There are 3 Major Rock There are 3 Major Rock GroupsGroups

There are 3 Major There are 3 Major (Geologic)(Geologic) Rock GroupsRock Groups

Not the Rolling Stones, Kiss, or Van HalenNot the Rolling Stones, Kiss, or Van Halen

1. Igneous Rock1. Igneous Rock

2. Sedimentary Rock2. Sedimentary Rock

3. Metamorphic Rock3. Metamorphic Rock

Rocks are made of Rocks are made of mineralsminerals

and make up Earth’s solid crustand make up Earth’s solid crust

A. A. Igneous RockIgneous Rock--Forms when a hot molten liquidForms when a hot molten liquid below below ground, calledground, called magmamagma,, or above ground, or above ground, called called lavalava, “, “crystallizescrystallizes” --meaning ” --meaning coolscools and solidifies.and solidifies.

(FYI: Most of the continental crust is igneous (FYI: Most of the continental crust is igneous rock.)rock.)

Magma forms 3 ways:Magma forms 3 ways:1.1. Rock is heatedRock is heated2.2. Pressure releasedPressure released3.3. Change compositionChange composition

Basalt lava (glowing rock) oozes over basalt lava flow Holt

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1. 1. Intrusive Igneous RockIntrusive Igneous Rock

-Cools & crystallizes inside -Cools & crystallizes inside EarthEarth

-Slow cooling=large (coarse) -Slow cooling=large (coarse) crystals form crystals form

2. 2. Extrusive Igneous RockExtrusive Igneous Rock

-Forms on surface (exterior) of -Forms on surface (exterior) of EarthEarth

-Fast cooling=small -Fast cooling=small (fine) (fine) or no or no crystals formcrystals form

Texture of Igneous RockTexture of Igneous Rock

--Slow Slow cooling cooling forms large forms large crystals. crystals.

(Coarse-grained (Coarse-grained Texture)Texture)

--FastFast cooling forms cooling forms small crystals. small crystals.

(Fine-grained (Fine-grained Texture)Texture)

Rock ID practiceUse the rock key to identify the various rocks on your table:

Igneous Rocks Classified according to composition & texture

Glassy- shiny and looks like glass, does not have crystals.

Ex: obsidian (volcanic glass)

Fine-grained-made of interlocking crystals. Ex: basalt - the most common extrusive igneous rockCrystals are not that easy to see.

BASALT

More Igneous Rocks…

Course Grained Texture= Granite

More Igneous Rocks…Porous- no crystals, cools rapidly, looks

like a sponge. Gas bubbles formed in the molten liquid and then “froze”.

Ex: pumice

B. Sedimentary RockB. Sedimentary Rock*There are *There are 33 types of sedimentary rocks. types of sedimentary rocks.

*Often times, sand, mud, pebbles, or *Often times, sand, mud, pebbles, or shells settle out in wind and water, get shells settle out in wind and water, get compactedcompacted and/or and/or cementedcemented together, together, and harden into rock.and harden into rock.

Here, rocks hardened in layers called strata from a process known as… stratification.

Three Types of Sedimentary Three Types of Sedimentary RockRock

1. 1. ClasticClastic - -forms when rock or mineral forms when rock or mineral fragments are cemented together.fragments are cemented together.

2. 2. ChemicalChemical forms when minerals forms when minerals crystallize out of a solution, such as sea crystallize out of a solution, such as sea water, to become rock.water, to become rock.

3. 3. OrganicOrganic forms from the remains of once-living forms from the remains of once-living plants and/or animals. (can contain visible plants and/or animals. (can contain visible fossilsfossils))

Ex: LimestoneEx: Limestone CoalCoal

ChalkChalk

C. Metamorphic RockC. Metamorphic Rock

-Rocks that have undergone a change in -Rocks that have undergone a change in texture, structure, or composition.texture, structure, or composition.

-Changes in -Changes in heat and pressure heat and pressure cause cause rocks to change from one form to another.rocks to change from one form to another.

Textures of Metamorphic RockTextures of Metamorphic Rock

Foliated the texture of metamorphic rock in which the mineral grains are arranged in layers or bands of color.

NonfoliatedNonfoliated

-The texture of -The texture of metamorphic rock metamorphic rock in which the in which the mineral grains are mineral grains are notnot arranged in arranged in layers or bands of layers or bands of colors.colors.

Rocks are made, Rocks are made, destroyed, and created destroyed, and created again, from again, from processesprocesses along the along the Rock CycleRock Cycle..

Rock Cycle QuizRock Cycle Quiz What process forms What process forms

magma from solid rock?magma from solid rock? What process forms a What process forms a

rock from lava?rock from lava? What processes form What processes form

sediment from solid rock?sediment from solid rock? What processes form a What processes form a

Sedimentary Rock from Sedimentary Rock from sediment?sediment?

What is the resulting rock type What is the resulting rock type when an igneous rock changes when an igneous rock changes because of added heat & because of added heat & pressure?pressure?

What is the resulting rock What is the resulting rock type when magma cools & type when magma cools & crystalizes?crystalizes?

MeltingMelting

CoolingCooling

Weathering & Weathering & ErosionErosion

Compaction & Compaction & CementationCementation

MetamorphicMetamorphic

IgneousIgneous