Mafic magmas are low in silica and typically have a higher percentage of iron and magnesium. This composition results in less viscous magmas that flow more easily and allow gas to escape more easily. As a result, eruptions from mafic magmas are generally less explosive and less violent compared to felsic to intermediate magmas.

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Mafic Magmas

Question 19

Multiple Choice

Mafic magmas

A) May contain up to about 75 percent SiO₂ by weight.
B) Are viscous and do not flow easily.
C) Tend to inhibit passage of gas that tries to escape through it.
D) Result in less violent eruptions than felsic to intermediate magmas.

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