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Rocks PowerPoint Presentation

Rocks

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Rocks

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  1. Rocks • Rocks are defined as a mixture of one or more minerals and organic matter • There are three types of rocks: • Igneous • Sedimentary • Metamorphic

  2. Igneous Rocks • Form when magma cools • Found near volcanic activity • Composition of igneous rocks aredetermined by what minerals they are made from • Texture is determined by how fast the magma cools • Magma that cools quickly forms smooth grained rocks (smooth to touch) • Magma that cools slowly forms course grained rocks (rough to touch)

  3. Igneous Rock Formations • Intrusive Igneous Rocks • Form below the earth surface or inside the Earth • Have a course grained texture because the magma cools slowly • Extrusive Igneous Rocks • Forms on the Earth’s surface • Have a smooth texture because the magma cools quickly

  4. Sedimentary Rocks • Formed from the sediments made during the erosion of other rocks • Sediments settle in low places, usually near or under bodies of water • Over time the sediments form layers that are compacted together and form rocks • Sedimentary Rocks are almost always found in strata or layers

  5. Metamorphic Rock • Form deep in the earth when heat and or pressure change rocks into new and different types of rocks • Contact metamorphism takes when rocks are heated by nearby magma • Heat causes the minerals in the rocks to change • Regional Metamorphism occurs deep in the earth where pressures build up and are able to create a chemical change in rocks