Exam 4: Igneous Rocks and Plutons

Andesite and ____________________ are respectively,____trusive and ____trusive rocks formed in volcanic chains along ____________________ plate boundaries.

When looking at a hand sample of an igneous rock,how would you tell if it is plutonic or volcanic?

Why can an intruding mafic magma assimilate felsic country rock,but an intruding felsic magma cannot assimilate mafic country rock?

The largest intrusive bodies are called ____________________ and by definition,they must have at least ______ square kilometers of surface area.

What are the "scratches" on Devil's Tower,Wyoming?

The Columbia Plateau basalts issued from fissures which are now preserved as ____________________.

Geologists agree that hot-spot volcanism results from a rising mantle plume.

Igneous rocks having a phaneritic texture have ____________________ grains that ____________________ be seen easily by the naked eye.

Any individual volcano always erupts magmas of the same type.

What does a phaneritic texture tell us about the history of an igneous rock?

____________________ is the first ferromagnesian mineral to crystallize from a mafic magma.

Igneous rocks with a texture that is so fine-grained that the crystals are too small to see is ____.

The process of assimilation partly explains why felsic intrusive rocks are much more common than mafic intrusive rocks.

Explain how batholiths and stocks formed via plate tectonics.

List three processes by which felsic and intermediate igneous rocks can be formed from more mafic magmas.

An example of a glassy igneous rock is ____________________.

Give one reason why rhyolite flows are less common than basalt flows.

The process of assimilation ____.

When magma cools slowly,crystal growth proceeds at a relatively ____________________ speed,and the resultant rock is ____________________ in texture.

Rhyolite and granite are extrusive and intrusive rocks formed by volcanism and ____________________,which form at or near plate boundaries as the result of ____________________ and/or ____________________ of plates.