Fossil Fuel formations

How did Oil form?

OrganicMaterial - NOT dinosaurs! - Although oil formation can also produce some natural gas, the source materials for oil (microscopic marine organisms) are different than those for most natural gas (plant material). • Three drivers are necessary to form oil from dead organic matter: - Time (millions of years) - Temperature - Pressure • Temperature and pressure result from burial under successive sedimentary layers over millions of years. • Thematerialsprogressthrough: 1. Organic Material; which converts to... 2. Kerogen; which becomes... 3. Bitumen; and finally... 4. Oil + Lighter Hydrocarbons + Residue

Coal formation (process)

Present-day coal deposits formed from decomposing woody plant material which accumulated in swamps and deltas primarily during the Carboniferous Period (nearly 300 million years ago) when large regions of the Earth were covered with densely forested swamps. These accumulations, cycled with periods of sand, silt, and mud deposition, left layer upon layer of sediment and decaying plant material. Time High temperature and pressure achieved after deep burial over time caused physical and chemical changes which converted the beds of decaying plant material into coal deposits. Enormous amounts of plant matter formed present-day coal seams; 20 meters of plant material eventually produced a one-meter-thick coal seam.

How did natural gas form?

Source Materials: - Most natural gas was formed from the same woody/peaty (humic) organic material as coal, but some of it was also created from marine micro-organisms (sapropelic) that formed oil. - Only ~1⁄4 of natural gas is associated with oil deposits (found in oil fields), but otherwise is non-associated. • Processes: - Thermogenic: Most of the world's natural gas was the result of continued "cooking" of coal and oil deposits, driving off the smaller more volatile hydrocarbons - mainly methane (leaving longer-chain hydrocarbons behind). Takes millions of years. - Biogenic: Up to 20% of global natural gas reserves may have been formed early in the burial process by microbes in the soil metabolizing buried organic material. Thousands to millions of years to accumulate. - Inorganic/Abiotic: Natural gas has also been theorized to emanate from carbon contained in deep rocks (Thomas Gold), although the prevailing scientific theory is that natural gas deposits are of organic origin.