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Extrusive rocks are... extruded... onto the surface as the lava that we all think of. It cools fairly quickly, into rocks with fairly small crystals (might need a magnifying lens to see them). The exact chemistry of the parent magma will determine the type of rock. Oceanic volcanoes are generally basaltic (mafic or ultramafic), continental are generally granitic (felsic or intermediate). They're put down in "relatively thin" layers.
Intrusive rocks cool for thousands of years beneath the surface in huge plutons or batholyths. This allows them to grow very large crystals (easily seen by the unaided eye). These intrusive rocks are almost always granitic-type rock.
Wiki User
∙ 12y ago
Wiki User
∙ 12y agoWiki User
∙ 13y agoAn extrusion is the forcing out of one material from another. An intrusion is the opposite where one material is forced into / inside or in between another.
Wiki User
∙ 12y agointrusion - intrusion is when magma cools down inside Earth.
extrusion - extrusion is when lava cools down on Earth.
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How are faults intrusions and extrusions similar?
by looking at it
What do scientist use igneous intrusions and extrusions for?
they use it for finding new thing
How do scientists date sedimentary rock?
They date the igneous intrusions and extrusions near the sedimentary rock layers.
Why arent fossils found in extrusions and intrusions?
Because extrusion and intrusions are melted magma that hasn't reached the earth's surface and the hot magma can't just pick up fossils that are already in place.
What evidence would a scientists use to determine the absolute age of a fossil found in sedimentary rock?
The Igneous intrusions and extrusions near sedimentary layers.
Intrusions of the igneous rock are younger or older than the rock layers beneath and surrounding them?
they are younger and extrusions are older. they are younger because the surrounding rock layers had to have been there first in order for it to appear. :)
What are three types of clues to the relative age of rock layers other than the law of superposition?
To determine relative age, geologists also study extrusions and intrusions of igneous rock, faults, gaps in the geologic record, and inclusions.
Can I decide the thickness of the wall when using custom aluminum extrusions?
Aluminum, plastic, and copper are most suitable for extrusions. Thickness can be determined with aluminum extrusions.
What is the definition of extrusions?
extruszion
Where are extrusions found?
where are egneos rocks found
What do extrusions look like?
it look like a magam
What are aluminum extrusions used for?
Aluminum extrusions are used to turn aluminum alloy into other materials for cross sectional profiles. It is extracted from other metals containing aluminum and squeezed out.
