From Simple English Wikipedia, the free encyclopedia
Magma
is the melted
rock
under the ground.
[1]
The liquid rock may have solid bits mixed in with it, and volcanic gas.
There are different types of magma. One is called
felsic
magma. Felsic magma is thick and has
silica
minerals
. It mostly makes light-coloured rocks. Another type is called
mafic
magma, which is runny and has less silica. It usually makes dark-coloured rocks. Magmas can be intermediate between both types.
Magma may become solid by cooling slowly below the surface. This makes "plutonic" rocks such as
granite
. When magma comes out from the ground in a
volcano
it is called
lava
. Lava cools quickly, and forms other kinds of rock such as
basalt
.
Magma is produced by melting of the Earth's
mantle
or the
crust
. It happens at
tectonic
settings, such as
subduction
zones, continental
rift zones
,
[2]
mid-ocean ridges
and
hotspots
.
Melted material from the mantle and crust moves up through the crust and collects in
magma chambers
.
[3]
[4]
When they come up through the crust, magmas may feed a
volcano
and come out as lava. But they may solidify underground to form an
intrusion
(magma which cools and becomes solid).
[5]
Intrusions eventually cool down and become
igneous dikes
or
sills
.
The study of magma is usually done in lava flows. However, magma was found under the ground three times in
geothermal drilling projects
—twice in Iceland and once in Hawaii.
[6]
[7]
[8]
[9]
- ↑
Bowen, Norman L. (1947).
"Magmas"
.
Geological Society of America Bulletin
.
58
(4): 263.
doi
:
10.1130/0016-7606(1947)58[263:M]2.0.CO;2
.
ISSN
0016-7606
.
- ↑
Foulger, G.R. (2010).
Plates vs. Plumes: A Geological Controversy
. Wiley?Blackwell.
ISBN
978-1-4051-6148-0
.
- ↑
Detrick, R. S.; Buhl, P.; Vera, E.; Mutter, J.; Orcutt, J.; Madsen, J.; Brocher, T. (1987). "Multi-channel seismic imaging of a crustal magma chamber along the East Pacific Rise".
Nature
.
326
(6108): 35?41.
Bibcode
:
1987Natur.326...35D
.
doi
:
10.1038/326035a0
.
ISSN
0028-0836
.
S2CID
4311642
.
- ↑
Sparks, R. Stephen J.; Cashman, Katharine V. (2017). "Dynamic Magma Systems: Implications for Forecasting Volcanic Activity".
Elements
.
13
(1): 35?40.
doi
:
10.2113/gselements.13.1.35
.
ISSN
1811-5209
.
- ↑
McBirney, A.R.; Noyes, R.M. (1979-08-01).
"Crystallization and Layering of the Skaergaard Intrusion"
.
Journal of Petrology
.
20
(3): 487?554.
Bibcode
:
1979JPet...20..487M
.
doi
:
10.1093/petrology/20.3.487
.
ISSN
0022-3530
.
- ↑
Scientists' Drill Hits Magma: Only Third Time on Record
, UC Davis News and Information, June 26, 2009.
- ↑
Magma Discovered in Situ for First Time
. Physorg (December 16, 2008)
- ↑
Puna Dacite Magma at Kilauea: Unexpected Drilling Into an Active Magma Posters
Archived
2011-06-06 at the
Wayback Machine
, 2008 Eos Trans. AGU, 89(53), Fall Meeting.
- ↑
Teplow, William; Marsh, Bruce; Hulen, Jeff; Spielman, Paul; Kaleikini, Mike; Fitch, David; Rickard, William (2009).
"Dacite Melt at the Puna Geothermal Venture Wellfield, Big Island of Hawaii"
(PDF)
.
GRC Transactions
.
33
: 989?994
. Retrieved
8 February
2021
.
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