Download Sedimentary Rocks

Rocks and the
Rock Cycle
What Is a Rock?
A. Solid
B. Formed in nature
C. Usually a mixture of minerals
D. Can have organic matter
E. Identification is based on mineral
content and texture
Characteristics
Texture = size, shape, & arrangement
of grains
Grains = rock particles (i.e. minerals)
Igneous Rocks
Igneous –
formed from
cooling and
hardening of
magma or lava
Igneous Rocks
Crystal Size – Rate of cooling
determines size of crystals
Fast cooling: no
crystals or
small crystals
Slow cooling:
large crystals
Igneous Rocks
Extrusive: Cool Fast Glassy
Small Crystals OR
No Crystals
Finegrained
Examples:
Extrusive
• Obsidian
Examples:
Extrusive
• Pumice
Examples: Extrusive
• Basalt
Igneous Rocks
Intrusive: Cool
slowly
Large crystals
Example: Granite
Sedimentary Rocks
Sedimentary –
formed from
compaction and
cementation of
sediments,
usually in water
Sedimentary Rocks
Most sedimentary rocks are formed through a
series of processes: erosion, deposition,
compaction, and cementation.
Sed. Rocks often
form into layers
Sedimentary Rocks
Clastic – pieces of rock pressed and stuck
together
Conglomerates:
rounded gravelsize fragments
Breccia =
fragments of rock
angular w/ sharp
corners
Sedimentary Rocks
Clastic – pieces of rock pressed and stuck
together
Sandstones =
sand-sized grains
cemented
together
Shale =
small claysized
particles
cemented
together
Sedimentary Rocks
Organic – formed from remains of plants
& animals
Coal
Limestone
Sedimentary Rocks
Chemical – dissolved minerals come out
of solution and form crystals
Rock Salt
Limestone
Metamorphic Rocks
Metamorphic formed when
existing rocks
are changed by
heat, pressure
or chemical
action
Contact Metamorphism
–hot magma pushes through
existing rock, heating
surrounding rock and changing it
to metamorphic.
Metamorphic Rocks
Foliated Rocks: “Stripes”
Have visible layers
Mineral grains are flattened and aligned
when pressure is added
Parent Rock
Meta. Rock
PRESSURE
Metamorphic Rocks
Gneiss has banded foliation
Granite
Gneiss
Gneiss
Metamorphic Rocks
Slate has banded foliation
Shale
Slate
Slate
Metamorphic Rocks
Schist has
banded
foliation
Metamorphic Rocks
Non-foliated Rocks: These DO
NOT have layers of crystals
Sandstone
Quartzite
Metamorphic Rocks
Non foliated
Limestone
Marble
The Rock Cycle
A
continuous
process in
which rocks
change
from one
type to
another.
Why does the rock
cycle have no
beginning and no
end?
Sedimentary
Rocks
Clastic
Nonclastic
Formed by
compaction &
cementation
of sediments
such as
Angular
(sharp
edges)
rock
pieces
Round
rock
pieces
Sand
Clay
Shale
Breccia
Sandstone
Conglomerate
Chemical
Organic
Formed by
evaporation
or
precipitation
Formed
from once
living
organisms
Rock
Salt
Coal
Limestone
Heat
Types of
rocks
changed
Changed
by
Pressure
Metamorphic
Rocks
Chemical
Action
Foliated
Sedimentary
Metamorphic
Texture
Minerals
arranged
in bands
Igneous
Nonfoliated
Minerals
not
arranged in
bands
Examples
Schist
Gneiss
Slate
Quartzite
Marble
Sandstone
Sedimentary
Limestone
Sedimentary
Formed
From
Various,
Shale
Sedimentary
Granite
Igneous
Shale
Sedimentary