Exam 8: Volcanoes and Plutons

Mount Vesuvius is an example of a ____ volcano that is a steep-sided volcano formed by an alternating series of lava flows and pyroclastic deposits and marked by repeated eruption.

If a volcano has a gas-charged eruption, what type of feature would form if the magma chamber collapses into the space that the magma had filled? __________________

Welded tuff and ash-flow tuff deposits derive from what specific type of eruption?

If you saw an ash-flow tuff or a caldera in the field, what type of eruption would have likely caused both to form?

Explain why granite magma is more viscous than basaltic magma.

Explain how fissure eruptions can create flood basalts.

If you find a piece of lava that solidified before the gas had escapes, the bubbles are preserved as holes in this rock are called ____________________.

Swarms of ____________________ are one of the short-term indicators that a volcanic eruption is about to occur.

Magma forms abundantly at transform boundaries because one plate is subducting into the mantle allowing for the formation of magma chambers.

Yellowstone Park is an example of three overlapping ____.

Explain how tectonic accretion led to the formation of the earliest continental crust.

Granitic magma has a lower melting temperature compared to basaltic magma because it contains a higher percentage of which specific mineral? __________________

Explain how temperature is an important indicator of the chemistry of magma.

If you saw a plutonic igneous feature cuts across rocks in the field, what specific feature would this be?

A geologist would expect to find what type of magma composition at spreading ridges because it has a lower density?   _________________

Magma in the asthenosphere is primarily granite in composition because the magma is high in silica in the athenosphere.

Magma with a high-water content has a greater tendency to _________ in the crust as compared with magma with a lower water content.

A composite cone ____.

Geologists hypothesize that Earth's first crust was composed of ____________________ because it is very low in silica and formed when the Earth's interior was much _______ than it is today.

Explain how igneous rocks of intermediate composition are formed from basaltic magma.