Chapter 6 Flashcards
What is magma?
Magma is the parent material of igneous rocks, consisting of molten rock that contains solid crystalline material.
What are basaltic igneous rocks?
Basaltic igneous rocks are rich in dark silicate minerals and calcium-rich plagioclase feldspar, which gives them a dark color.
What are granite and rhyolite extrusive rocks?
Granite and rhyolite extrusive rocks are mostly light-colored silicate minerals, primarily quartz and potassium feldspar.
What are andesitic igneous rocks?
Andesitic igneous rocks have a composition that is between basaltic and granitic rocks.
How is the composition of magma ranked?
The composition of magma is ranked by silicate content as follows: Basaltic (mafic) is rich in dark silicates; Andesitic (Intermediate) is between basaltic and granitic; Granitic/Rhyolitic (felsic) is rich in light silicates.
Where is basaltic magma generated?
Basaltic magma results from the partial melting of the upper mantle.
Where is granitic magma generated?
Granitic magma results from the melting of the continental crust.
What factor determines how magma erupts?
Viscosity and Gas content.
What is the difference between Basaltic(mafic), Granitic/Rhyolitic(Felsic) and Andesitic(intermediate) magmas?
Basaltic have the lowest silica, Gas content and highest temperature erupt.
Granitic&Rhyolitic highest silica, Gas contents&lowest temperature erupts.
Andesitic:Characteristic between Basaltic and Granitic.
Where is magma generated?
Basaltic (Mafic) & Granitic Rhyolitic (felsic).
Where is magma generated?
Basaltic (Mafic) & Granitic Rhyolitic (felsic).
What is Viscosity?
Measure a fluid’s resistance to flow.
Extra note: higher viscosity leads to explosive eruptions.
What is the Gas content?
Is the amount of dissolved gases in magma.
Why is basaltic an effusive eruption and Rhyolitic have an explosive eruption.
Basaltic have a low gas content and Rhyolitic are highly viscous with high gas content.
