3.3 – Sedimentary Rocks

Videos/Websites http://www.youtube.com/watch?v=p1F4J8uZUQc&feature =relmfu http://geology.com/rocks

Do Now What is compaction?

Do Now What is compaction? The process by which sediments are squeezed together by the weight of overlying materials driving out water.

Sediments Angular Key Words

Vocab Words Erosion Deposition Compaction Cementation Chemical Sedimentary Rock Clastic Sedimentary Rock Vocab Words

Sedimentary Rocks Sedimentary rocks form when solids settle out of a fluid such as water or air. The rocks will eventually become cemented to form sedimentary rocks. Clastic vs. Chemical

Formation Weathering Erosion Deposition Weathering is any process that breaks rocks into sediments. This is the first step in the formation of sedimentary rocks Erosion Involves weathering and the removal of rock. Agents of erosion – water, wind, ice, or gravity Deposition When an agent of erosion loses energy, it drops the sediments. Sediments are dropped according to size, the larger ones will deposit first, and the smaller ones last.

Formation Compaction Cementation A process that squeezes, or compacts, sediments. Caused by the weight of sediments. Much of the water in the sediments is driven out. Cementation Takes place when dissolved minerals are deposited in the tiny spaces among sediments. Sometimes the cement holding the rocks together are easily seen, other times it is microscopic.

Classification of Sedimentary Rocks Classified by the way they form. Clastic Sedimentary Rocks – rocks made of weathered bits of rocks and minerals. Chemical Sedimentary Rocks – rocks formed when dissolved minerals precipitate from water solutions.

Clastic Sedimentary Rocks Many different minerals are found in clastic rocks. Most common are clay and quartz. Can be grouped according to the size of the sediments in the rocks. When rounded, gravel-size or larger particles make up most of the rock, the rock is called Conglomerate. If the particles are angular, the rock is called Breccia. Sandstone is the name given to rocks when the sediments are sand-size grains. Shale, the most common sedimentary rock, is made of very fine-grained sediments. Siltstone is another fine-grained rock.

Clastic Sedimentary Rocks

Chemical Sedimentary Rocks These are the sedimentary rocks that have fossils in them. Precipitation that generally occurs during the formation of chemical sedimentary rock is from evaporation of a solid product. Limestones Rock Salt Chert Flint Rock Gypsum Coquina

Features The many unique features of sedimentary rocks are clues to how, when, and where the rocks formed. Fossils are found in chemical sedimentary rocks and show us our past.

Classification Chart

Group Activity On page 79, use that table to fill in the blanks on your group paper and place it in your folder when complete.