“Learning Target”……..

n  Objective: u  I can describe the rock cycle.

Rocks and the Rock Cycle…Remember rocks go through a “cycle”, meaning they are always changing. New rocks continually form from old rocks and old rocks get recycled. We call this process process the “Rock Cycle”. This process is similar to other cycles we know of such as the water cycle, carbon cycle, and nitrogen cycle.

The Value of Rock •  Rock has been an important natural resource for as long as humans have existed.

•  Ancient and modern civilizations have used granite, limestone, marble sandstone, slate and other rocks as construction materials.

•  Rock is also an important ingredient in concrete and plaster, both of which are commonly used in construction.

Processes That Shape the Earth

•  Certain geological processes make and destroy rock.

•  These processes shape the features of our planet.

•  These processes also influence the type of rock that is found in certain areas.

Processes That Shape the Earth include:

•  • Weathering

• Erosion • Deposition

• Lithification • .

Weathering, Erosion, and Deposition • The process in which water, wind, ice, and heat break down rock is called weathering.

•  Weathering is important because it breaks down rock into fragments from which sedimentary rock is made. •  Wind, water, ice, and gravity then transports soil and sediment from one location to another through a process called erosion. •  As the process continues sediments are later moved by erosion and eventually dropped and comes to rest in a process called deposition.

Processes That Shape the Earth, continued As rock particles and organic matter are moved to a place of deposition and are covered by additional particles, eventually the weight from above will start a process called lithification. Lithification involves two steps: A) compaction --squeezes out the fluids and space that exist between the particles. B) cementation--- results when the fluids that are squeezed out are replaced with minerals that were in the fluids. **Once cementation occurs, the new sedimentary rock has been formed

From Sedimentary Rock to Metamorphic

Temperature and pressure are important:

• If the heat and pressure are high enough, the rock can change into metamorphic rock.

•  If the rock gets hot enough to melt, this creates the magma that eventually cools to form igneous rock.

How the Cycle continues: •  Rock that is buried beneath the earth’s crust is eventually pushed up (uplifted) to the surface thanks to movements within the Earth . This process is called “uplifting”.

• As Erosion continues to chip away at the Earth’s surface , the rock that has been uplifted will eventually be exposed to the Earth’s surface. When uplifted rock reaches the Earth’s surface, weathering, erosion, and deposition begin to help the cycle begin all over again.

What happens to older rock?????

• As new rock is pushed up towards the surface, older rock is pushed down!!.

The Rock Cycle in Action:

Let’s review: Illustration of the Rock Cycle

Rock formation does not have to go through a direct pattern. • Understand that sedimentary rock can become igneous rock just as metamorphic rock can become sedimentary rock!!

• Remember: • The rock cycle is not an overnight process. It may take millions to tens of millions of years for each process in the rock cycle to occur!!!.