1. terrestrial organics: vascular plants: “humic”; cellulose, lignin, carbohydrates marine/lacustrine organics: phytoplankton, zooplankton; “sapropel”; fats, resinous, waxy

2. Peat Lignite Sub-bituminous Bituminous Anthracite Graphite H2OH2O H:C ratio Methane evolved 80 o C 50 o C 20 o C 160 o C 240 o C Coal Rank

4. terrestrial organics: vascular plants marine organics: phytoplankton, zooplankton

5. marine organic matter kerogen petroleum liquids methane evolved 120 o C (decarbox- lyation) asphalt, bitumen H:C ratio 60 o C 20 o C 90 o C 200 o C carbon dioxide evolved km buried 1.0 2.0 3.0 4.0 5.0

6. “oil shale” - kerogen

8. alkanes – paraffin, straight – chain hydrocarbons

9. aromatics – more soluble in water, smelly, toxic

10. cycloparaffins