The Rock CycleThe Rock Cycle

Igneous rocksIgneous rocks

• Formed by the cooling and Formed by the cooling and crystallization of magma (magma is crystallization of magma (magma is molten rock inside the earth)molten rock inside the earth)

• Intrusive igneous rocks are Intrusive igneous rocks are crystallized deep in the Earthcrystallized deep in the Earth

• Extrusive igneous rocks are formed Extrusive igneous rocks are formed where the lava flows to the surfacewhere the lava flows to the surface

• Igneous rocks are Igneous rocks are classified based onclassified based on– TextureTexture– ShapeShape– SizeSize– Arrangement of Arrangement of

mineralsminerals

Metamorphic RocksMetamorphic Rocks

• Can be formed in different waysCan be formed in different ways• Generally, they are re-crystallized by heat Generally, they are re-crystallized by heat

and pressureand pressure• Igneous, sedimentary and metamorphic Igneous, sedimentary and metamorphic

rocks can become new metamorphic rocksrocks can become new metamorphic rocks• The new rock may have some of the The new rock may have some of the

original characteristics of the old rocksoriginal characteristics of the old rocks• Sometimes the change is so complete that Sometimes the change is so complete that

new minerals are formed and texture is new minerals are formed and texture is changedchanged

• Two types of Two types of Metamorphic Metamorphic RocksRocks

FollatedFollated- rock has - rock has layerslayers

Non-FollatedNon-Follated- is - is crystalline and crystalline and shows no layersshows no layers

Sedimentary RocksSedimentary Rocks

Formed at or near the surface of the EarthFormed at or near the surface of the Earth

Sediments are deposited in beds or layers Sediments are deposited in beds or layers by water or wind as a result of erosionby water or wind as a result of erosion

Ninety-eight percent of sedimentary rocks Ninety-eight percent of sedimentary rocks are shale, sandstone and limestoneare shale, sandstone and limestone

Types of Sedimentary Types of Sedimentary RockRock

ClasticClastic-rock fragments or -rock fragments or

minerals broken minerals broken from pre-existing from pre-existing rockrock

ChemicalChemical-results from chemical -results from chemical

precipitation from precipitation from fresh or salt waterfresh or salt water

OrganicOrganic-made from plant or -made from plant or

animal particlesanimal particles

The Rock Cycle