Scientists using an underwater robot to explore three shipwrecks in the Gulf of Mexico off the coast of Galveston, Texas, have found what looks like a solidified eruption from a deep-sea volcano.

A team of researchers working at a command center at Texas A&M Galveston saw something that looked like a fourth shipwreck, said a report by the Houston Chronicle, but as the robot got closer, it became evident the spotted object was actually natural, the product of an eruption of tar from under the ocean floor that solidified when it hit the frigid water and formed what looks like a giant flower with black petals.

The volcanoes determined to have produced the mysterious floral-like forms measure about 20 feet in diameter and 10 feet at their highest points. They are the first such volcanoes found in the area and hint at more sea floor discoveries to come.

"To use a cliché, we know more about the moon than we know about the deep oceans," said Gilbert Rowe, a regent's professor in marine biology at the university. "The more we look, the more weird features we find, and each of these features is a separate habitat for the creatures that live there."

Thomas Heathman, a marine biology student working on the project, told a news crew from local KHOU-TV that he and his fellow researchers had never seen anything like the giant tar blooms in the northern Gulf of Mexico.

The shipwrecks -- all found around the same time in early 2011 by Shell workers conducting an oil and gas survey for a proposed pipeline in the company's Monterrey development tract -- are located in about 4,300 feet of water and within an estimated five miles of each other, which is approximately 150 to 170 miles away from Galveston, researchers told the Chronicle.

In July 2013, the exploration ship Nautilus recovered about 60 artifacts from one of the sunken ships -- among which were four to six different styles of firearms, porcelain plates, a leather shoe sole, bottles, cups and a cantaro, a clay pot used as a musical instrument. Earlier this month, researchers spotted an old clock in the debris of one of the wrecks.