The Rock Cycle The Rock Cycle the process

The Rock Cycle

The Rock Cycle: the process that makes new rock from old rock material; changes rock from one type to another • A rock is a naturally occurring mixture of crystals of one or more minerals. • Processes that drive the rock cycle: – Weathering, erosion, & deposition – Heat & pressure: increased temp. & squeezing

Processes that drive the Rock Cycle • Processes that drive the rock cycle: – Weathering, erosion, & deposition • Weathering: Breaking down of rock by wind, rain, ice, water, & heat • Erosion: transport of rock • Deposition: dropping off rock, soil, dead animals – Heat & pressure: increased temp. & squeezing

Weathering: Breaking down of rock by wind, rain, ice, water, & heat (see an example of ice in action below)

Weathering

Erosion

Erosion & Deposition

Weathering, erosion, & finally deposition

The Rock Cycle

Weathering & erosion Interactive rock cycle

Three types of rocks: • Sedimentary: – formed from deposits by compaction & cementation; can be formed by any type of rock exposed at the surface of the Earth – Example: limestone

Sedimentary Rock • After any type of rock is exposed on top of the Earth & undergoes weathering, the materials are eroded & deposited. • This forms sed. rock through cementation and compaction of soil, rock, dead animals, etc. (lithification) • Remains of plants and animals become trapped in the layers and over long periods of time become fossils. • Thus, sed. rock is nicknamed fossil rock.

Compaction and Cementation • Over time these 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.

Igneous Rock • Igneous: rocks formed from the cooling of magma – Two types: extrusive (think exit) & intrusive (think inside) – Example: pumice

Igneous Rock: Greek word for fire • form from hot molten rock (magma) • Melting occurs deep in the Earth near active plate boundaries or hot spots, then rises toward the surface. • Two groups: – intrusive or extrusive, depending upon where the molten rock solidifies

Extrusive Igneous Rock • Produced when magma exits and cools outside of or very near the Earth's surface • 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 the type of rock that forms Pumicecooled quickly Obsidian-cooled slowly

Black Sand Beach: Hawaii

Intrusive Igneous Rock • Intrusive, or plutonic, igneous rock forms when magma is 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

Metamorphic Rock • Metamorphic: sedimentary rock that gets changed by heat & pressure as earth’s crust is recycled – Examples: slate & marble

Metamorphic Rock: rocks that have changed/morphed • Once igneous or sedimentary rocks • How do sedimentary and igneous rocks change? – When large pieces of crust collide, rock is forced downward. • Heat and pressure squeeze the sedimentary or igneous rock and change it into metamorphic rock.

Metamorphic Rocks Shale, a sedimentary rock, is changed by heat and pressure into slate shale slate Limestone, a sedimentary rock, is changed by heat and pressure into marble. Marble is used to make statues and countertops. Limestone Marble

Rock Cycle Song (Sing to the tune of "Row, Row Your Boat") • SEDIMENTARY rock Has been formed in layers Often found near water sources With fossils from decayers • Then there's IGNEOUS rock Here since Earth was born Molten Lava, cooled and hardened That's how it is formed • These two types of rocks Can also be transformed With pressure, heat and chemicals METAMORPHIC they'll become.