Magma Processes and Composition Changes

The video tutorial explains four processes that cause magmas to change over time: assimilation, magma mixing, fractional crystallization, and partial melting. Assimilation involves magma incorporating surrounding rock, making it more felsic. Magma mixing occurs when different magma types merge, altering their composition. Fractional crystallization involves the cooling and crystallization of minerals, changing the magma's chemistry. Partial melting occurs when heat causes the lithosphere to melt, forming new magma that is more felsic. Overall, these processes often result in magma becoming more felsic over time.

What is the primary focus of the introduction section?

• The role of temperature in magma formation

• The chemical composition of magma

• An overview of four processes that change magmas

• The detailed process of magma mixing

What happens during the assimilation process?

• Magma incorporates surrounding rock, becoming more felsic

• Magma splits into smaller blobs

• Magma loses its chemical properties

• Magma cools and forms crystals

Which process involves the incorporation of surrounding rock into magma?

• Assimilation

• Partial melting

• Fractional crystallization

• Magma mixing

How does magma mixing affect the composition of magma?

• It causes the magma to solidify

• It alters the composition based on the types of magma involved

• It makes the magma more mafic

• It has no effect on the magma's composition

What is the effect of magma mixing on intermediate and mafic magmas?

• Mafic becomes more felsic

• Intermediate becomes more felsic

• Both remain unchanged

• Intermediate becomes more mafic

What is the result of fractional crystallization?

• Minerals crystallize and sink, changing the magma's composition

• Magma becomes more mafic

• Magma becomes more felsic

• Magma remains unchanged

During fractional crystallization, what happens to the denser mineral crystals?

• They float to the top

• They dissolve back into the magma

• They sink to the bottom

• They evaporate

What triggers partial melting in the lithosphere?

• The movement of tectonic plates

• The presence of water

• An increase in temperature from a mantle plume

• A decrease in pressure

What is the primary outcome of partial melting?

• Creation of more mafic magma

• Formation of new minerals

• Production of more felsic magma

• Complete solidification of magma

Which process is most likely to result in a magma becoming more felsic over time?

• Assimilation

• Magma mixing

• Partial melting

• Fractional crystallization