Transcript Rock Cycle
Rocks Three Types of rock • Igneous • Metamorphic • Sedimentary Three totally different types of rock that all basically come from the same materials Q: So how do we get such different rocks? They all look and act so differently, how do they all form? Igneous Rocks? Sedimentary Rocks? Metamorphic Rocks? A: The Rock Cycle!!! The process of rocks changing from one type of rock to another Igneous Rocks Sedimentary Rocks Main Concept: Any rock type can be changed into any of the other two and back again through the Rock Cycle Metamorphic depending onRocks conditions Igneous The type of igneous rock depends on how fast it cooled! Rocks All Igneous rock comes from molten material Molten material comes from volcanoes How to get Igneous Rocks: Melting of IsMaterial made from exploding material up here Is made from cooled magma down here Can you see the big differences Cooling Magma Explosive Volcanism in these two rocks? Large Crystals Lots of holes Weathering • If rocks are exposed at the surface; they are exposed to the elements in the air. • All the “elements”: rain, wind, animals, plants, ice and even simply a release of pressure can cause the chemical bonds in rocks to break apart. • The process of breaking the bonds in rock and making it “softer” is called: Weathering! Erosion • After a rock has been weathered, it is easy to break. • If a rock breaks into pieces it becomes easier to move from one place to another. • The movement of rock pieces and or soil from one place to another by natural processes is called: Erosion! The cliff is slowly falling down! The pile of sediments here used to be part of this cliff! Sedimentary Rock =cemented sediments This Sandstone in Utah is made from sand that has been cemented together The sand here is loose and not cemented together Can you see the different layers of sand? Sedimentary Rock Recipe 1. Start at the Surface 2. Weather (Break Up) 3. Erode (Carry Away) 4. Sedimentation & Deposition Layers of sand and sediments Rain moves sand, dirt, and rocks down to the ocean 5. Compaction & Cementation Igneous rock © Beadle, 2009 Sediments worn away gather here! How to get Sedimentary Rocks: Weathering Erosion Deposition Cementation Rocks get broken down by exposure to water, wind, etc… Broken down sediments are transported towards the sea and spread out Broken down rocks fall apart Water and pressure helps bond the particles of sediment together to make a rock This is what it looks like in real life: Weathering (Rock broken down by exposure to rain, wind, etc..) Cementation (eventually pieces get stuck together and becomes a rock) Erosion Deposition (smaller pieces are spread out across area) (pieces fall down to bottom of cliff) Rivers can do a lot of this on their own: You can see lots of sediments flowing in the river Deposition is taking place when the river meets the ocean You can see lots of sediments spreading out! Evaporation: New rocks can be formed when water is evaporated When the water leaves, the electrons of the chemicals that make up the rocks are attracted to each other and cause clumps of rock to form from the small particles left behind. Now all that is left are salty rocks that form a dry lake bed There used to be a nice deep ocean here But then the water evaporated… Limestone is very common in the mountains of Utah Q: Where did this limestone originally come from? A: Underwater! Limestone is the remains of sea critters shells that have been compacted together to form rock at the bottom of a sea Pressure and Heat Lead to Metamorphic Rocks • Rocks that get buried again can get squished and heated to the point that they change! This rock is called “Gneiss” (nice). Q: Can you remember what it has “morphed” from? A: Granite!!! If you look closely, you can see the same minerals in both rocks! The rock cycle is an active process that you can see just about everywhere outside: The white tops of these mtn’s are granite= Igneous Erosion is actively breaking down the mountains (forming canyons!) Deposition: minerals from the Granite spreading out as sand! (This makes the soil of the valley) Soil is basically all the small broken up pieces of rocks! Broken down tons of times into smaller and smaller sediments Underneath all the sand, sediment is being compacted =Sedimentary The Real Rock Cycle ***You will need to know the process to make each type of rock! Rock Cycle with illustrations: Let’s connect the rock cycle with plate tectonics! Q: What rock will we get if two continental plates collide? Plate motion Cooler Crust Convection current Plate motion Convection current Hot Mantle Continental plate collides with Continental Plate causing mountains to form! Plate motion Compression = Metamorphic Hot Magma Plate motion Continental collides with Oceanic: Cloud will bringExplosion falling water Volcanic Extrusive Igneous Rock Label where metamorphic, igneous & sedimentary rocks are formed as the numbers appear: 6 6 6 7 5 2 3 plate motion 3 4 1 Divergent Hot Mantle Convergent plate motion Cloud Extrusive Igneous Intrusive Igneous Intrusive Igneous Sedimentary Metamorphic Plate Tectonics Rock Cycle Key: Notice where metamorphic, igneous & sedimentary rocks are processed & formed. Sedimentary Metamorphic Melted rock Assessment: Identify where the terms/description on the left should go in the rock cycle on the right • • Heat, Pressure Extrusive (Volcanic Eruptions) • • • Deposition & Cementation Melting Intrusive (Cooling & Crystallization) • Weathering & Erosion