Plagioclase zonation styles in hornblende gabbro inclusions from Little Glass Mountain, Medicine Lake volcano, California: implications for fractionation mechanisms and the formation of composition gaps
Article Abstract:
The rhyolite of Little Glass Mountain containing quenched andesite liquid inclusions and cumulative hornblende gabbro helps to understand the process of fractional crystallization and the generation of composition gap. The host rhyolite lava is generated by a parental andesite magma. The inward solidification of a crystallizing boundary layer, followed by melt extraction and accumulation of interstitial liquid, could be the mechanism of fractional crystallization that produced the host rhyolite lava. This explains the composition gap between parental andesite and rhyolite magma compositions.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1996
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Mid-Pleistocene lavas from the Seguam volcanic center, central Aleutian arc: closed-system fractional crystallization of a basalt to rhyodacite eruptive suite
Article Abstract:
The potassium-argon dating done on the mid-Pleistocene Turf Point Formation (TPF) suite showed that Seguam Island in the Aleutians was formed on an extended arc crust. TPF petrology revealed that lavas range from basalt to rhyodacite and are generally tholeiitic. The mineral composition and texture of porphyritic basalt and basaltic andesite lavas exhibited equilibrium crystallization without the presence of assimilation or open-system mixing. The intra-arc extension of the island not only modified the crust structure but also spread heat and density in the lithosphere.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1992
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Petrologic and experimental evidence for the movement and heating of the pre-eruptive Minoan rhyodacite (Santorini, Greece)
Article Abstract:
A study on the evolution of magma storage system for the rhyodacitic magma shows the possibility that rhyodacite went through a heating process and polybaric migration within the crust which could have been due to intrusion of mafic magma. Petrologic assessment of the Minoan magmas were reviewed and results were supplemented with data regarding both the mafic scoria and rhyodacite. Hydrothermal experiments were also conducted for a better understanding of the pre-eruptive histories of the two magmas.
Publication Name: Contributions to Mineralogy and Petrology
Subject: Earth sciences
ISSN: 0010-7999
Year: 1999
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- Abstracts: Active continental rifting in southern Baja California, Mexico: implications for plate motion partitioning and the transition to seafloor spreading in the Gulf of California
- Abstracts: Paleomagnetism and 40Ar/39Ar geochronology of gabbro sills at Mariscal Mountain anticline, southern Big Bend National Park, Texas: implications for the timing of Laramide tectonism and vertical axis rotations in the southern Cordilleran orogenic belt
- Abstracts: Geochemical evolution of Jurassic diorites from the Bristol Lake region, California, USA, and the role of assimilation