Lecture 2 Notes
Sedimentary Rocks
- rocks that are the result of the processes of
weathering and erosion
- come from sediment of small rock
fragments and organic remains that have
been moved by water, wind or other agents
of erosion. Over a period of time, sediment is
cemented together to form sedimentary rocks.
- can be formed from metamorphic, igneous
or other sedimentary rocks
- account for 75% of the rocks exposed at
Earth's surface
Three types of sedimentary rocks
1. Clastic
Sedimentary Rock
- sedimentary rocks that have been
formed from the fragments of other rocks
- clastic comes from the Greek word
klastos which means "broken@.
Conglomerate rocks are
made of large rock pieces
that have been cemented
together.
* When looking at this rock
type, you can easily see the parts that it has been made of.
.
- Sandstone rocks are made
of fine sand grains
sand has been cemented
together. Rubbing the surface
of sandstone rocks may result
in small grains of sand being
rubbed off of the rock.
-Shale is made up of very fine
grains of clay
*The texture of shale is very
smooth to the touch and can
be broken with your hands
2. Chemical Sedimentary Rock
- is sedimentary rocks resulting from chemical deposits.
- can be rock that formed when water evaporated and
left behind minerals.
- Halite or Rock Salt is a rock that forms as water
evaporates leaving the crystals to form a solid.
- formations you see in caves are made when water drips
from the top of the cave and leaves behind minerals.
*Stalagmites and Stalactites form as mineral rich water
runs off or runs onto them
3. Organic Sedimentary Rocks
- formed from the life processes of living things
or the remains of the organisms.
- Limestone that is formed from the shells of
clams and other
organisms is organic.
* When you write with
chalk on the chalkboard,
you are actually using the
shells of organisms that
lived long ago!
-Coquina is another organic sedimentary rock made from the
sediments of animals shells
- Coal is made from plants that died in swamps
millions of years ago.
* Coal therefore is another example of organic rocks.
Make a Sedimentary
Rock Concept Map
Name:
_____________________________
_______________________
Period:__________________________
Use the following terms to make a concept map:
Sedimentary rock
Compaction
Sandstone
Limestone
Weathering
Halite
Erosion
Conglomerate
Clastic
Shale
Chemical
Cementation
Coal
Sediment
Deposition
Chalk
Organic