Geology Quiz: Part 5

Which THREE factors decrease the melting temperature of a rock?

• Increase in water content

• Increase in pressure

• Increase in mineral content

• Increase in temperature

Why do rocks typically undergo partial melting (at constant temperature and pressure)?

• Due to increase in pressure

• Due to decrease in water content

• Due to increase in temperature

• Due to decrease in mineral content

How can we initiate the melting of a rock buried in the Earth’s crust?

• Increase in temperature

• Increase in water content

• Increase in mineral content

• Increase in pressure

Where do basalt rocks melt more easily and why?

• At the Earth's mantle due to high temperature

• At the Earth's crust due to low temperature

• At the Earth's core due to high pressure

• At the Earth's surface due to low pressure

What do we mean by ‘magmatic differentiation’?

• The process of rocks turning into magma

• The process of magma solidifying into rocks

• The process of magma cooling into rocks

• The process of magma composition changing over time

What are the approximate temperature of crystallization of silicate minerals out of a magma?

• 100-200°C

• 500-700°C

• 800-1000°C

• 1100-1200°C

What type of magmas/rocks would be formed by progressive magmatic differentiation of a starting basaltic magma?

• Granitic

• Andesitic

• Basaltic

• Rhyolitic

Besides magmatic differentiation, what is an alternative model for the genesis of andesitic magmas?

• Partial melting of a mixture of sedimentary, igneous, and metamorphic continental crustal rocks

• Partial melting of a mixture of sedimentary rocks and basaltic oceanic rocks

• Partial melting of rocks in the upper mantle

• Magma mixing

Besides magmatic differentiation, what is an alternative model for the genesis of granitic/rhyolitic magmas?

• Partial melting of a mixture of sedimentary, igneous, and metamorphic continental crustal rocks

• Partial melting of a mixture of sedimentary rocks and basaltic oceanic rocks

• Magma mixing

• Partial melting of rocks in the upper mantle

What is a sill?

• A type of intrusive igneous rock

• A type of extrusive igneous rock

• A type of metamorphic rock

• A type of sedimentary rock