Day Lecture 2 Notes Date

Sedimentary Rocks - rocks that are the result of the processes of weathering and erosion. - account for 75% of the rocks exposed at Earth's surface

Sedimentary rock comes from fragments of other rocks that have been weathered, eroded, deposited, compacted, and cemented

- 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 - 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. Nonclastic 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

*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 organisms or the remains of the organisms.

- Limestone that is formed from the shells of clams and other organisms is organic

- Coal is made from plants that died in swampsmillions of years ago.

* Coal therefore is another example of organic rocks.