2. Rock Cycle
ROCK CYCLE
Sections on this page
1- Rock Cycle Notes- Scroll down and use the information to complete your notes
2- Rock Cycle Clips
How the Earth's Crust is formed and reformed….
1. MAGMA/LAVA
Start with molten rock, known as magma deep in the mantle. It rises to the crust and
some of it cools and hardens (crystallizes) within the crust and some of it exits onto the
crust surface. Magma can exit the crust at fault lines and also through volcanic eruptions.
We call it lava once it exits the crust.
Magma/lava can only create types of Igneous Rocks initially.
2. IGNEOUS ROCKS (Intrusive and Extrusive)
Magma that exists the mantle cools and hardens (crystalizes) into IGNEOUS rock.
Intrusive Igneous rock is formed when magma cools and hardens within cracks in the
crust before it can escape to the surface. Intrusive igneous rocks crystallize (solidify)
below the Earth's surface. The slow cooling that occurs there allows rocks with large
crystals to form. “Veins” of metallic minerals like gold and silver are created this way.
Granite and quartz are intrusive igneous rocks.
Extrusive Igneous rocks occur when lava erupts onto the surface (volcano, ridge) where
they cool quickly to form igneous rocks with small crystals.
Basalt, obsidian, and pumice, are extrusive igneous rocks.
3. SEDIMENTARY ROCK
When rock is weathered (broken up), and eroded (collected and moved/swept away),
and deposited (placed/piled) somewhere else, it creates layers of sediment (dirt/mud)
composed of sand/silt/gravel that eventually harden into sedimentary rock.
Minerals act like a cement or “glue”, holding the sediments together as a new rock type.
All three types of rocks can be weathered and reform as new sedimentary rock.
Certain sedimentary rocks will tell you there was an ancient sea where there is now land.
4. METAMORPHIC ROCK
If igneous or sedimentary rock undergoes heating and pressure deep in the earth’s
crust, it transforms into metamorphic rock. It could reform into sedimentary rock.
Rock layers can be folded under other layers moving surface rocks deep down into the crust.
Colliding plates can also compress and fold layers of the crust, creating metamorphic rock.
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CLIPS
PART B - INTERACTIVE SITES
2. TEST YOUR KNOWLEDGE - GO HERE
3. Interactive Rock Cycle... click on "play animation" to move through the cycle