1. You Rock! Well… at least the Earth Rocks!
1 How Rocks Form
2 Igneous Rocks
3 Sedimentary Rocks
4 Metamorphic Rocks

2. How Rocks Form
VOCABULARY
In general, a rock is a group of minerals bound together.
rock
igneous
magma
Igneous, sedimentary, and metamorphic rocks are formed, broken down, and reformed in a recurring process called the rock cycle.
sedimentary
sediment
metamorphic
rock cycle
click image to enlarge

3. 6.2 Igneous Rock
VOCABULARY
Igneous rocks form as molten rock solidifies, as magma deep in the crust or lava at Earth’s surface cool.
felsic
mafic
pluton
Felsic magmas form light-colored, silica-rich rocks. Mafic magmas form dark-colored rocks rich in iron and magnesiums.
batholith
Igneous rock texture depends mainly on the rate at which magma or lava cools.
Granite is igneous rock formed from felsic magma.
Basalt is igneous rock formed from mafic magma.

4. 6.2 Igneous Rock
VOCABULARY
Igneous rocks are grouped into families by mineral composition and texture.
felsic
mafic
pluton
Texture
coarse-
grained
fine-
glassy
porous
Chemical
Composition
felsic
ultramafic
felsic-
intermediate
mafic
batholith
granite
granodiorite
diorite
gabbro
peridotite,
dunite,
pyroxenite
rhyolite
andesite
basalt
obsidian
basalt
glass
most pumice
scoria
diabase

5. 6.2 Igneous Rock
VOCABULARY
Magma that solidifies underground forms various types of igneous intrusions.
felsic
mafic
pluton
Volcanic neck
Laccolith
batholith
Volcano
Stock
Dike
Sill
Batholith

6. Sedimentary Rock
VOCABULARY
Sedimentary rocks form from sediments that result from weathering and erosion of rock at Earth’s surface. They often occur in layers, formed over time as different sediments are deposited on top of each other.
cementation
stratification
fossil

7. Sedimentary Rock
VOCABULARY
Sedimentary rocks are grouped by the type of sediment from which they form: clastic, chemical, or organic.
cementation
stratification
fossil
Clastic: Sandstone
Chemical: Rock Salt Flat
Organic: Limestone Cliffs

8. 6.3 Sedimentary Rock
VOCABULARY
Clastic sediments are often sorted by water action before pressure and mineral cements turn them into rock.
cementation
stratification
fossil
1. A river moves sediment into a lake.
2. Particles are sorted by size. The largest gravels are the first to be deposited, followed by sands, and then silt and clay.
Sands and Gravels
Sands
Silt and Clay
3. Over time, the sediments are buried, compacted, and may be cemented.
Conglomerate
Sandstone
Shale

9. Sedimentary Rock
VOCABULARY
Clastic sediments are often sorted by water action before pressure and mineral cements turn them into rock.
cementation
stratification
fossil
Fossils, ripple marks, mud cracks, nodules, concretions, and geodes features associated with sedimentary rocks.

10. 6.4 Metamorphic Rock
VOCABULARY
Metamorphic rocks form when heat or pressure or both alter parent, or preexisting, rocks.
parent rock
metamorphism
deform
Shale
Slate
becomes
becomes
Phyllite
Schist
becomes

11. 6.4 Metamorphic Rock
VOCABULARY
Metamorphic rocks form when heat or pressure or both alter parent, or preexisting, rocks.
parent rock
metamorphism
deform
Metamorphism can occur across a region, as in mountain building events, or it can occur in smaller local areas.
A metamorphic rock may be described and identified according to its parent rock, mineral composition, and texture.