Bell Ringer What type of rock is formed when you melt a rock (magma or lava) and then cool it?  Igneous  Sedimentary  Metamorphic

Sedimentary Rocks

Where are sedimentary rocks found?  All over the world and NYS Where do sedimentary rocks form?  Under large bodies of water Why do sedimentary rocks form layers?  Sorting of sediments (strata)

Sedimentary rocks form from sediments  They form in two ways 1. from the result of weathering (breaking into smaller pieces)and erosion (moving the sediments) 2. organic processes (from once living things)

3 types of sedimentary rocks: 1. Clastic – form from rock fragments that are stuck together

Cementation Makes the sediments stick together Most common cements: Quartz Calcite Hematite

Clastic Sedimentary Rocks are Identified by Particle Size!!!!!!! Conglomerate: Large particles (rounded) Breccia: Large particles (angular)

Other Clastic sedimentary rocks: Sandstone: Sand ( cm) Siltstone: Silt ( cm) Shale: Clay (<.0004cm)

As sediment layers are added, pressure on underlying sediments compresses the sediment, causing compaction  Imagine squeezing water out of a sponge Example: Shale – forms from silt or clay sediments that are compressed, squeezing the water out.  Shale is roughly 70% of all sedimentary rocks. Geology Kitchen

3 types of sedimentary rocks: 2. Chemical – dissolved materials from weathering later get deposited from precipitation out of solution

3 types of sedimentary rocks: 3. Organic – result from biological processes.  Some form from the remains of plants and animals.  Example: coal

Some form from life underwater using calcite to form shells. These shells can get cemented and compacted also, forming limestone. Geology Kitchen

Characteristics of sedimentary rocks ONLY rocks that can contain fossils Often layered (contains sediments)