Abstract
Silicate melt inclusions were investigated in quartz phenocrysts of an iron-rich peralkaline rhyolite dike using high temperature microthermometry and scanning electron microscopy (SEM). A very low incipient melting temperature of about 500 °C indicates addition of a few percent of fluorine to the magmatic volatile phase. Volatile saturation conditions of magma genesis were assumed. The following data were obtained on the initial conditions of magma crystallization: liquids temperature, 750-830 °C; upper limit of pressure, 2-1 kbar; upper limit of magma water content, 6-4 wt %. SEM analysis of melt inclusions revealed an ongonite-rhyolite composition with an evolutionary trend from alkaline potassium-sodium to peralkaline perpotassic composition. The characteristic potassium enrichment of peralkaline magmatism in the Arabian-Nubian Shield was confirmed in the Nahal Shlomo area. It was shown that high SiO2 contents of melt inclusions were partly connected with host-quartz effect on SEM analysis and with partial enrichment of melt inclusions in SiO2 during heating experiments.
Original language | English |
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Pages (from-to) | 365-376 |
Number of pages | 12 |
Journal | Neues Jahrbuch Fur Mineralogie, Monatshefte |
Issue number | 8 |
State | Published - 1 Dec 1996 |
Keywords
- Melt inclusions
- Quartz phenocrysts
- Rhyolite dike
ASJC Scopus subject areas
- Geochemistry and Petrology