نتایج جستجو برای: magma flow
تعداد نتایج: 488709 فیلتر نتایج به سال:
Ground deformation often precedes volcanic eruptions, and results from complex interactions between source processes and the thermomechanical behaviour of surrounding rocks. Previous models aiming to constrain source processes were unable to include realistic mechanical and thermal rock properties, and the role of thermomechanical heterogeneity in magma accumulation was unclear. Here we show ho...
The emplacement of the Mesoproterozoic Götemar Pluton into Paleoproterozoic granitoid host rocks of the Transscandinavian Igneous Belt is re-examined by microfabric analysis, including cathodoluminescence microscopy. Field data on the pluton-host rock system are used to strengthen the model. The Götemar Pluton, situated on the Baltic Shield of SE Sweden, is a horizontally zoned tabular structur...
The Campanian Ignimbrite is a 4200 km trachyte^phonolite pyroclastic deposit that erupted at 39 3 0 1ka within the Campi Flegrei west of Naples, Italy. Here we test the hypothesis that Campanian Ignimbrite magma was derived by isobaric crystal fractionation of a parental basaltic trachyandesitic melt that reacted and came into local equilibrium with small amounts (5^10 wt%) of crustal rock (ska...
We utilize a theoretical analysis of the generation, ascent, intrusion and eruption of basaltic magma on the Moon to develop new insights into magma source depths, supply processes, transport and emplacement mechanisms via dike intrusions, and effusive and explosive eruptions. We make predictions about the intrusion and eruption processes and compare these with the range of observed styles of m...
The mechanical conditions for a volcanic eruption to occur are conceptually simple: a magma-driven fracture (normally a dyke) must be able to propagate from the source to the surface. The mechanics of small to moderate (eruptive volumes less than 10 km 3 ) is reasonably well understood, whereas that of large eruptions (eruptive volumes of 10-1000 km 3 ) is poorly understood. Here I propose that...
Introduction: Prior to the discovery of H2O dissolved in the picritic lunar glass beads [1], models for the eruption of lunar picritic magmas involved both a column of melt extending deep into the lunar mantle, and a gas-assisted lift of the magma to achieve explosive eruption [2,3,4,5]. In a H-free moon, first gas phase formation would have involved the oxidation of reduced C (graphite) to pro...
For those who remember the classic disaster-docudrama Supervolcano (BBC-Discovery Channel 2005), the adjective “eruptible” is likely to ring a bell. Set in the near future and generally quite scientifically literate, the movie envisions volcanologists trying desperately to evaluate the near-term threat posed by the giant Yellowstone magmatic system. At the heart of their mission, and of the dra...
the miocene pyroxene andesite lava flows are exposed in southeastern edge of urumieh dokhtar magmatic assemblage in iran. the hypocrystalline andesite in parts contain conspicuous co-magmatic igneous enclaves which are dark grey and occur mostly as spherical and occasionally as ribbon shapes with some showing chilled margins. petrographic study shows that the ribbon type enclaves have been form...
Deep long-period events (DLP events) or deep low-frequency earthquakes (deep LFEs) are deep earthquakes that radiate low-frequency seismic waves. While tectonic deep LFEs on plate boundaries are thought to be slip events, there have only been a limited number of studies on the physical mechanism of volcanic DLP events around the Moho (crust-mantle boundary) beneath volcanoes. One reasonable mec...
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