But scientists quickly learned that they hadn't quite found rocks formations either; they'd discovered an asphalt volcano, a geologic formation that's spotted with little frequency.
Asphalt volcanos aren't traditional volcanoes, in that they don't spew molten lava like Mount St. Helens. They are the product of the same volcanic forces that push oil to the surface of the Earth, only in this case, it happens on the surface of the ocean floor -- causing the oil-like ooze to solidify.
As NOAA explains it, the tarry ooze expelled from asphalt volcanoes is like what one finds in oil refineries, "the gooey residue that remains after extraction of gasoline." On dry land, this residue is often mixed with sand and a less viscous oil, then its heated and used pave roads -- voilà, asphalt.
But when the same gooey residue -- the more volatile components of the deep Earth oil having been evaporated -- is squeezed through a hole in the ocean floor and mixed with cold salt water, the result is a giant asphalt flower.
In addition to asphalt flowers, NOOA's D2 also spotted corals, barnacles, anemones and fish. Bacteria along the ocean floor has found a way to use the oil as food, enabling "a sulfur-based food chain."