TAR SANDS

Tar sands is a common name of what are more properly called bituminous sands, but also commonly referred to as oil sands or (in Venezuela) extra-heavy oil. They are a mixture of sand or clay, water, and extremely heavy crude oil. The use of the word tar to describe these deposits is a misnomer, since tar is a man-made substance produced by the destructive distillation of organic material. Although it appears similar, the material in tar sands is a naturally-occurring, extremely heavy form of crude oil in which the lighter fractions of the oil have been lost, and the remaining fractions have been partially biodegraded by bacteria. As a result, the term "oil sands" is technically more accurate.
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