|
Search over 100 encyclopedias and dictionaries: |
Research categories | Follow us on Twitter |
Research categories
View all topics in the newsView all reference sources at Encyclopedia.com |
|||
Magma Chamber
Magma chamberA magma chamber is a reservoir of molten rock that is the source of lava in a volcanic eruption. Magma chambers are typically located a few kilometers below the surface. A magma chamber is created by a mantle plume, or upwelling of heat from the earth's mantle. This delivers heat and molten rock upwards to the base of the crust . Because magma is less dense than solid rock, it will rise through fractures. Dissolved gases under pressure also help to force the magma upwards. If the migrating magma can no longer find a path upwards, it may gather into a reservoir and form a magma chamber. Continual migration of more magma into the chamber will cause the pressure within the chamber to increase. At some point, the magma chamber may not be able to contain the pressure and the magma, and it may breech. The magma is then driven upward through a conduit such as a volcanic neck or fissure , resulting in the eruption of the volcano . Sometimes, a magma chamber will experience a cessation in the influx of magma before it is able to release into a volcanic eruption. It this case, the magma may begin to cool and crystallize in place. As it does so, mineral crystals form and settle to the bottom while the remaining magma, depleted of the components that formed the initial minerals , pools at the top. Certain minerals will form first according to Bowen's reaction series , with crystallization becoming successively more silica rich. This process is known as fractional crystallization and results in a stratified igneous body, known as a layered intrusion. The Skaergaard intrusion in Greenland is a well known layered intrusion. See also Volcanic eruptions |
|
|
Cite this article
"Magma Chamber." World of Earth Science. 2003. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. "Magma Chamber." World of Earth Science. 2003. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1G2-3437800368.html "Magma Chamber." World of Earth Science. 2003. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3437800368.html |
|
magma chamber
magma chamber A region, postulated to exist below the Earth's surface, in which magma is received from a source region in the deep crust or upper mantle, stored, and from which it moves to the Earth's surface at the site of a volcano. The existence of ‘magma chambers’ is often invoked by geochemists to provide a location for processes such as fractional crystallization, because the chemistry of lavas is explicable only in terms of such processes. When magma moves rapidly from the chamber, as in a pyroclastic flow eruption, the unsupported chamber roof may collapse to produce a caldera at the surface. The diameter of the caldera can be used to estimate the diameter of the underlying magma chamber; diameters of up to 40 km are not uncommon for terrestrial subvolcanic magma chambers.
|
|
|
Cite this article
AILSA ALLABY and MICHAEL ALLABY. "magma chamber." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. AILSA ALLABY and MICHAEL ALLABY. "magma chamber." A Dictionary of Earth Sciences. 1999. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O13-magmachamber.html AILSA ALLABY and MICHAEL ALLABY. "magma chamber." A Dictionary of Earth Sciences. 1999. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O13-magmachamber.html |
|
magma chamber
magma chamber A region, postulated to exist below the Earth's surface, in which magma is received from a source region in the deep crust or upper mantle, stored, and from which it moves to the Earth's surface at the site of a volcano. When magma moves rapidly from the chamber, the unsupported chamber roof may collapse to produce a caldera at the surface.
|
|
|
Cite this article
MICHAEL ALLABY. "magma chamber." A Dictionary of Ecology. 2004. Encyclopedia.com. 31 May. 2012 <http://www.encyclopedia.com>. MICHAEL ALLABY. "magma chamber." A Dictionary of Ecology. 2004. Encyclopedia.com. (May 31, 2012). http://www.encyclopedia.com/doc/1O14-magmachamber.html MICHAEL ALLABY. "magma chamber." A Dictionary of Ecology. 2004. Retrieved May 31, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O14-magmachamber.html |
|
Search over 100 encyclopedias and dictionaries:
HighBeam™ Research, Inc. © Copyright 2012. All rights reserved.
The Encyclopedia.com advertising network includes:
