tar pit

tar pit

n.

An accumulation of natural tar or asphalt at the earth's surface, especially one that traps animals and preserves their bones.

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tar pit

An accumulation of natural tar or asphalt at the Earth's surface, especially one that traps animals and preserves their hard parts. Tar pits form when petroleum in subterranean petroleum-bearing rocks oozes up to the surface. As it rises, the petroleum loses its volatile components, forming a thick tar or asphalt deposit.

Thesaurus

Noun

1.

tar pit - a natural accumulation of bitumens at the surface of the earth; often acts as a trap for animals whose bones are thus preserved cavity, pit - a sizeable hole (usually in the ground); "they dug a pit to bury the body"