Melt inclusions and crystal-liquid separation in rhyolitic magma of the Bishop Tuff
Article Abstract:
Crystals and liquids in silicic magma separate during the crystallization of plinian phenocrysts. The uranium, barium, strontium and europium concentrations support the separation process that occured in the rhyolitic magma. The uranium concentration in the melt inclusions must have a minimum amount of 33% by weight for fractional crystallization but only 17% is detected in the plinian pumice sample. In addition, uranium concentration in matrix glass must be higher than in melt inclusions but the opposite is observed in the phenocrysts.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1992
User Contributions:
Comment about this article or add new information about this topic:
Time scales of large volume silicic magma systems: Sr isotopic systematics of phenocrysts and glass from the Bishop Tuff, Long Valley, California
Article Abstract:
An analysis of the time scales of magmatic processes is presented. The analysis tests initial Sr isotopic compositions of glass and mineral separates taken from the Bishop Tuff in Long Valley, CA. It is shown that a substantial isotopic heterogeneity exists. The heterogenous characteristic is exhibited between eruptive units and between glass and phenocryst stages of each unit. Variations were generated by magmatic processes.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1993
User Contributions:
Comment about this article or add new information about this topic:
Pre-ore hydrothermal alteration in an unconformity-type uranium deposit
Article Abstract:
The changes in the hydrothermal conditions causing unconformity-type uranium deposit are due to substitution of intense chlorite with metamorphic mineral assemblages. The stages of pre-ore alteration include the changing of muscovite to mica having high octahedral occupancy and small interlayer content, substitution of the altered muscovite by Mg-rich serpentine and clinochlore and further substitution by Fe-rich chlorite.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1995
User Contributions:
Comment about this article or add new information about this topic:
- Abstracts: Origin and differentiation of picritic arc magmas, Ambae (Aoba), Vanuatu. Phase equilibria constraints
- Abstracts: Ridge axis deformation and coeval melt migration within layer 3 gabbros: evidence from the Lizard Complex, U.K
- Abstracts: Phase relations of osumilite and dehydration melting in pelitic rocks: a simple thermodynamic model for the KFMASH system
- Abstracts: Implications from inclusions in topaz for greisenisation and mineralisation in the Hensbarrow topaz granite, Cornwall, England
- Abstracts: Patterns and consequences of interspecific competition in natural communities: a review of field experiments with plants