1.  Formed from sediments.  Sediments - rock fragments, mineral grains, or animal & plant remains.

2.  These sediments are moved by wind, water, ice or gravity.  Sedimentary rocks represent 7% of the Earth’s crust, but they cover 70% of the Earth’s surface.  Sedimentary rocks are fossil-carrying rocks.

3. What turns sediments into solid rock?  Lithification – process of turning loose sediments into solid sedimentary rocks.

4. What turns sediments into solid rock?  Water or wind breaks down and deposits sediment (erosion & deposition)

5. Compaction  As sediment builds up, the weight of overlying material compresses deeper sediments.  The deeper a sediment is buried, the more it is compacted and the firmer it becomes.

7.  Cementation - Dissolved minerals flow between the particles and cement them together.

8. How can sedimentary layers help us understand the age of fossils?  As sedimentary rocks are deposited, they form horizontal layers.  Scientists know that the layers on top (and the fossils in the top layer) are YOUNGER than the fossils in lower layers.

9. 3 Types of Sedimentary Rocks 1. Detrial 2. Organic 3. Chemical

10. 3 Types of Sedimentary Rocks:  Detrial (also called clastic)—made of broken pieces of other rocks.

11. Examples Shale, Sandstone, Conglomerate, and Breccia

12. Organic—remains of plants and animals are deposited in thick layers.  Ex. Fossil rich limestone is made from the shells of ocean animals; used to make chalk 3 Types of Sedimentary Rocks:

13.  Chemical—minerals dissolved in lakes, seas, or underground water. 3 Types of Sedimentary Rocks: Mineral crystals are made as the shallow water that has flooded the bottom of Death Valley evaporates. Click on image for full size (66K JPG) Courtesy of Martin Miller, University of Oregon

14. Examples  Limestone made when calcite mineral precipitates from sea water.  Rock Salt— made from evaporation of sea waters.