Exam 3: Igneous Rocks

Pegmatites are smaller volume, intrusive bodies with glassy textures.

The most common non-ferromagnesian silicate minerals (>40 %)in most igneous rocks are ________.

How long does it take for a large magma body at great depth to cool and completely crystallize?

Bowen's reaction series predicts the sizes of the different mineral grains that grow from crystallizing magmas.

Lava rarely if ever has a vesicular texture.

What kind of coarse grained plutonic rock would you expect to find in the ocean crust underneath an undersea basaltic volcano?

What igneous rock is named for a prominent, volcanic mountain range in western South America?

What would you name a light pink, aphanitic, fragmental pyroclastic with sparse quartz phenocrysts?

Glassy igneous rocks form when magma cools too fast for mineral grains to grow.

What would you name an intermediate coloured (35% dark minerals), phaneritic rock with large greenish-black amphibole phenocrysts?

Which process describes how the removal and isolation of early-formed mineral grains can cause the composition of the remaining magma to change?

A ________ is an intrusive, igneous rock body that is tabular and concordant.

In a series of basaltic lava flows on Hawaii, the top and bottom of each flow is difficult to distinguish just by looking at the layers of rock.What are some rock characteristics (texture, mineralogy, etc.)and other features that you might use to recognize individual lava flows?

Visible quartz and potassium feldspar grains are the main constituents in which igneous rock?

What would you name a black, phaneritic rock with 25% Ca-plagioclase and the remainder composed of olivine, pyroxene, and amphibole?

Which igneous rock is the phaneritic equivalent of komatiite?

Examine the words and/or phrases for each question below and determine the relationship among the majority of words/phrases. -Choose the option that does not fit the pattern.

The temperature within the Earth ________ with depth because rocks are poor conductors of heat and they contain small amounts of radioactive elements that generate heat.This gradual change in temperature with depth is called the ________.

While the ultramafic rock, peridotite, comprises the bulk of the mantle, the earth hasn't been hot enough to make much ________ (its volcanic equivalent)since the Precambrian.

The last minerals to crystallize in Bowen's reaction series result in igneous rocks with a ________ composition.