Changes

[[File:lighterstill.jpg]][[File:DevilsTower200.jpg|frame|<center>A well-known example of an intrusion is [http://en.wikipedia.org/wiki/Devils_Tower Devils Tower</center>]]]

[[File:lighterstill.jpg]][[File:DevilsTower200.jpg|frame|<center>A well-known example of an intrusion is [https://en.wikipedia.org/wiki/Devils_Tower Devils Tower</center>]]]

==Origin==

==Origin==

[https://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English], from Anglo-French, from Medieval Latin ''intrusion''-, ''intrusio'', from [[Latin]] ''intrudere''

[https://nordan.daynal.org/wiki/index.php?title=English#ca._1100-1500_.09THE_MIDDLE_ENGLISH_PERIOD Middle English], from Anglo-French, from Medieval Latin ''intrusion''-, ''intrusio'', from [[Latin]] ''intrudere''

*[http://en.wikipedia.org/wiki/15th_century 15th Century]

*[https://en.wikipedia.org/wiki/15th_century 15th Century]

==Definitions==

==Definitions==

*1: the [[act]] of wrongfully entering upon, seizing, or taking [[possession]] of the [[property]] of another

*1: the [[act]] of wrongfully entering upon, seizing, or taking [[possession]] of the [[property]] of another

*2: the forcible entry of molten rock or [http://en.wikipedia.org/wiki/Magma magma] into or between other rock formations

*2: the forcible entry of molten rock or [https://en.wikipedia.org/wiki/Magma magma] into or between other rock formations

==Description==

==Description==

An '''intrusion''' is liquid rock that forms under [[Earth]]'s [[surface]]. [http://en.wikipedia.org/wiki/Magma Magma] from under the surface is slowly pushed up from deep within the earth into any cracks or spaces it can find, sometimes pushing existing country rock out of the way, a [[process]] that can take millions of years. As the rock slowly cools into a solid, the different parts of the magma crystallize into [[minerals]]. Many [[mountain]] ranges, such as the [http://en.wikipedia.org/wiki/Sierra_Nevada_(U.S.) Sierra Nevada] in California, are formed mostly by intrusive rock, large granite (or related rock) formations.

An '''intrusion''' is liquid rock that forms under [[Earth]]'s [[surface]]. [https://en.wikipedia.org/wiki/Magma Magma] from under the surface is slowly pushed up from deep within the earth into any cracks or spaces it can find, sometimes pushing existing country rock out of the way, a [[process]] that can take millions of years. As the rock slowly cools into a solid, the different parts of the magma crystallize into [[minerals]]. Many [[mountain]] ranges, such as the [https://en.wikipedia.org/wiki/Sierra_Nevada_(U.S.) Sierra Nevada] in California, are formed mostly by intrusive rock, large granite (or related rock) formations.

Intrusions are one of the two ways [http://en.wikipedia.org/wiki/Igneous_rock igneous rock] can form; the other is extrusive, that is, a [http://en.wikipedia.org/wiki/Types_of_volcanic_eruptions volcanic eruption] or similar event. Technically speaking, an intrusion is any formation of intrusive igneous rock; rock formed from magma that cools and solidifies within the [http://en.wikipedia.org/wiki/Earth's_crust crust of the planet]. In contrast, an extrusion consists of [http://en.wikipedia.org/wiki/Extrusive_(geology) extrusive rock]; rock formed above the surface of the crust.

Intrusions are one of the two ways [https://en.wikipedia.org/wiki/Igneous_rock igneous rock] can form; the other is extrusive, that is, a [https://en.wikipedia.org/wiki/Types_of_volcanic_eruptions volcanic eruption] or similar event. Technically speaking, an intrusion is any formation of intrusive igneous rock; rock formed from magma that cools and solidifies within the [https://en.wikipedia.org/wiki/Earth's_crust crust of the planet]. In contrast, an extrusion consists of [https://en.wikipedia.org/wiki/Extrusive_(geology) extrusive rock]; rock formed above the surface of the crust.

Intrusions vary widely, from mountain-range-sized [http://en.wikipedia.org/wiki/Batholith batholiths] to thin veinlike fracture fillings of [http://en.wikipedia.org/wiki/Aplite aplite] or [http://en.wikipedia.org/wiki/Pegmatite pegmatite]. When exposed by [[erosion]], these cores called batholiths may occupy huge areas of Earth's surface. Large bodies of magma that solidify underground before they reach the surface of the crust are called [http://en.wikipedia.org/wiki/Pluton plutons].

Intrusions vary widely, from mountain-range-sized [https://en.wikipedia.org/wiki/Batholith batholiths] to thin veinlike fracture fillings of [https://en.wikipedia.org/wiki/Aplite aplite] or [https://en.wikipedia.org/wiki/Pegmatite pegmatite]. When exposed by [[erosion]], these cores called batholiths may occupy huge areas of Earth's surface. Large bodies of magma that solidify underground before they reach the surface of the crust are called [https://en.wikipedia.org/wiki/Pluton plutons].

Coarse-grained intrusive igneous rocks that form at depth within the earth are called [http://en.wikipedia.org/wiki/Abyssal abyssal] while those that form near the surface are called [http://en.wikipedia.org/wiki/Hypabyssal hypabyssal]. Intrusive structures are often [[classified]] according to whether or not they are parallel to the [http://en.wikipedia.org/wiki/Stratum bedding planes] or [http://en.wikipedia.org/wiki/Foliation_(geology) foliation] of the country rock: if the intrusion is parallel the body is concordant, otherwise it is discordant.

Coarse-grained intrusive igneous rocks that form at depth within the earth are called [https://en.wikipedia.org/wiki/Abyssal abyssal] while those that form near the surface are called [https://en.wikipedia.org/wiki/Hypabyssal hypabyssal]. Intrusive structures are often [[classified]] according to whether or not they are parallel to the [https://en.wikipedia.org/wiki/Stratum bedding planes] or [https://en.wikipedia.org/wiki/Foliation_(geology) foliation] of the country rock: if the intrusion is parallel the body is concordant, otherwise it is discordant.

[[Category: Earth Science]]

[[Category: Earth Science]]