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Showing 1 to 20 of 34 for “"Partial Melt"”.
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The partial molar volume of carbon dioxide in peridotite partial melt at high pressure
The partial molar volume of CO2 (VCO2) in silicate melt was determined for a komatiite composition using high pressure sink/float experiments in a multi-anvil press. The density of the experimental melt at pressure was determined by observing sinking and floating of pure forsterite (Fo100) and 90% …
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Geochemical and petrological investigation into the magmatic system at Soufrière Hills Volcano, Montserrat.
… from a slower cooling vesiculating hybridised melt layer. Type C, are a composite of types A and types B, representing an interface between the types. Geochemical modelling shows that since the start of the current eruption that the dominant control on the range of enclave bulk compositions has …
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Seismic Tomography at Volcanic Rift Zones and Transpressional Plate Boundaries Askja Caldera and Macquarie Island
… System (GNSS), which is consistent with shallow melt accumulation. Seismic attenuation, a sensitive indicator of partial melt, was derived from a shallow local earthquake dataset to corroborate the presence of the shallow magma reservoir. A new 3-D model of absorption reveals a shallow …
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Petrogenesis of lavas from Volcano Azufre, Northern Chile: evidence for crustal input
… arcs globally, and the presence of a zone of partial melt, the Altiplano-Puna Magma Body (APMB), below the APVC as they could both have had a major effect on erupting lavas. Elemental concentration and isotope data are used here to examine the role that the APMB has had on the evolution of …
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Uranium-series isotope constraints on magma generation and differentiation in the central Oregon Cascades
… most primitive lavas suggest derivation by < 10% partial melting of a garnet-bearing mantle source. This source is interpreted to have experienced relatively minor modification by a slab-derived component, most likely via addition of a partial melt of subducted sediments. The 238U-230Th-226Ra …
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Carbon in Silicate Melt - Experimental Constraints and Applications for the Subduction Zone and Magma Ocean Carbon Cycles
… of CO2 solubility on natural hydrous rhyolitic melts. These studies are applicable to subduction zone settings of the Earth throughout its history. Carbon concentrations and speciation were measured using FTIR, and in the process, we determined absorption coefficients for the CO2 species …
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Pressure-driven instability in planetary stagnant lids
… a major role. In many cases this results in a partially molten mantle, known as a magma ocean. Both fully solid mantles and magma oceans are noted for their complex fluid dynamics, in particular involving the convection of fluids with strongly temperature-dependent viscosities. Because of the …
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Local Earthquake Tomography at Mt. Pinatubo, Philippines
… of mostly competent rock, which may contain partial melt.
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Mapping, petrological and geochemical explorations of the Massabesic Gneiss Complex in New Hampshire
… show evidence of compression and decompression melting episodes in which muscovite and biotite dehydration reactions contribute to magmas that the mobilize and accumulate to produce the migmatite and rock textures observed during the mapping phase of this project. Geochemically the …
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Seismic Studies of Subducted Lithosphere Beneath Fiji: Evidence for a Petrologic Anomaly
… of these candidates and the strong effect of partial melt on VS, volatiles in the form of hydrous phases or melt induced by dehydration are not consistent with observed reductions in V P and VS. Meanwhile, metastable olivine remains a viable candidate. As a cold slab passes below the 410-km …
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Heat flow and heat production studies in North Dakota
… is narrow (28 km) implying a shallow depth to partially molten lower crust or upper mantle. When used with experimental petrologic data for peridotite in the presence of excess water, temperature calculations suggest that a partial melt zone begins approximately at the depth of the Moho (45 to …
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Geophysical imaging methods for analysis of the Krafla Geothermal Field, NE Iceland
… a gas-filled fracture zone, and a possible partial melt region based on the P-wave, S-wave, and Vp/Vs ratio anomalies in the velocity model. Synthetic modeling of the relationship between the resistivity and velocity models demonstrated the complexities of integrating two data sets with …
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Fluid inclusions: evidence for a counterclockwise P-T trajectory in the Central Maine terrane of South-Central Massachusetts
… within quartz inclusions in garnets found in partial melt leucosomes, and in quartz grains within migmatites. Fluid inclusions within the quartz inclusions indicate trapping conditions of 650-700°C at pressures below 5 kbar. Other CO₂ fluid inclusions from matrix quartz yield isochores which …
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Determining the upper mantle seismic structure beneath the northern transantarctic mountains, Antarctica, form regional p- and s-wave tomography
… low velocities are interpreted as regions of partial melt and buoyancy-driven upwelling, connected by a broad region of slow (presumably warm) upper mantle associated with Cenozoic extension along the TR. Dynamic topography estimates based on the imaged S-wave velocity perturbations are …
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Enhanced imaging of deep lithospheric and shallow near surface structures through innovations in seismic interferometry and array processing.
… velocity gradient at the LAB consistent with partial melt or volatile enrichment in the asthenosphere. The second study applies teleseismic P-wave coda autocorrelogram imaging to broadband stations across 4 seismic networks in northeastern North America to investigate upper mantle …
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Magmatic processes recorded in crystals from intraplate basalt volcanoes, Kaikohe-Bay of Islands volcanic field, New Zealand
… indicating some are antecrysts formed in melts fractionated from plutonic basaltic forerunners, while others are true xenocrysts from greywacke basement and/or Miocene arc volcanics. The cores of clinopyroxene phenocrysts variously grew in a magma comparable to that of the host rock …
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Deformation and its surface expression in stressed planetary materials
… investigate two-phase deformation, where a partial melt phase is present between grains of solid materials such as olivine (Chapter 2) or ice (Chapter 3). Chapter 2 finds that in partially molten rocky materials, microstructural melt aligns parallel to the maximum applied stress direction …
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The petrology and geochemistry of Precaldera Magmas, Long Valley Caldera, Eastern California
… basaltic magmas were generated from a lherzolite partial melt modified by minor crystal fractionation (limited fractionation due to their high incompatible element content) and contamination by older sialic rocks or their derivatives (represented by granitic inclusions, quartz xenocrysts, and …
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The seismic attenuation structure of the East Pacific Rise
… of 25-50 require only very small fractions of partial melt. The attenuation observations thus place constraints on the dimensions of the axial magma chamber and strongly suggest that the thickness of the region containing more than a few percent of partial melt is no more than 1 km.
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Seismic and magnetic constraints on the structure of upper oceanic crust at fast and slow spreading ridges
… the EPR reveal it to be a thin (<100 m) body of partial melt. These characteristics have important implications for melt availability and transport within the cycle of eruption and replenishment. A genetic algorithm-based seismic waveform inversion technique is developed and applied to on- and …
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