1. Sedimentary Rock

2. Sedimentary Rock Sedimentary rock is created when existing rock breaks downinto sediments, and then the sediments are recombined by compaction and cementation 3. Sedimentary Rock Sediments are created by three forces: Weathering Erosion Deposition 4. Weathering Weathering is any process that breaks down rock. There are two types of weathering Chemical weathering Mechanical weathering 5. Chemical Weathering Chemical Weathering is the transformation of rock intoone or more new compounds Water is the most important agent of chemical weathering 6. Mechanical Weathering Mechanical weathering occurs when physical forces breakrock into smaller and smaller pieces without changing its composition 7. Mechanical Weathering Three forces account for the majority of mechanicalweathering: Frost wedging Unloading Biological Activity 8. Frost Wedging When liquids freeze they expand, causing rock to breakapart. 9. Unloading Unloading occurs when pressure is removed from a rockbody causing it to expand and break 10. Biological Activity The activities of plants and animals can cause rock tobreak apart For example tree roots can break through rock layers, orborrowing animals creating holes in rock. 11. Erosion Erosion is the removal of rock and its movement by water,wind, ice, or gravity. 12. Deposition When water, wind, ice or gravity loses energy the sedimentsare released and deposited in a new area. Sediments are deposited according to size, with largersediments being released first 13. Sedimentary Rock Compaction and cementation are the two processes thatchange sediment into sedimentary rock. 14. Compaction Compaction is a process that squeezes, or compactssediments 15. Cementation Cementation takes place when dissolved minerals aredeposited in tiny spaces among the sediments. These minerals hold the sedimentary rocks together 16. Classification of Sedimentary Rock Sedimentary rocks like igneous rock can be classified intotwo groups based on how the form: Clastic Sedimentary Rock Chemical Sedimentary Rock 17. Clastic Sedimentary Rock Clastic Sedimentary Rocks are created when weatheredbits of rocks or minerals are cemented together 18. Chemical and Biochemical Sedimentary Rocks Chemical Sedimentary rocks are created when dissolvedminerals precipitate from water solutions Biochemical Sedimentary rocks are created when living oronce living materials are cemented together 19. Features of Sedimentary Rock Sedimentary rock can have unique features that can help usinterpret the history of the Earth. Some Features include: Ripples Mud Cracks Fossils