Igneous, Sedimentary &
Metamorphic Rocks
Sedimentary-sandstone
Igneous- diorite
Metamorphic- gneiss
1. What is a Rock?
• Naturally Occurring (not man made)
• Solid
• Mixture of minerals other
organic matter
2. What makes a rock
different from a mineral?
Rock
Both
Mineral
Made of one or more
minerals
Solid
Made of one type of element
Random crystal or no
crystal structure
Naturally Occurring
Orderly crystal structure
←Granite=
Quartz+ Feldspar+
Muscovite
Igneous
Rocks
3.
Magma & Lava form different
types of igneous rock
• Igneous rock is classified by where rock
forms
Intrusive vs. Extrusive
forms when
magma/lava
forms when magma
cools inside the earth
surface
exits &
cools on earth’s
surface
Intrusive Vs. Extrusive
Diorite
Granite
Basalt
Pegmatite
Gabbro
Rhyolite
Andesite
Scoria
4. Igneous Rocks:
Crystal size & Cooling Time
Location of Rock
Crystal Size
Intrusive (in earth)
Extrusive (earth surface)
Large crystals
Small crystals
Longer cooling time
Shorter cooling time
Picture
Cooling time
Sedimentary
Rock
5. Some rocks form from
rock particles
•Sediment= materials that settles
out of water or air
– Materials can be:
• tiny pieces of rock
• broken minerals
• pieces of plants and animal remains
6. How do sedimentary
rocks form?
• Sediments pile on top of each
other on land or in water
• As sediments pile, they become
compacted and cement together
Sedimentation Process
Sedimentary rock layers
Rock layers
www.eos.ubc.ca/courses/eosc320/eosc320.htm
7. Some rocks form from
plants or shells
• Coal- created from plant remains (dead
wood, bark, leaves, stems, and roots)
– The coal we use today started forming millions of
year ago in swamps
• Limestone- created from
the shells and skeletons of
ocean organisms
Can you see the plant remains?
http://www.geology.pitt.edu/PAgeo/coal.html
Limestone formation
Metamorphic
Rocks
8. Metamorphic Rocks
• Heat and pressure change rocks
– The original rock is called the parent
rock
– The new rock formed is called the
metamorphic rock
– Heat and pressure change the structure
of the parent rock and their minerals
recrystallize
9. Examples of Metamorphic
Rocks
Parent Rock= Shale
Metamorphic Rock = Slate
Increase Temp. & Pressure
Examples of Metamorphic
Rocks
Parent Rock = Limestone
Metamorphic Rock = Marble
Increase Temp. & Pressure
Examples of Metamorphic
Rocks
Parent Rock = Mica
Metamorphic Rock = Phyllite
Increase Temp. & Pressure
10. When a rock forms does
it stay that way forever?
NO!!!!!!
• Rocks are always changing by processes
like:
– Weathering
– Erosion
– Compaction
– Heat
-Melting
-Cooling
-Cementation
-Pressure
Composition of Igneous
Rocks
•Igneous rocks are mainly composed
of silicate minerals (quartz,
feldspar,etc.)
•Rocks with high silicate levels-are
typically light in color
•ex: granite, rhyolite
•Rocks with low silicate levels- dark
in color
•ex: gabbro and basalt
Igneous rocks make long-lasting landforms
1. Intrusive rock formations-as magma pushes up
toward Earth’s surface, it makes channels and
other formations underground.
2. Extrusive rock formations• builds plateaus when erupting from long crack
• gently sloping volcanoes (Hawaiian
islands)
• cone-shaped volcanoes
(1). contains greater amount of silica
(2). erupts explosively
(3). Mount St. Helens is an example
•Rock cycle-the set of natural
processes that form,
change, break down, and reform rocks
Our world is built of rocks
Rocks have many purposes
1. used to build houses and skyscrapers
2. great source of metals
3. used to carve statues and other works
of art
11. Rock Cycle
Rock Cycle animation