The Rock Cycle Chapter 4 Pages 90-111
What is the Rock Cycle? Process in which: • A rock forms • A rock changes from one type to another • A rock forms again by processes on and in the Earth.
Three Types of Rock • The three types of rock are: • Sedimentary • Igneous • Metamorphic
Sedimentary Rock Formed by: • Weathering and Erosion of rocks into smaller pieces or sediment. • Deposition • Compaction and Cementation • Any rock (igneous, sedimentary, or metamorphic) exposed at the Earth's surface can become a sedimentary rock
Weathering: BREAKDOWN of rock by water, constant heating and cooling or other natural causes, to form sediment. Erosion: MOVEMENT of sediment by wind and water Weathering and Erosion
Deposition • Streams and rivers transport sediment to lakes or oceans, or deposit it on nearby floodplains where it accumulates
Compaction and Cementation • Over time these deposited grains and pieces of rock are compacted and cemented together in layers. • The compaction and cementation occurs when sediment is squeezed by the weight of the sediment layers above it. • Each layer may be different from the next layer depending on the type of sediment that is deposited. • Fossils are often found in sedimentary rock.
Sedimentary Rocks Breccia Shale Sandstone
Sedimentary Rock • The remains of plants and animals become trapped in the layers and over long periods of time and become fossils. .
Igneous Rock • Igneous rocks (from the Greek word for fire) form from hot molten rock (magma). • The melt originates deep within the Earth near active plate boundaries or hot spots, then rises toward the surface. • Igneous rocks are divided into two groups, intrusive or extrusive, depending upon where the molten rock solidifies. • Where do you think INtrusive igneous rock forms? Where do you think EXtrusive igneous rock forms?
Extrusive Igneous Rock • Extrusive igneous rock is produced when magma exits and cools outside of, or very near the Earth's surface. • These are the rocks that form at erupting volcanoes • The magma cools and solidifies almost instantly when it is exposed to the cool temperature of the atmosphere. • Cooling time determines rock fromed. . • Obsidian-cooled slowly • Pumice-cooled quickly
One of nature's rarest wonders stretches across the island of Hawaii's shores — the black-sand beach of Punalu'u. This magnificent beach formed when lava from two of the world's most active volcanoes, Mauna Loa and Kilauea, spilled into the ocean and quickly cooled, breaking into minuscule pieces that now comprise the "sand." Black Sand Beach: Hawaii
Intrusive Igneous Rock • Intrusive, or plutonic igneous rock forms when magmais trapped deep inside the Earth. • Great globs of molten rock rise toward the surface. Some of the magma may feed volcanoes on the Earth's surface, but most remains trapped below, where it cools very slowly over many thousands or millions of years until it solidifies. • Intrusive igneous rock can be pushed to the surface by plate movement. • Granite is a type of intrusive igneous rock.
Metamorphic Rock • Metamorphic rocks are rocks that have "morphed“, or changed into another kind of rock. • These rocks were once igneous or sedimentary rocks. • How do sedimentary and igneous rocks change? • When large pieces of crust collide (convergent boundary, subduction zone), rock is forced downward. • Heat and pressure squeeze the sedimentary or igneous rock and change it into metamorphic rock.
Metamorphic Rock • Limestone, a sedimentary rock, is changed by heat and pressure into marble. Marble is used to make statues and countertops. • Shale, a sedimentary rock, is changed by heat and pressure into slate S: Limestone S: shale M: slate M: Marble
The Rock Cycle THE ROCK CYCLE
Review • Name the 3 types of rock. • This process causes rock to break down into smaller pieces called sediment.____________________________ • This action carries sediments to rivers and lakes._______________ • Sedimentary rock is formed by _________________and ______________. • Igneous rock is formed from_______________________________. • Two types of igneous rock______________ and ______________. • What causes sedimentary and igneous rock to become metamorphic rock? __________and___________ • Intrusive igneous rock forms_________________________ • Extrusive igneous rock forms_____________________________ • Can any rock become a sedimentary rock?__________________ • Which type of rock would contain fossils?_____________________