2012年3月
Experiments on upward migration of a liquid-rich layer in a granular medium: Implications for a crystalline magma chamber
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
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- 巻
- 13
- 号
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1029/2011GC003994
- 出版者・発行元
- AMER GEOPHYSICAL UNION
We perform a series of experiments to investigate the situation in which a melt-rich layer formed by a magma intrusion ascends through a crystalline magma chamber. The initial condition is such that a heavier granular layer overlies a liquid layer. The particles consisting the upper granular layer are in a jammed state, and only the particles near the interface can move to form a dilated boundary layer. The dilated layer detaches from the upper granular layer, and forms downwelling plumes which drive a cellular convection within the liquid-rich layer. The convection erodes the upper granular layer, and the liquid-rich layer migrates upwards with time. This upward migration of the liquid-rich layer differs from the previously known mechanisms of liquid transport; permeable flow in which the liquid migrates at the Darcy velocity, the Stokes settling in which the individual particle settles, and diapirs formed by the Rayleigh-Taylor instability. We find that the velocity of the upward migration of the liquid-rich layer can be scaled by the volumetric flux of the liquid ascending through the narrow channel between the particles. The upward migration of the liquid-rich layer is faster than the Darcy velocity. In a mushy magma chamber whose crystals are in a jammed state, neither the Stokes settling nor the Rayleigh-Taylor instability can occur. We propose that the upward migration of the melt-rich layer observed in our experiments can become an efficient mechanism of melt transport in a crystalline magma chamber.
- リンク情報
- ID情報
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- DOI : 10.1029/2011GC003994
- ISSN : 1525-2027
- Web of Science ID : WOS:000301497600003