Igneous Petrology 1

Which of the following is NOT a volatile component found in magma?

• Water vapor

• Carbon dioxide

• Silicon dioxide

• Sulphur dioxide

Which type of magma is characterized by low viscosity and high temperatures?

• Rhyolitic

• Andesitic

• Basaltic

• Granite

Where is andesitic magma most likely to be found?

• Mid-ocean ridges

• Hot spots

• Subduction zones

• Continental interiors

What type of magma has a silica content greater than 65%?

• Basaltic

• Andesitic

• Rhyolitic

• Mafic

Which process describes the melting of mantle rock due to a decrease in pressure?

• Partial melting

• Decompression melting

• Flux melting

• Crystallization

What is an example of decompression melting?

• Melting of mantle peridotite

• Subduction zone magmatism

• Upwelling mantle material at mid-ocean ridges

• Formation of granite

Which process involves the addition of volatiles to lower the melting point of rocks?

• Partial melting

• Decompression melting

• Flux melting

• Fractional crystallization

What type of igneous rock is formed from the slow cooling of magma beneath the Earth’s surface?

• Extrusive

• Volcanic

• Intrusive

• Pyroclastic

Which of the following is an example of an intrusive igneous rock?

• Basalt

• Rhyolite

• Andesite

• Granite

What type of igneous rock texture is characterized by crystals that are too small to be seen without magnification?

• Phaneritic

• Aphanitic

• Porphyritic

• Glassy