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NASA video. The Rock Cycle. The three types of rocks Igneous sedimentary Metamorphic A ll types of rock are subject to processes that change one rock type into another. Igneous Rocks. Formed from cooled and solidified magma Intrustive
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NASA video The Rock Cycle
The three types of rocks • Igneous • sedimentary • Metamorphic All types of rock are subject to processes that change one rock type into another.
Igneous Rocks Formed from cooled and solidified magma • Intrustive • formed from the cooling of magma within the earth’s crust • Cools and hardens slowly • Coarse grained- forms large, well-developed crystals • Extrusive • melted rock that hardens on the earth’s surface • Lava cools rapidly • fine grained rocks
Composition of Igneous Rocks • Felsic- Rocks in the granite family • Light colored • High silica content • Low magnesium and iron content • Mafic- Rocks in the basalt family • dark colored • lower silica content • high mg and fe content • Andesitic - Medium Silica • Green, grey, or brown
Sedimentary Rocks • rock formed from the debris of both other rocks and living matter. • 90% of the earth’s crust is made from igneous rock, but 75% of the world’s land surface is covered with thin layers of debris or sediments. • These sediments settle on the beds of oceans, lakes, and rivers, and recompacted over millions of years to form sedimentary rock.
How are Sedimentary Rocks Formed? • DIAGENESIS- • the process that turns loose sediments into rock • COMPACTION- • the slow squeezing of sediment to form hard rock • CEMENTATION- • The binding together of compacted sediments by chemicals like calcite, silica, and iron
3 types of Sedimentary Rock: • CLASTIC- form from rock fragments weathered and eroded by glaciers, wind, rivers, and waves. • ORGANIC- rock made from the remains of plants and animals • CHEMICAL- rock made from chemicals dissolved in water
BEDDING PLANE- a boundary between one layer of sedimentary rock and another
Metamorphic Rocks • formed from other rocks as a result of intense heat, pressure, and chemical processes • most form deep beneath the surface of the earth • formed from existing igneous, sedimentary, or metamorphic rock
Types of metamorphic formation: • Contact metamorphism: • when hot magma pushes through existing rock, changing the structure and composition of the rock. Only rocks near the magma are changed. • Regional metamorphism: • movement of one tectonic plate against another causes heat and pressure, affecting rocks over an area of many thousands of kilometers
Types of metamorphic rocks: • Foliated: • show visible parallel bands of minerals ex: slate, schist • Unfoliated: • no bands of crystals ex: quartzite, marble
animation Interactive animation