Organic-rich sedimentary rocks are a specific type of sedimentary rock that contains significant amounts (>3%) of organic carbon. The most common types include coal, lignite, oil shale, or black shale. The organic material may be disseminated throughout the rock giving it a uniform dark color, and/or may be present as discrete occurrences of tar, bitumen, asphalt, petroleum, coal or carbonaceous material. Organic-rich sedimentary rocks may act as source rocks which generate hydrocarbons that accumulate in other sedimentary "reservoir" rocks (see oil sands and petroleum geology).
Famous quotes containing the word rocks:
“If all else perished, and he remained, I should still continue to be; and if all else remained, and he were annihilated, the universe would turn to a mighty stranger. I should not seem a part of it.... My love for Heathcliff resembles the eternal rocks beneath—a source of little visible delight, but necessary. Nelly, I am Heathcliff—he’s always, always in my mind—not as a pleasure, any more than I am always a pleasure to myself—but as my own being.”
—Emily Brontë (1818–1848)