Asked by kriscisf | 17th Nov, 2008, 08:48: PM

Expert Answer:

Petrol is a fossil fuel. All fossil fuels are the result of biological decay. Both animals and plants are laden with a rich variety of fats and oils, and fossil fuels are the result of being under heat and pressure in the Earth.

Fossil fuels of all types are found under both land and sea.

Geologists view crude oil and natural gas as the product of compression and heating of ancient organic materials (i.e. kerogen) over geological time. Formation of petroleum occurs from hydrocarbon pyrolysis, in a variety of mostly endothermic reactions at high temperature and/or pressure.

Today's oil is formed from the preserved remains of prehistoric zooplankton and algae, which had settled to a sea or lake bottom in large quantities under anoxic conditions (the remains of prehistoric terrestrial plants, on the other hand, tended to form coal).

Over geological time the organic matter mixed with mud, and was buried under heavy layers of sediment resulting in high levels of heat and pressure (known as diagenesis). This caused the organic matter to chemically change, first into a waxy material known as kerogen which is found in various oil shales around the world, and then with more heat into liquid and gaseous hydrocarbons in a process known as catagenesis.

Answered by  | 18th Nov, 2008, 01:06: PM

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