Sedimentary Rocks Origin u Comprise 75 of the

Sedimentary Rocks

Origin u Comprise 75% of the Earth’s surface u Formed when sediments become compacted and cemented together u Usually has layers called strata The highest layer has the least pressure. The lowest layer has the most pressure.

Compaction u What does compaction mean? – Layer upon layer of sediment builds up and the pressure from the upper layers pushes down on the lower layers. – Only SMALL sediments will stick together to form rock

Cementation u What does it mean? – Water soaks through soil and rock. The water dissolves minerals in soil and rock. – The solution of minerals and water moves between the sediments. – The sediments stick together when the minerals crystallize. – Common with LARGE sediments

Classification u Sedimentary rocks are classified in 3 ways… 1. Clastic Sedimentary Rocks 2. Chemical Sedimentary Rocks 3. Organic Sedimentary Rocks It’s by the way they are formed!!! WHAT?

Clastic Sedimentary Rock u Made from broken fragments of other rocks. – Conglomerate = large/round fragments – Breccia = large/sharp fragments Breccia Conglomerate

Chemical Sedimentary Rock u Formed from minerals crystallizing out of a solution u The solution is made of minerals and water. Halite (Rock Salt)

Organic Sedimentary Rock u Rocks formed from once-living (organic!) things. Organic Limestone Ocean animals called coral create huge deposits of limestone. As they die, their skeletons collect on the ocean floor.

Stratification u The process in which sedimentary rocks are arranged in layers.

Stratification