1. Ch. 3 The Rock Cycle
Intro

2. ***The melting of any rock type leads to the production of magma.
 Magma - molten material deep beneath Earth’s surface.
 Lava - magma that reaches the surface.
***The melting of any rock type leads to the production of magma.

3. IGNEOUS ROCKS Formation Igneous Rocks form when Magma or lava Cools.
Cooling can occur either
below or above the surface!

4. Formation of Igneous Rocks
Intrusive - magma hardens
beneath Earth’s surface (granite).
Cools slowly
Have large crystals/grains
Extrusive - formed when lava
hardens at surface (pumice, rhyolite).
Cools quickly
Have no/small
crystals/grains

5.  Weathering - rocks broken down by water, air & living things.
 Sediments -weathered pieces of Earth elements.
 Erosion - sediments are transported by water, wind, ice or gravity.

6. SEDIMENTARY ROCKS
Formed from particles or sediments that have been transported & deposited by wind, water, ice, gravity.
Over time, these particles become pressed or cemented together to form rocks.
Ex: sandstone

7. Formation of Sedimentary Rocks
 1. Weathering, Erosion & Deposition
• After weathering and Erosion occur sediments must be deposited!
• Deposition - an agent of erosion (water, wind, ice, or gravity) loses energy & drops sediments.
 2. Compaction & Cementation
• Compaction - process that squeezes sediments by the weight of overlying materials driving out water.
• Cementation – Solidification of sediments by the deposition of dissolved minerals which act like a “glue.”

8. METAMORPHIC ROCKS
Formed when chemical reactions, heat, and/or pressure change existing rocks into new rocks.
(physical & chemical properties usually quite different from original.)
meta- means change, morph means form.
(Ex: marble, schist, gneiss (pronounced “nice”)

9. Agents of Metamorphism
 Heat - provides energy needed to drive chemical reactions.
 Pressure - causes a more compact rock with greater density.
How does this happen ?
 Contact metamorphism: magma moves into rock
 Regional metamorphism: large-scale deformation
Direct pressures occur during mountain building
Occurs near a body of magma
Changes are driven by a rise in
temperature
Produces greatest volume of metamorphic rock.

10. Energy That Drives the Rock Cycle
Processes driven by heat from
Earth’s interior are responsible
for forming both igneous &
metamorphic rocks.
Weathering & erosion are
external processes powered
by energy from the Sun,
produce sedimentary rocks.

11. SEDIMENTARY ROCKS METAMORPHIC ROCKS
Weathering and erosion
Heat and pressure
Melting
Cooling
Compaction, cementation, and lithification
IGNEOUS ROCKS
MAGMA
SEDIMENTS
SEDIMENTARY ROCKS
METAMORPHIC ROCKS