or tar pit
seepage of natural tar or asphalt, especially an accumulation that has acted as a natural trap into which animals have fallen and sunk and had their bones preserved.
Origin of tarpit
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.