1. Sedimentary Rocks
CH 3 Prentice Hall p

2. Mechanical (Physical)
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

3. Erosion
The process by which wind,water,ice,or gravity Running water or wind loosen and move rock fragments (sediments).
*Moving water * winds * gravity

4. 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.

5. 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

6. 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.

7. Clastic Rocks
Rock fragments are squeezed together. Grouped by the size of the fragments.
Size- from extremely small clay size to boulders.
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

8. Organic Rocks
Forms where the remains of plants and animals are deposited in thick layers.
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

9. 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.

10. 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.