Geology lesson 7 Igneous rocks

Magma

________ is molten rock beneath the earths surface- underground melt.

Water vapor

________ (h2o) is the most abundant volcanic gas.

Peridotite

________ is an intrusive ultramafic igneous rock found in the mantle.

geothermal gradient

The ________ is when temperatures in the upper crust increase about 25 degrees C per km.

Obsidian

________ is an extrusive igneous rock- no crystals.

Lava

________ is molten rock that has flowed out onto the earths surface.

Earths crust

________ and mantle are primarily composed of solid rock.

Granite

________ is an intrusive igneous rock.

Decompression

________- melting due to a decrease in pressure.

melt forms

A(n) ________ when solid materials become hot and transform into liquid.

Addition of heat induces

________ melting if temperature exceeds melting temperature.

Molten rock

________ is a type of melt.

Igneous rocks

________ are made by the freezing or crystallization of a melt.

Basaltic magma

________ heats the crust.

Gases volatiles

________ give magmas their explosive character.

Lesser amounts of magma

________ is produced at subduction zones (convergent plate boundaries involving the subduction of oceanic crust)

Igneous rocks

________ can either form below the surface or on the surface.

Magma

________ is generated in the uppermost mantle.

Igneous rocks

________ form through the cooling and solidification of magma or lava.

magma is molten rock beneath the earths surface

underground melt

obsidian

sharpest thing on the planet

obsidian is an extrusive igneous rock

no crystals

decompression melting

rapid decrease in pressure can cause the mantle to melt, even without an increase temperature (mid ocean ridges, continental rifts, mantle plumes/hot spots

addition of volatiles

volatiles are chemical compounds that lower the melting temperature of the rock (subduction zones)

addition of heat

induces melting if temperature exceeds melting temperature (mantle plumes/hot spots

decompression melting

if the pressure affecting hot mantle rock decreases while the temperature remains unchanged, magma forms

Decompression

melting due to a decrease in pressure

Three environments where decompression melting occurs

mantle plume/hot spot, continental rift, mid-ocean ridge