Download Sedimentary Rocks

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From Sediment to Rock
Sedimentary rock forms from particles
deposited by water, wind, and ice.
Sediment is small, solid pieces of material
that comes from rocks or living things.
Water, wind, and ice can carry sediment
and deposit it in layers.
• But what turns these sediments into solid
rock? Let’s see……
What turns sediments into solid rock?
• Step 1 - Erosion
• Step 2 - Deposition
• Step 3 - Compaction
• Step 4 - Cementation
Erosion
• Step 1 - Erosion
Erosion occurs when running water or wind
loosen and carry away the fragments of
rock.
What turns sediments into solid rock?
• Step 2 - Deposition
• Eventually, the moving water or wind slows and deposits
the sediment.
Deposition is the process by which sediment settles out
of the water or wind carrying it.
What turns sediments into solid rock?
• Step 3 - Compaction
• Gradually, over millions of years, thick layers of sediment
build up. These layers are heavy and press down on the
layers beneath them.
Compaction is the process that presses sediments
together.
What turns sediments into solid rock?
• Step 4 - Cementation
Cementation is the process in which
dissolved minerals crystallize and glue
particles of sediment together.
• It often takes millions of years for
compaction and cementation to transform
loose sediments into solid sedimentary
rock.
What turns sediments into solid rock?
Types of Sedimentary Rock
There are three major groups
of sedimentary rocks:
1. Clastic rocks - rock fragments are
squeezed together.
Clastic – made of fragments of rock
cemented together with calcite or quartz
Breccia is a term most often
used for clastic sedimentary
rocks that are composed of
large angular fragments
(over two millimeters in
diameter).
The spaces between the
large angular fragments can
be filled with a matrix of
smaller particles or a mineral
cement that binds the rock
together.
Types of Sedimentary Rock
There are three major groups
of sedimentary rocks:
2. Organic rocks - remains of plants and
animals are deposited in thick layers.
• As layer upon layer of plant remains
build up, the weight of the layers
squeezes the decaying plants.
• Over millions of years, they slowly
change into coal.
Organic sedimentary – remains of plants and
animals
Coal is an organic
sedimentary rock that
forms from the
accumulation and
preservation of plant
materials, usually in a
swamp environment.
Coal is a combustible rock
and along with oil and
natural gas it is one of the
three most important
fossil fuels.
Types of Sedimentary Rock
There are three major groups
of sedimentary rocks:
3. Chemical rocks - when minerals that are
dissolved in a solution crystallize.
Chemical sedimentary – minerals crystallize
out of solution to become rock
Limestone is a sedimentary rock
composed primarily of calcium
carbonate (CaCO3) in the form of
the mineral calcite. It most
commonly forms in clear, warm,
shallow marine waters.
It is usually an organic
sedimentary rock that forms
from the accumulation of shell,
coral, algal and fecal debris.
Uses of Sedimentary Rocks
• You may be surprised to learn that the White House in
Washington, D.C., is built of sandstone.
• Limestone also has many industrial uses.
• Limestone is also used in making cement.