Presentation on theme: "Sedimentary Rocks CH 3 Prentice Hall p. 82-86 CH 3 Prentice Hall p. 82-86."— Presentation transcript:
Sedimentary Rocks CH 3 Prentice Hall p CH 3 Prentice Hall p
Weathering The process that breaks down rocks at Earth’s surface into sediments. Mechanical (Physical) Freezing and thawing Release of pressure Growth of Plants Actions of Animals Abrasion- grinding away rock by particles of rock. Chemical Chemical Changes Water Oxygen Carbon Dioxide Living Organisms Acid Rain
Erosion The process by which wind,water,ice,or gravity Running water or wind loosen and move rock fragments (sediments). *Moving water * winds * gravity
Deposition Process by which particles (sediments) settle out of water or the wind carrying it. – Sediments- fragments and particles of rocks, and pieces of living things such as shells, bones, leaves and stems. (The pieces from living things form fossils.
Compaction The process that presses rocks together due to gravity and the weight of overlying layers. – Loose Layers – Layers build and become heavier pressing down. – More layers form and add weight, which presses down and compacts the rock. – Creates visible layers
Cementation The process in which dissolved minerals crystallize and glue particles of sediment together. Occurs during compaction. Dissolved minerals fill in the spaces between sediments.
Rock fragments are squeezed together. Grouped by the size of the fragments. – Size- from extremely small clay size to boulders. Clastic Rocks Shale Forms from tiny particles of clay. Very thin layers No cement is needed. Shale is smooth and splits easily into pieces. Sandstone Forms from sand on beaches, the ocean floor, in river beds and sand dunes. Compaction and cementation of sand. Mostly made of quartz Absorbs water easily Conglomerate Forms from a mixture of rock fragments of different sizes. Conglomerate- has rounded edges. Breccia- sharp edges
Forms where the remains of plants and animals are deposited in thick layers. Organic Rocks Coal Forms from the remains of swamp plants buried in water. The weight of each layer squeezes the decaying plants. Millions of years later, coal is formed. Limestone Form from the hard shells of living things. (Calcite) Layers of shells build up. Pressure squeezes the shells together. Dissolved calcite cements the shells together. Chalk
Chemical Rocks Forms when minerals that are dissolved in solution crystallize. Rock Salt Made of halite Forms from evaporation. Gypsum formed from evaporation. Limestone Can form when dissolved calcite comes out of solution.
Uses of Sed. Rocks Sandstone and Limestone have been used for building materials for thousands of years. Easily cut into slabs. Limestone is used in cement. White House is built of Sandstone.