The most significant known deposits of tar sands occur on the North and South American Continents. These are the Athabasca deposit in Alberta, Canada, which contains over 700 billion barrels of oil in place(9,12431 ); The Orincoco Tar Belt in Venezuela, which contains over 600 billion barrels of hydrocarbons in place(1,12431 ); the Llanos area of Columbia, about which little is known, but which is believed to hold as much as a trillion barrels of oil (1,12431 ); and five Utah deposits which hold an estimated total of up to 29 billion barrels of oil (10).