ROCKSROCKS

What is a rock?What is a rock?

What is a rock?What is a rock? Made of entirely one mineral or several Made of entirely one mineral or several

minerals. minerals.

Could contain organic matter (composed Could contain organic matter (composed of living material, usually carbon based).of living material, usually carbon based).

The chemical make-up of the rock may The chemical make-up of the rock may vary from one sample to another. vary from one sample to another.

Types of RocksTypes of Rocks What are theWhat are the three three classes of rocks?classes of rocks?

Types of RocksTypes of RocksWhat are theWhat are the three three classes of rocks?classes of rocks?1. Igneous Rocks1. Igneous Rocks

2. Sedimentary Rocks2. Sedimentary Rocks

3. Metamorphic Rocks3. Metamorphic Rocks

Igneous RocksIgneous Rocks Name comes from the Latin word “ignis” Name comes from the Latin word “ignis”

meaning from fire.meaning from fire. Formed when super hot magma or lava cools. Formed when super hot magma or lava cools. There are seven different classes based on There are seven different classes based on

chemical composition of the igneous rock. chemical composition of the igneous rock.

Types of Igneous RocksTypes of Igneous RocksExExtrusive Igneous trusive Igneous

Rocks:Rocks:

Formed from lava Formed from lava that that quicklyquickly solidifies at the solidifies at the cooler surface. cooler surface.

Produces fine-Produces fine-grained rocks.grained rocks.

Ex. basalt and rhyoliteEx. basalt and rhyolite

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Types of Igneous RocksTypes of Igneous RocksIInnttrusive Igneous Rocks:rusive Igneous Rocks: Trapped magma under Trapped magma under

the crust solidifies slowly.the crust solidifies slowly. Intrusive rocks are Intrusive rocks are

composed of larger composed of larger crystals because form crystals because form slower. slower.

Larger crystals give these Larger crystals give these rocks a rougher texturerocks a rougher texture

Ex. graniteEx. granite

Mount Rushmore is Mount Rushmore is carved from granite in carved from granite in the Black Hills of the Black Hills of South Dakota. South Dakota.

Mount Rushmore is carved from granite in the Black Hills of South Dakota.

Igneous RockIgneous Rock

The most common The most common known igneous rock known igneous rock is granite. is granite.

It is composed It is composed almost entirely of almost entirely of feldspar and quartzfeldspar and quartz

Igneous Rocks: Mafic vs. Igneous Rocks: Mafic vs. FelsicFelsic Mafic : Mafic : chemically chemically

composed of iron composed of iron and magnesium, and magnesium, and smaller and smaller amounts of quartz.amounts of quartz.

Felsic: chemically Felsic: chemically composed of composed of potassium, potassium, feldspar, and large feldspar, and large amounts of quartz.amounts of quartz.

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Bell Ringer: Rocks What is the difference between intrusive

and extrusive igneous rocks?

T or F: Intrusive igneous rocks are composed of larger crystals then extrusive igneous rocks.

Would mafic or felsic magma be magnetic? Explain your answer.

Igneous Rock Igneous Rock FormationsFormations

Extrusive Igneous StructuesExtrusive Igneous Structues:: volcanoesvolcanoes

Intrusive Igenous Intrusive Igenous Structures:Structures:

batholithsbatholiths laccolithslaccoliths sills sills dikesdikes

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Sedimentary RocksSedimentary Rocks All sedimentary rocks are made of materials All sedimentary rocks are made of materials

called sediments deposited by natural and called sediments deposited by natural and chemical processes.chemical processes.

Sediments become Sediments become cementedcemented or or compactedcompacted together over time forming a solid rock together over time forming a solid rock

Uluru (Ayers Rock) in Australia, the world's largest monolith, is made of sandstone.

Types of SedimentsTypes of Sediments Tiny grains of sandTiny grains of sand Broken pieces of rock along the Broken pieces of rock along the

bottom of a streambottom of a stream Fragments of seashellsFragments of seashells Layers of mudLayers of mud Organic matter (plant and animal Organic matter (plant and animal

remains)remains)

Sediments and Sediments and Sedimentary RocksSedimentary Rocks Gravity, water, or wind carries them to a destination.Gravity, water, or wind carries them to a destination.

Sediments deposit in layers over time. (strata= layers)Sediments deposit in layers over time. (strata= layers) Loosely deposited sediments eventually form a solid rock Loosely deposited sediments eventually form a solid rock

by:by:1.Compaction: 1.Compaction: sediments squeezed together by sediments squeezed together by

gravity/pressure.gravity/pressure.2. Cementation2. Cementation: sediments glued together by minerals : sediments glued together by minerals

deposited by water. deposited by water.

Sedimentary RockSedimentary Rock The most common The most common

sedimentary rock is sedimentary rock is limestone.limestone.

Develops from living Develops from living remains (shells, remains (shells, mollusks)mollusks)

CoalCoal is another is another example of a example of a sedimentary rock sedimentary rock derived from organic derived from organic remains.remains.

Sedimentary RockSedimentary Rock

Often preserve some characteristics from Often preserve some characteristics from which they were formed. which they were formed.

Ripple marks formed in the sand will appear Ripple marks formed in the sand will appear in the rock formed from the sand deposits.in the rock formed from the sand deposits.

Ripple marks formed in thesand by wind

Sedimentary RocksSedimentary Rocks The source of most fossil The source of most fossil

remains.remains.

The age of a rock can be The age of a rock can be determined by studying determined by studying the fossils within it.the fossils within it.(Radiometric Dating)(Radiometric Dating)

Identify when prehistoric Identify when prehistoric organisms and vegetation organisms and vegetation thrived and became thrived and became extinct. extinct.

Fossilized Leaves

Sedimentary RocksSedimentary Rocks The diverse colors The diverse colors

within the sedimentary within the sedimentary layers (strata) gives layers (strata) gives scientists an idea of scientists an idea of their chemical make-their chemical make-up. up.

The red and pink bands The red and pink bands in the Grand Canyon in the Grand Canyon exhibit the iron found exhibit the iron found in the sediment.in the sediment.

Sedimentary Rocks: Sedimentary Rocks: LocationLocation

Sedimentary rocks cover Sedimentary rocks cover almost all of the ocean floor almost all of the ocean floor and about three-fourths of and about three-fourths of Earth's surface land area. Earth's surface land area.

Metamorphic RockMetamorphic Rock Metamorphism: change in the chemical Metamorphism: change in the chemical

make-up of rocksmake-up of rocks Heat, pressure, and hot fluids cause rocks to Heat, pressure, and hot fluids cause rocks to

change into other rocks. change into other rocks. Where would this most likely occur?Where would this most likely occur?

Metamorphic RockMetamorphic Rock Heat, pressure, and hot fluids cause rocks Heat, pressure, and hot fluids cause rocks

to change into other rocks. to change into other rocks. Where would this most likely occur? Where would this most likely occur?

within the Earthwithin the Earth- at subduction zonesat subduction zones

Metamorphic RockMetamorphic Rock

The geologic processes that created the North Cascades changed the original rock into metamorphic rock.

Formed from compression of Tectonic plates

Types of Metamorphic Types of Metamorphic RockRock

SlateSlate is a common is a common form that is easily form that is easily split into slabssplit into slabs

GneissGneiss (pronounced (pronounced “nice”) contains “nice”) contains light and dark bandslight and dark bands

GraniteGranite is also a is also a common typecommon type

The Rock CycleThe Rock Cycle Almost all of the rocks that compose Almost all of the rocks that compose

the Earth’s crust today are made of the Earth’s crust today are made of the same stuff as the rocks that the same stuff as the rocks that dinosaurs and other ancient life forms dinosaurs and other ancient life forms walked, crawled, or swam over. While walked, crawled, or swam over. While the stuff(matter) that rocks are made the stuff(matter) that rocks are made of has changed, the rocks themselves, of has changed, the rocks themselves, have not. have not. Over time rocks are Over time rocks are recycled into other rocks. recycled into other rocks.

The Rock CycleThe Rock Cycle

The Rock CycleThe Rock Cycle