1. Biochemical Sedimentary Rocks Most Chemical Sedimentary Rocks have a significant biological component, making a sharp distinction impractical

2. Chemical Sediments Evaporites -Water Soluble Halite Gypsum Calcite Precipitates Example: Ca(sol'n) + SO 4 (Sol'n) = CaSO 4 Gypsum Limestone Iron Formations Alteration After Deposition Dolomite Biogenic Sediments Limestone - Shells, Reefs, Etc. Organic Remains Coal Petroleum

3. Fossil Fuels

4. Coal Seams, Utah

5. Coal Delta, continental environments Carbonized Woody Material Often fossilized trees, leaves present

6. Plant Fragments Are Often Visible in Coal

7. Petroleum A hydrocarbon molecule What organisms make these? Answer: None

8. Petroleum Lots of organisms make these, however Fatty Acids Probable source: Marine plankton

9. Petroleum Traps

10. Methane Hydrate

11. Gas Hydrates Hydrocarbons trapped in cage of water molecules Freeze above 0 C under moderate pressure Solid gas hydrates occur in marine sediments (“yellow ice”) Potentially huge energy resource Possible role in climate change?