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Rocks. Environmental Science Earth Science Unit. Questions for Today. What are Rocks? What are the three types of Rock? How are Igneous Rocks Classified? How are Sedimentary Rocks Classified? How are Metamorphic Rocks classified?. Rocks.
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Rocks Environmental Science Earth Science Unit
Questions for Today • What are Rocks? • What are the three types of Rock? • How are Igneous Rocks Classified? • How are Sedimentary Rocks Classified? • How are Metamorphic Rocks classified?
Rocks • Rocks are aggregates of minerals that are held together to form a consolidated mass. • The three general types of Rock are: • Igneous • Sedimentary • Metamorphic
Igneous Rocks • Igneous Rocks are rocks that result from a melt – called magma. • There are two types of Igneous Rocks: • Plutonic Rocks – form beneath the earth’s surface. • Coarse Textured • Ex: Granite and Gabbro • Volcanic Rocks – form above the earth’s surface. • Fine textured • Ex: Rhyolite, Andesite, and Basalt
Sedimentary Rocks • Rocks that form near the surface of the Earth through chemical precipitation from water or by cementation of loose fragments (sediments) • Three types of Sedimentary Rocks: • Clastic – result from cementation of loose fragments. • Chemical - result from direct chemical precipitation from surface water. • How Halite and Calcite is formed. • Biogeochemical – result from the chemical precipitation by living organisms. • Limestone is the most common biogeochemical sedimentary Rock.
Metamorphic Rocks • Rocks that result when any kind of PRE-existing rock is buried deep in the Earth and subjected to HIGH temperature and pressures. • Most metamorphic rocks show a banded texture of the different sheets of silica • Examples: Slate and Schist
The Rock Cycle • Rocks are all interrelated through the processes that form them. • The Rock Cycle are the interactions of physical and chemical processes that change rocks from one type to another. • The Rock Cycle is the slowest of the earth’s cyclical processes.
The Rock Cycle • The earth’s materials are recycled over millions of years by three processes: • Melting • Erosion • Metamorphism • Rocks from any of the three classes can be converted to rocks of the other two classes, or can be recycled within its own class.
Rock Cycle Terms • Sedimentary Processes: • Transportation/Erosion • Deposition • Deposition of eroded material • Lithification • To become rock, usually through cementation • Uplift • Exposure of crustal rock to the atmosphere
Rock Cycle Animation • Interactive Rock Cycle