54 research outputs found
Characterization and Calibration of the CheMin Mineralogical Instrument on Mars Science Laboratory
Reaction overstepping and re-evaluation of peak P‒T conditions of the blueschist unit Sifnos, Greece: implications for the Cyclades subduction zone
Linking thermodynamic modelling, Lu–Hf geochronology and trace elements in garnet: new P–T–t
Pre-eruption recharge of the Bishop magma system
The 650 km3 rhyolitic Bishop Tuff (eastern California, USA), which is stratigraphically zoned with respect to temperatures of mineral equilibration, reflects a corresponding thermal gradient in the source magma chamber. Consistent with previous work, application of the new TitaniQ (Ti-in-quartz) thermometer to quartz phenocryst rims documents an ∼100 °C temperature increase with chamber depth at the time of eruption. Application of TitaniQ to quartz phenocryst cores, however, reveals lower temperatures and an earlier gradient that was less steep, with temperature increasing with depth by only ∼30 °C. In many late-erupted crystals, sharp boundaries that separate low-temperature cores from high-temperature rims cut internal cathodoluminescent growth zoning, indicating partial phenocryst dissolution prior to crystallization of the high-temperature rims. Rimward jumps in Ti concentration across these boundaries are too abrupt (e.g., 40 ppm across a distance of <10 µm) to have survived magmatic temperatures for more than ∼100 yr. We interpret these observations to indicate heating-induced partial dissolution of quartz, followed by growth of high-temperature rims (made possible by lowering of water activity due to addition of CO2) within 100 yr of the climactic 760 ka eruption. Hot mafic melts injected into deeper parts of the magma system were the likely source of heat and CO2, raising the possibility that eruption and caldera collapse owe their origin to a recharge event
Growth mechanism of snowball garnets from the Lukmanier Pass area (Central Alps, Switzerland): a combined ?CT/EPMA/EBSD study
The microarea composition of garnet and biotite from the Ji’an Group in Tonghua district and its significance as an indicator of metamorphicP-T-t path
H 2 O Content Measurement in Phengite by Secondary Ion Mass Spectrometry: A New Set of Reference Materials
Late Pan-African Fluid Infiltration in the Mühlig-Hofmann- and Filchnerfjella of Central Dronning Maud Land, East Antarctica
Garnet-biotite geothermometer and estimation of crystallization temperature of zoned garnets from metapelites: I. Reconstruction of thermal history of porphyroblast growth
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