Chapter 5 Igneous Environments

____________is a measure of a material's resistance to flow

Viscosity

A very large pluton that covers more than 100 km2 is called a

batholith

Texture of Granite

coarse grained (phaneritic)

High temperature _____________ viscosity of magma

decreases

When lava solidifies (at or on the surface of the land), the rocks are classified as __________ igneous rocks

extrusive

Composition of Rhyolite

felsic

Texture of Andesite

fine grained (aphanitic)

The gradual increase in temperature with depth in the Earth is known as the

geothermal gradient

Texture of Obsidian

glassy

An example of a coarse grained igneous rock composed mostly of feldspar and quartz is called

granite

Felsic composition _____________ viscosity of magma

increases

Many mineral crystals _________ viscosity of magma

increases

Composition of Diorite

intermediate

Igneous rocks that form when magma solidifies deep beneath the surface of the land are called _________ igneous rocks

intrusive

Composition of Basalt

mafic

When melting forms magma

partial melting produces a magma that is more felsic than the source

An igneous rock with very coarse grained texture in which the minerals are centimeters long is called a

pegmatite

An igneous rock composed of two distinctly different sizes of mineral crystals with a fine-grained matrix around larger crystals is said to have a __________ texture

porphyritic

Which of the following rock types involves dissolved gas in the magma

pumice

Igneous rocks composed of rock fragments of pumice and hot volcanic ash are said to have a _____________ texture

pyroclastic/welded

Composition of Peridotite

ultramafic

Texture of Scoria

vesicular