Rock Cycle Notes
Rock – earth material made up of minerals and
organic matter (remains of once living
organisms)
Rock Cycle – a continuous process by which
rocks are created, changed from one form to
another, destroyed, and then formed again.
3 Types of Rocks
• Igneous
• Sedimentary
• Metamorphic
Igneous Rocks
• Formed from molten material (magma)
• Classification: Extrusive or Intrusive
• Extrusive igneous rock- comes out of a
volcano, has small crystal grains because it
cools QUICKLY
• Intrusive igneous rock- does not come out of
the crust/underground, cools SLOWLY so
crystals have to form and grow
EXAMPLES
• Extrusive Igneous Rock
(Obsidian)
• Intrusive Igneous Rock
(Granite)
Weathering, Erosion, & Deposition
Weathering – break down of rocks
Erosion – process in which rocks are transported
from one location to another location by wind,
water, or ice
Deposition – geological process by which
sediments, soil, and rocks are added to a
landform or landmass
Igneous Rocks
Igneous rocks can be worn away by water and
wind (weathering). Erosion is where the
weathered bits are carried away. Deposition
occurs when the weathered bits are dropped.
Sedimentary Rocks
• the weathered bits are
carried away by water
and are dropped out as
the water flows. The
biggest particles drop out
first. This is how
sediments build up and
accumulate.
Lithification – process by
which sediments compact
under pressure to form rock
• Sedimentary rocks form
from the compaction and
cementation of sediments
and weathered rocks
Metamorphic Rocks
• Formed by heat and pressure
• Can occur at subduction zones or in close
proximity to a magma chamber
• Recrystallization - change in the texture
(appearance of rock) because of increased
temperature and pressure
• Classification: Regional and Contact
Metamorphism
Metamorphic Rocks
• Regional Metamorphism – caused by high
temperature and high pressure with deep
burial
• Contact Metamorphism – Caused by high
temperature only near igneous
intrusions/magma chambers
Contact Metamorphism
Regional Metamorphism