Roger N. Anderson, a professor at the Lamont-Doherty Earth Observatory at Columbia University, explains.

Plate tectonics determines the location of oil and gas reservoirs and is the best key we have to understanding why deserts and arctic areas seem to hold the largest hydrocarbon reserves on earth. But there are other important locations of large reserves: river deltas and continental margins offshore. Together, these four types of areas hold most of the oil and gas in the world today.

Oil and gas result mostly from the rapid burial of dead microorganisms in environments where oxygen is so scarce that they do not decompose. This lack of oxygen enables them to maintain their hydrogen-carbon bonds, a necessary ingredient for the production of oil and gas. Newly developing ocean basins, formed by plate tectonics and continental rifting, provide just the right conditions for rapid burial in anoxic waters. Rivers rapidly fill these basins with sediments carrying abundant organic remains. Because the basins have constricted water circulation, they also have lower oxygen levels than the open ocean. For instance, the Gulf of California, an ocean basin in development, is making new oil and gas in real time today. The Gulf of Mexico is also a great example of new oil and gas formation in a restricted circulation environment (see image at right above).

The same plate tectonics that provides the locations and conditions for anoxic burial is also responsible for the geologic paths that these sedimentary basins subsequently take. Continental drift, subduction and collision with other continents provide the movement from swamps, river deltas and mild climates--where most organics are deposited--to the poles and deserts, where they have ended up today by coincidence. In fact, the Libyan Sahara Desert contains unmistakable glacial scars and Antarctica has extensive coal deposits--and very likely abundant oil and gas--that establish that their plates were once at the other ends of the earth (see image at right).

Plate tectonics is also responsible for creating the "pressure cooker" that slowly matures the organics into oil and gas. This process usually takes millions of years, giving the oil and gas deposits plenty of time to migrate around the globe on the back of plate movements. Because these hydrocarbons are much more buoyant than water, they eventually force their way to the surface. Alternatively, rifting, collisions between land masses, and other tectonic forces can free the mature oil and gas from deep within sedimentary basins and then trap these organic fluids in reservoirs before they escape to the earth's surface. We know these reservoirs as oil and gas fields.

7 Comments

1. 1. Mrbridge 05:50 PM 5/27/08

   Is there any relationship between movment of the plates and the extraction of oil, or lack of?

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2. 2. gregorious maximious 06:37 PM 9/15/08

   How did the oil end up in Alberta and Saskatchewan which are in the middle of the North American Plate? Did this happen hundreds of millions of years ago, long before the dinasors because oil has to form in oceans right?
   

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3. 3. kMI in reply to gregorious maximious 06:49 PM 7/4/09

   gregorious m,
   Oil and gas source rocks can form in oceans, river deltas, or less commonly in rivers or lakes. Some of the oil and gas in Canada and the US Rockies region is sourced from Mesozoic rocks (time of the dinosaurs), when a large interior seaway and associated river deltas, like an extension of the gulf of mexico, covered the area, before and during the time the mountains were being uplifted. Some of the oil and gas is sourced from much earlier Paleozoic rocks, when the continent was rotated and south of its current position due to plate tectonics, and shallow seas covered many areas. Hope that helps!

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4. 4. OLORUNTELEA 07:51 PM 12/26/09

   What is the relationship between plate tectonics and hydrocarbon production ?

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5. 5. OLORUNTELEA 08:10 PM 12/26/09

   What is the relationship between plate tectonics and hydrocarbon production

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6. 6. clarkcramer 10:46 PM 5/27/10

   Thinking about the recent oil spill in the gulf, the volume and the pressure the oil is under, I wonder if earthquakes could or have ever release large volumes of oil on land or sea. (I know that extracting oil can induce small earthquakes--but I'm asking the opposite question.)

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7. 7. twirledpeas69 08:22 PM 5/29/10

   If you asked a savage what the purpose of oil is in a machine, even he would know its the blood. The blood's purpose is to supply coolant to the machine. Same as in a tectonic plate. As to the ultimate results of having these pockets of oil located at these plate boundaries, it would seem beneficial to have a liquid of this nature to absorb heat from the boundary and allow it to be more evenly distributed to the outlying areas.
   It could also 'bleed' into nearby emptier structures to stop rampant movement of plates.
   
   Black Blood of the Earth.
   
   There is no scientific proof that extraction of oil has any significant effect on a tectonic plate. There is also no scientific proof that there are significant effects on tectonic plates from anything other reactions with the earth's core, the moon's gravitation and the sun's gravitation, and even then I doubt we would find those results significant if we only chose to measure even a human lifetime of data.

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