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Rock Cycle- Sec. 2.1. Vocabulary to know:. Extrusive igneous Intrusive igneous Lava Weathering Erosion Sediment Deposition Compaction Cementation Sedimentary rock Heat Pressure Metamorphism Metamorphic rock Melting Magma Cooling Hardening Crystallization. The Rock Cycle.
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Rock Cycle- Sec. 2.1 • Vocabulary to know: • Extrusive igneous • Intrusive igneous • Lava • Weathering • Erosion • Sediment • Deposition • Compaction • Cementation • Sedimentary rock • Heat • Pressure • Metamorphism • Metamorphic rock • Melting • Magma • Cooling • Hardening • Crystallization
Vocabulary to know: Igneous rock Magma Lava Extrusive igneous rock Intrusive igneous rock Texture Composition Silicate Section 2.2
What are igneous rocks? • Igneous rock- • Form from molten rock deep within the Earth that has cooled… OR… • From molten rock that has reached the surface and cooled lava • Temperatures deep within the Earth are hot enough (14000F to 23000F) to melt rock
Where do igneous rocks come from? • Volcanoes! • Extrusive igneous rock- • Forms when lava cools on Earth’s surface • Intrusive igneous rock- • Forms when magma cools within the Earth
Textures of igneous rocks • Texture = size of the rock’s mineral crystals • Largecrystals-slow cooling time • Intrusive rocks commonly have large crystals • Small/No crystals- fast cooling time • Extrusive rocks commonly have small or no crystals
Answer = look at their composition! • Igneous rocks are mainly made up of silicate minerals
Ship Rock • Formed 1km below Earth’s surface • It was once intrusive igneous rock • It is what’s left behind of magma that once fed a volcano • Through weathering and erosion, surface rock has been worn away… • …Ship Rock survives because igneous rock is usually harder than other types of rocks
Vocabulary to know: Sedimentary rock Sediment Cementation Coal Limestone Crossbeds Ripples Section 2.3
What are sedimentary rocks? • Sedimentary rock- • Forms from loose material (sediments) that get pressed together (cemented) into rock • Sediments- • Can be pieces of rocks, minerals, plants, or animals
Sedimentary rock formation… • Rainwater washes away rock particles… • Flow downhill to streams and rivers… • Eventually these sediments reach the ocean… • Settle on the bottom of the ocean… • Pressure eventually forces these sediments together… • Sedimentary rock is formed!
Fossils can also make sedimentary rock • Coal- • Made up of remains of plants (dead wood, bark, leaves, etc.) • Started forming millions of years ago • Limestone- • Made up of remains of ocean organisms (shells, bones, etc.) • Pressure “squishes” these materials together into rock
Coal formation • A- Dead pieces of plant matter collecting on lake bottom • B- sediments applying pressure on top of plant matter • C- Even greater pressure applied • D- Coal is created
Limestone towers (Mono Lake) • Minerals can dissolve in water … • …and then re-form as the water evaporates • Often they form underwater… • …and as the water level drops they become visible
Sedimentary rocks can teach us about the past… • Crossbeds- • These layers were once moving sand dunes • Ripples- • The surface of this sandstone preserves ancient sand ripples
Vocabulary to know: Metamorphic rock Metamorphism Recrystallization Foliation Foliated rock Nonfoliated rock Section 2.4
What are metamorphic rocks? • Metamorphic rock- • Forms when heat or pressure cause older rocks to change into new types of rocks • Metamorphism- • The process in which existing rock is changed by heat or pressure
Metamorphic rock formation • During metamorphism rocks undergo many changes • Heat and pressure can break the bonds that join the atoms in minerals… the atoms then join together differently • Recrystallization • Rocks do not melt during this process!!!
Foliation • Foliation- • An arrangement of minerals in flat or wavy parallel bands • Foliated rocks- • Develop under pressure • Minerals flatten out or line up in bands • Nonfoliated rocks- • Develop if rock is made up of only one type of mineral • May not be under enough pressure