| Rocks and the Rock Cycle 1. Rocks are natural solid materials made of one or more minerals. 2. Earth scientists classify rocks into one of THREE main types depending on HOW THE ROCKS FORMED. A. IGNEOUS ROCKS - romed from the cooling and hardening of melted, or molten rock. B. SEDIMENTARY ROCKS - form from SEDIMENTS - small bits of soil, older rocks, shells, and remains of dead plants and animals. C. METAMORPHIC ROCKS - form from heat, pressure, and chemical reactions to existing rocks. The Rock Cycle 1. Weathering, Erosion, compactions, cemenatation, melting, and cooling all interact to FORM AND CHANGE rocks. 2. Metamorphic Rock forms when heat and pressure, or both are applied to either Sedimentary or Igneous Rock. 3. Sedimentary Rock forms when Metamorphic or Igneous Rock is weathered (Physical or Chemical) and Eroded into Sediments and then Compacted and/or cemented. 4. Igneous Rock forms when Magma (below the surface) or Lava ( above the surface) cools. 5. When a rock changes into another type of rock, its minerals can flatten, grow, dissolve, melt, or combine with other minerals. IGNEOUS ROCK "FIRE ROCK" 1. As lava or magma COOLS, it becomes solid, many crystals of varous minerals form from the cooling of lava or magma. 2. The crystals grow together and form one solid igneous rock. 3. An igneous rock is rock that formed as molten material cooled. 4. There are two types of igenous rocks: A. INTRUSIVE IGENOUS ROCKS - when igenous rocks are formed by MAGMA that cooles BENEATH Earth's surface. B. EXTRUSIVE IGNEOUS ROCKS - when igenous rocks are formed by LAVA that cools ON Earth's SURFACE. SEDIMENTARY ROCKS 1. Most of the rocks exposed at the Earth's surface are Sedimentary rocks (75%) 2. Sedimentary rocks are a result of EROSION and WEATHERING. 3. Weathering breaks rocks or remains of plants and animals into smaller pieces called SEDIMENTS. 4. These Sediments are transported to new locations by the agents or Erosion - water, wind, ice, and gravity. 5. Under certain conditions, deposited Sediments recombine to form Solid rock called Sedimentary rock. 6. Sedimentary Rocks are formed from PREASURE of layer after layer of sediments, This process is called COMPACTION. 7. Pressure alone cannot make large sediments like sand stick together, dissolved minerals in liquids acts as a cementing agent in a process called CEMENTATION. 8.CONGLOMERATE is a sedimentary rock formed from SAND and PEBBLES cemented together. 9. Sedimentary rock can be composed of any type of weathered and eroded rock material and sometimes even particles from plants and animals. 10. There are THREE Classifications of Sedimentary Rocks: A. DETRITIAL SEDIMENTARY ROCK - Sedimentary rocks made of broken fragments of ther rocks. They may also contain small amounts of plant and animal remains. These rocks are compacted and cemented together. B. CHEMICAL SEDIMENTARY ROCK - Sedimentary rocks made from the ions and solts taken into solution in the weathering process. Dissolved materials are transported to lakes and oceans where they become concentrated, and they accumulate as solid minerals. C. ORGANIC SEDIMENTARY ROCKS - Sedimentary rocks that have large amounts of the remains on once-living things, also known as fossils. |
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