Sedimentary Rocks February 2012

California Standard 3.c. Students know how to explain the properties of rocks based on the physical and chemical conditions in which they formed, including plate tectonic processes.

Today’s Objectives 1.List the three main categories of sedimentary rocks, and describe how rocks form in each of these categories. 2.Identify characteristics of sedimentary rocks using visual observations.

Sediments are eroded from other rocks to make these rocks Compacted – weight of layers of sediment Cemented – water carries dissolved minerals through sediment that acts like cement Sediments are compacted and cemented to make a sedimentary rock Interactives. The Rock Cycle. The Rock Cycle

Sediments Compacted and Cemented

Three types of sedimentary rocks: ▫Clastic ▫Chemical ▫Organic

Sediments Compacted and Cemented Clastic Chemical Organic

Clastic Sedimentary Rocks – composed of pieces of other rocks. Name depends on size of the pieces.

Conglomerate Clastic Sandstone Shale or Mudstone

Sediments Compacted and Cemented Clastic Conglomerate SandstoneShale Chemical Organic

Chemical Sedimentary Rocks – composed of minerals once dissolved in water that precipitate out of water due to a change in temperature.

Chemical Limestone Evaporites

Sediments Compacted and Cemented Clastic Conglomerate SandstoneShale Chemical LimestoneEvaporites Organic

Organic Sedimentary Rocks – formed from the remains of living things Coal Coal is formed from dead plants, usually in swampy areas, left to rot and covered with a lot of sediment for thousands or millions of years.

Sediments Compacted and Cemented Clastic Conglomerate SandstoneShale Chemical LimestoneEvaporites OrganicCoal

Important facts about sedimentary rocks: 1.Created from sediments weathered and eroded from other rocks 2.Only rocks that have fossils 3.Only rocks that show water and sometimes wind patterns (ripples) 4.Only rocks that have layers (sediment is deposited by water, wind, or ice in layers)

Fossils

Ripple Marks

Layers

1.Go back and review what you completed on the table for the Igneous Rocks. Are igneous rocks layered? Leaved the banded boxes empty for now. 2.Complete your table for the Sedimentary Rocks. You may take the containers of rocks to your table to share with other people, but please return the rocks to the correct container, and return the container to the place where you obtained it. You have about 20 minutes to look at the Sedimentary Rocks

The Earth started here with Magma