJ/mol and 152±15 kJ/mol with pre-exponential factors of 1.53 × 10–7 m2/s and 3.80× 10–8 m2 /s, respectively. Lithium isotopic fractionation during difusion gave β values between 0.15 and 0.20, whereas B showed no clear isotopic fractionation. Our Li difusivities and isotopic fractionation results difer somewhat from earlier published values, but overall confrm that Li difusivity increases with water content. Our results on B difusion show that similarly to Li, B mobility increases in the presence of water. By applying the Eyring relation, we confrm that B difusivity is limited by viscous fow in silicate melts. Our results on Li and B difusion present a new tool for understanding degassing-related processes, ofering a potential geospeedometer to measure volcanic ascent rates.…
Autor*innen: | Roberta Spallanzani, K. Koga, S. Cichy, M. Wiedenbeck, B. Schmidt, Marcus OelzeORCiD, M. Wilke |
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Dokumenttyp: | Zeitschriftenartikel |
Veröffentlichungsform: | Verlagsliteratur |
Sprache: | Englisch |
Titel des übergeordneten Werkes (Englisch): | Contributions to mineralogy and petrology |
Jahr der Erstveröffentlichung: | 2022 |
Organisationseinheit der BAM: | 1 Analytische Chemie; Referenzmaterialien |
1 Analytische Chemie; Referenzmaterialien / 1.1 Anorganische Spurenanalytik | |
Veröffentlichende Institution: | Bundesanstalt für Materialforschung und -prüfung (BAM) |
Verlag: | Springer |
Jahrgang/Band: | 177 |
Ausgabe/Heft: | 8 |
Erste Seite: | 1 |
Letzte Seite: | 17 |
DDC-Klassifikation: | Naturwissenschaften und Mathematik / Chemie / Analytische Chemie |
Freie Schlagwörter: | Diffusion; Hydrated silicate melts; Isotopic fractionation; Stable isotopes |
Themenfelder/Aktivitätsfelder der BAM: | Chemie und Prozesstechnik |
Chemie und Prozesstechnik / Chemische Charakterisierung und Spurenanalytik | |
DOI: | 10.1007/s00410-022-01937-2 |
URN: | urn:nbn:de:kobv:b43-554496 |
Verfügbarkeit des Dokuments: | Datei für die Öffentlichkeit verfügbar ("Open Access") |
Lizenz (Deutsch): | Creative Commons - CC BY - Namensnennung 4.0 International |
Datum der Freischaltung: | 08.08.2022 |
Referierte Publikation: | Ja |
Datum der Eintragung als referierte Publikation: | 08.08.2022 |
Schriftenreihen ohne Nummerierung: | Wissenschaftliche Artikel der BAM |