oil shale

noun Geology.

1. a black or dark-brown shale or siltstone rich in bitumens, from which shale oil is obtained by destructive distillation.

noun

1. a fine-grained shale containing oil, which can be extracted by heating

1. A fine-grained black or dark brown shale containing hydrocarbons in the form of kerogen. When heated, oil shale yields petroleum or natural gas.