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Showing 1 to 20 of 70 for “"Magma Chamber"”.
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Numerical simulations of magma chamber dynamics at Campi Flegrei, and associated seismicity, deformation and gravity changes
… by volcanic monitoring network and shallow magma processes is a crucial headway for the comprehension of volcanic processes and a more realistic evaluation of the associated hazard. This question is very relevant at Campi Flegrei, a volcanic quiescent caldera immediately north-west of Napoli …
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Quantifying magma recharge at Parinacota volcano, northern Chile (52 ka - recent): Insight from the Magma Chamber Simulator
The Magma Chamber Simulator (MCS; Bohrson et al., 2014) was used to produce new thermodynamic models that constrain and quantify recharge and fractional crystallization (RFC) processes for the Old Cone (OC; 52-20 ka; 56-66 wt.% SiO<sub>2</sub>) and Healing Flows (HF; >8 ka-recent; 58-64 wt.% …
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The Role of Cumulate Plagioclase Entrainment in the Steens Basalt, SE Oregon: Insights from the Magma Chamber Simulator
… of these giant plagioclase yields insight into magmatic processes like recharge, crustal assimilation, cumulate entrainment, and fractional crystallization. Because large and abundant plagioclase are found in other flood basalt provinces worldwide, these results could also enhance understanding …
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Petrogenetic Relationship of the Postcaldera Eruptions of Mount Mazama, Crater Lake, Oregon; Evolution of a Sub-volcanic Magma Chamber Following a Large Silicic Eruption
… formed a dome (Bacon et al., 2002). How magmatic systems evolve following a shallow, relatively large silicic eruption is the focus of this study. In situ geochemical analysis coupled with high-resolution textural images of plagioclase crystals in the four postcaldera volcanic edifices …
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3D and 4D Modeling of Ignimbrite Eruptions
<p>The need to model the Yellowstone magma chamber and other possible sites for ignimbrite eruption has been accelerated by the development of the areas surrounding the volcanoes. Early detection of eruptions is the most important aspect when trying to reduce casualties from an eruption. The magma …
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Exploring two-phase hydrothermal circulation at a seafloor pressure of 25 MPa: Application for EPR 9°50′N
… boundary conditions that represent a sub-axial magma chamber to explore the effects of permeability, maximum bottom temperature and system depth on the evolution of vent fluid temperature and salinity, and heat output. We also study the temporal and spatial variability in hydrothermal …
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The seismic attenuation structure of the East Pacific Rise
… been inferred to be the roof of a small axial magma chamber at about 1.6 km depth. A spectral method is used to estimate t*, a measure of the integrated attenuation along a wave path. Such a method asswnes that the dominant frequency-dependent component of propagation is intrinsic attenuation. …
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Giant Plagioclase in the Steens Basalt, SE Oregon: Cumulate Entrainment Revealed by Textural and In Situ Chemical Analysis
… of crystals in equilibrium with the erupted magma. In contrast, upper Steens plagioclase are more chemically zoned and frequently exhibit textural and isotopic disequilibrium consistent with the preservation of antecrystic material. Computational modeling provides further support to the …
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Probing the interior of an active volcano: Three-dimensional seismic tomography at Montserrat
Constraining the magmatic systems of active volcanoes is important for comprehending the mechanisms that drive magma supply. Particularly important are the geometry and characteristics of magma storage regions in the upper and middle crust, which can influence the style and time-scales of …
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Documenting the Origin of Compositional Diversity of Subduction Zone Magmatism, Alicudi, Aeolian Arc (Southern Tyrrhenian Sea, Italy) Using in situ Plagioclase Data
<p>Processes that generate magma compositional diversity are important to document because composition affects degree of explosivity, which impacts hazard mitigation. Magnesium to silicon rich magmas are produced by processes such as magma recharge, assimilation, and fractional crystallization …
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The CAFE Experiment : a joint seismic and MT investigation of the Cascadia Subduction System
… forms a column up to a conductor indicative of a magma chamber feeding Mt. Rainier. This feature also explains the disruption of the continental Moho found in the migrated image. Exploration of the assumption of smoothness implicit in the standard MT inversion provides tools that enable us to …
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The CAFE experiment : a joint seismic and MT investigation of the Cascadia subduction system
… forms a column up to a conductor indicative of a magma chamber feeding Mt. Rainier. This feature also explains the disruption of the continental Moho found in the migrated image. Exploration of the assumption of smoothness implicit in the standard MT inversion provides tools that enable us to …
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Petrogenetic Processes Characterizing the Mount Bachelor, Oregon Magmatic System: Open- versus Closed-System Processes
… with time, but a detailed assessment of magma chamber processes has not been conducted. To gain a more thorough understanding of the magmatic processes that have contributed to the observed compositional evolution, this study focuses on one of four eruptive episodes, specifically episode …
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An investigation into the formation of the lower Main Zone in the eastern limb of the Bushveld complex, South Africa
… and the Mg# decreases. The variations in magma compositions are attributed to interlayering of different lithologies which are the result of fractional crystallisation in the magma chamber. This is supported by linear trends of the major and trace element bivariant plots. The magmatic …
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Tertiary and carboniferous magmatism around Lundy Island and the outer Bristol Channel - a geophysical and geochemical perspective
… of magnetic susceptibility studies indicate that magma for the radial component was emplaced at shallow to moderate inclinations, suggesting a relatively shallow origin near to the western border of Lundy Island. The regional component was emplaced at shallow to sub-horizontalangles, suggesting …
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Petrology of the Gracefield pluton.
… to be 730°C. The temperature of the magma at the time of intrusion was somewhat higher. If the oxygen fugacity during the crystallization history of the early intrusive was close to that of the QFM buffer, the fugacity of water was between 302 and 1950 bars. The silica activity in the …
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The Foyers Granitic Complex and its aureole
… units are the products of a differentiating magma body at depth. A north easterly trending suite of microdiorite dykes cross cuts the complex. The complex was emplaced into Grampian Group psammites, after the cessation of Caledonian orogenesis, and developed an extensive thermal aureole, with …
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The petrology, geochemistry and structure of the plutonic rocks of the Oman ophiolite
… mantle at pressures of 20kB or more. The primary magmas generated (tholeiitic picrites, minimum MgO 14%) supplied a sub-oceanic spreading ridge magma chamber in which formed the layered mafic and ultramafic rocks of the Cumulate Sequence and the isotropic gabbros, diorites and trondhjemites of the …
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Magmatic processes that generated the rim andesites of Medicine Lake Volcano, N. California
… by fractional crystallization in a shallow magma chamber (~ 4 to 8 km). Petrologic evidence indicates pre-eruptive H20 contents of 2 to 4 wt.% H20 over a temperature range of 1070 to 900 C. Oxygen fugacity recorded in coexisting spinel and rhombohedral oxides varies from NNO (Nickel - Nickel …
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The Middle Fork Plutonic Complex: a plutonic association of coeval peralkaline and metaluminous magmas in the north-central Alaska Range
… and temporal relationships led to complex magmatic interactions. Calculated initial ⁸⁷Sr/⁸⁶Sr for gabbro and diorite group around 0.705 to 0.706. HB granites are heterogeneous, but fall mostly around 0.707 to 0.708. Hypersolvus syenites and AF granites form an isochron with initial …
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