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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.
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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
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 swamps millions of years ago. * Coal therefore is another example of organic rocks.