Fluid and melt inclusion evidence for the origin of idiomorphic quartz crystals in topaz-bearing granite from the Salmi batholith, Karelia, Russia
| Autor: | T.F Scherbakova, M Poutiainen |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
010504 meteorology & atmospheric sciences
Geochemistry Mineralogy Geology Solidus Liquidus engineering.material 010502 geochemistry & geophysics 01 natural sciences Topaz Geochemistry and Petrology Batholith engineering Fluid inclusions Inclusion (mineral) Quartz 0105 earth and related environmental sciences Melt inclusions |
| Zdroj: | Lithos. 44:141-151 |
| ISSN: | 0024-4937 |
| DOI: | 10.1016/s0024-4937(98)00052-8 |
| Popis: | Idiomorphic quartz crystals in topaz-bearing granite from the Salmi batholith contain primary inclusions of silicate melt and abundant mostly secondary aqueous fluid inclusions. Microthermometric measurements on melt inclusions give estimates for the granite solidus and liquidus of 640–680°C and 770–830°C, respectively. Using published solubility models for H2O in granitic melts and the obtained solidus/liquidus temperatures from melt inclusions, the initial water concentration of the magma is deduced to have been approximately 3 wt.% and the minimum pressure about 2 kbar. At this initial stage, volatile-undersaturation conditions of magma were assumed. These results indicate that the idiomorphic quartz crystals are magmatic in origin and thus real phenocrysts. During subsolidus cooling and fracturing of the granite, several generations of aqueous fluid inclusions were trapped into the quartz phenocrysts. The H2O inclusions have salinities and densities of 1–41 wt.% NaCl eq. and 0.53–1.18 g/cm3, respectively. |
| Databáze: | OpenAIRE |
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