1. EARTH MATERIALS EQ:What are sedimentary rocks? Rocks that form from the burial, compression, and cementation (lithification) of the deposits of weathered remains of other rocks (clastic); by deposition of the results of biogenic activity (organic); and by precipitation from solution (chemical). Sedimentary Rocks CLASSROOM UNSQUARED

2. The Formation of Sedimentary Rocks Exposed rock Weathering Erosion Deposition Burial Uplift Erosion Exposure Weathering is the physical or chemical breakdown of exposed rock (sediments). Sediments + decayed organic matter = soil.

3. Weathering

4. Sediment Grain Size

5. Erosion is the movement of sediments from one location to another. Agents of erosion: Moving water - river systems (major) Wind – deserts, ergs Glaciers – high elevation and latitude Gravity – avalanches, slump, creep The Formation of Sedimentary Rocks

6. Erosion

7. Environments of Deposition

8. Deposition, Burial, Compaction/Cementation

9. Sedimentary Rock Features Strata Fossils Trace Fossils (tracks, burrows) Ripple marks (currents) Mud cracks Graded bedding (storm deposits) Cross-bedding (tilted dep. surface)

10. Sedimentary Rocks (Identification Key)Identification Key NameClassSediment SandstoneClasticSand grains (quartz) SiltstoneClasticSilt grains ConglomerateClasticRounded Sand / Gravel / Pebbles BrecciaClasticAngular Fragments ShaleClasticClay CoalOrganicOrganic matter LimestonePrecipitateCaCO 3 Shell LimestoneOrganicCaCO 3 ChertPrecipitateSiO 2