Exam 3: Igneous Rocks

A ________ is an open cavity in a volcanic rock that was filled by a gas bubble when the lava was still mainly liquid.

A porphyritic texture includes two different sizes of mineral grains, the phenocrysts and the vesicles.

Aphanitic means that individual crystals are so small they are "not visible" to the naked eye.

Felsic rocks have silica contents of ________ are rich in ________.

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.

At about 100 km depth across most of the upper mantle, peridotite is about ________, which is very close to its melting temperature.

Igneous comes from the Greek word for fire.

In an igneous rock with phaneritic texture, the mineral grains are visible to the unaided eye.

A sill has an exposed surface area of at least 100 square kilometres.

When magma cools and consolidates without growth of mineral grains, it is

The aphanitic equivalent of peridotite is

Plutonic rocks are emplaced at depth yet they can be seen at the Earth's surface due mainly to ________.

What igneous rock is the aphanitic chemical equivalent of diorite?

Igneous rocks are classified on the basis of what two main characteristics?

A ________ is the largest, discordant body of intrusive, igneous rock.

The mechanism of selectively removing the minerals which melt at the lowest temperature is ________.

Most lavas crystallize to form igneous rocks with phaneritic textures.

What name would you assign to a dense phaneritic green rock having olivine and pyroxene as dominant minerals?

Mafic rocks like basalt and gabbro ________.

Magmas are formed by partial melting in the upper 250 km of the mantle and crust.