Deep-Sea Asphalt Formations: Tar Lilies Discovery

An intriguing sonar signal from the depths of the Gulf of Mexico set the discovery in motion. During a research expedition by the United States' National Oceanic and Atmospheric Administration (NOAA), scientists identified an unusual object on the seafloor approximately 1,900 meters below the surface. Its shape and size suggested the possibility of a sunken vessel, prompting researchers to deploy the Deep Discoverer underwater robot for closer examination. When the robot reached its destination, however, the search for a shipwreck led to an entirely different find. Instead of maritime debris, large structures stood on the seabed resembling flowers growing from the earth.

These formations earned the nickname "Tar Lilies." They are actually natural eruptions of asphalt that solidified on the ocean floor. Dense petroleum and hydrocarbon materials are forced under pressure through cracks in the seabed sediment. When this material reaches the extremely cold deep waters, it cools and hardens rapidly. During the cooling and contraction process, folds and cracks form, and in certain cases these arrange themselves into petal-like shapes surrounding a central point, creating the appearance of a giant flower.

Researchers documented two such formations that day. NOAA notes these were the first known examples of activity termed "asphalt volcanism" in this region of the Gulf of Mexico. Similar phenomena are known from other locations with hydrocarbon deposits beneath the seabed, but the unusual flower shape and the site where they were found made the discovery particularly intriguing.

Oil flowers found on the seabed (NOAA OKEANOS EXPLORER)

The biggest surprise, however, extended beyond geology. As the robot's cameras approached the "lilies," it became clear that the solid asphalt had essentially become a small island of life amid a seafloor largely covered in soft sediment. Corals, sea anemones, and other marine creatures clung to the hard asphalt surfaces and settled on them. Around the base of the structures, researchers also found organisms associated with hydrocarbon seeps, including tube worms and mats of microorganisms that use chemical processes rather than sunlight to generate energy.

The creatures inhabiting the structures also provided researchers with clues about their age. According to estimates made following the expedition, some of the formations may be decades or even centuries old. This means the asphalt seepage is not necessarily a one-time event, but part of an active and ongoing geological system transporting oil and gas from deep layers to the ocean floor.

The expedition was designed to map and document under-researched areas of the Gulf of Mexico, and the story illustrates how little is still known about vast portions of the ocean floor. Even in a region studied for years due to the oil industry, fishing, and maritime activity, it remains possible to encounter extraordinary geological structures never previously documented.

And what about the sunken ship they originally sought? Later in the expedition, actual shipwreck remains were indeed located. But it was the target that turned out to be a sonar error that led researchers to one of the voyage's most remarkable findings, "flowers" formed from natural tar in the ocean depths that over the years became a thriving habitat for marine life.