منابع مشابه
The Boycott effect in magma chambers
[1] We investigate the plausibility of the stratified Boycott effect as a source of layering in magma chambers. Crystal settling within the magma chamber will generate buoyant fluid near the sloping sidewalls whose vertical ascent may be limited by the ambient stratification associated with vertical gradients in SiO2. The resulting flow may be marked by a layered structure, each layer taking th...
متن کاملCrystal sizes in evolving silicic magma chambers
Crystal size distributions (CSDs) of quartz and zircon phenocrysts in individual pumice clasts from several voluminous ash-flow tuffs provide a quenched snapshot view of conditions in preclimactic magma chambers. A common feature of these CSDs is a concavedown, lognormal shape, in contrast to the reported linear CSDs in more mafic systems. This feature is interpreted to be a general result of s...
متن کاملSlow Control for Micromegas and Drift Chambers
A new spectrometer is being built for the COMPASS particle physics experiment at CERN. Saclay is in charge of the construction and the operation of two types of gaseous detectors: Micromegas microstrip detectors and Drift chambers [1], [2]. The operation of the detectors requires the slow control of high voltages and currents, and of the thresholds for the Front-End. This control system has bee...
متن کاملOn the evolution of large ultramafic magma chambers and timescales for flood basalt eruptions
[1] Large igneous provinces are characterized by magmatic activity on two distinct timescales. While these provinces have total active lifetimes of order 10–30 Ma, most of the erupted volume is emplaced within 1 Ma in many cases. The longer timescale is consistent with plume or tectonic models for mantle melting responsible for flood volcanism, but the shorter “main stage” timescale is enigmati...
متن کاملGravity Evidence for Extinct Magma Chambers on Mars: Tyrrhena Patera and Hadriaca Patera
The Mars Global Surveyor mission has vastly improved our knowledge of the topography and gravity of Mars [1,2,3], permitting detailed geophysical modeling of subsurface structures such as magma chambers for the first time. I have recently presented a gravity model for Syrtis Major [4] and showed that the gravity data requires the presence of a buried, high-density body. The spatial association ...
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ژورنال
عنوان ژورنال: Nature
سال: 2012
ISSN: 0028-0836,1476-4687
DOI: 10.1038/491677a