Sub to seek signs of ancient humans off Galveston Far below the Gulf's surface, experts in sub will seek signs of early man in North America

Lt. John Roussakies, executive officer of the U.S. Navy's research submarine the NR-1, departs the sub. Lt. John Roussakies, executive officer of the U.S. Navy's research submarine the NR-1, departs the sub. Photo: Steve Ueckert, Chronicle Photo: Steve Ueckert, Chronicle Image 1 of / 1 Caption Close Sub to seek signs of ancient humans off Galveston 1 / 1 Back to Gallery

GALVESTON — A U.S. Navy submarine that can roll on wheels across the ocean floor will leave Pier 40 today on a weeklong expedition to search the deep for evidence of ancient human habitation.

The Navy's only nuclear-power research vessel, the NR-1, will carry scientists looking for signs of early humans who may have lived on a coast that 19,000 years ago extended 100 miles farther into the Gulf of Mexico than it does today.

If scientists on the expedition, dubbed "Secrets of the Gulf," find evidence that humans roamed those ancient shores, it would push back the earliest known date of prehistoric human habitation in North America by about 8,000-10,000 years, said Dwight Coleman, the expedition's chief scientist.

Scientists also will examine the effects of rising sea levels following the last Ice Age, which could offer insights into how to deal with the expected rise in sea levels caused by warming temperatures.

Robert Ballard, the scientist who discovered the wreckage of the Titanic and the German battleship Bismarck, will direct the search from a telecommunications center lined with 50-inch plasma monitors at the Institute for Exploration at the Mystic Aquarium in Connecticut.

Ballard, along with scientists at five other U.S. locations, will monitor instruments giving temperature, depth, water salinity and other data along with images from the submarine broadcast via satellite in real time, and be able to give directions to the two scientists on board.

Ballard will have 16 communications lines allowing him to speak directly with scientists on board the submarine and its support ship, the 238-foot Carolyn Chouest, crammed with scientific equipment and high-tech communications gear.

The 24 scientists on board the vessels will use sonar to map an ancient coastline, now about 390 feet below the surface, that would have roughly followed the present coral reefs that make up the Flower Garden Banks National Marine Sanctuary, overseen by the National Oceanic & Atmospheric Administration.

"Nobody's ever found anything from 20,000 years ago offshore, but that's because nobody has ever looked," said anthropologist David Robinson, a member of the expedition from the University of Connecticut.

Robinson said that even if the expedition failed to find evidence of human habitation, it would lay the groundwork for doing so by determining the location of the ancient coast and the prehistoric beds of Texas rivers like the Sabine and Trinity.

Ballard said the best place for human settlement is where a river meets the sea, places covered by the sea after the last ice age and until now in waters too deep to explore.

The Flower Garden Banks are coral reefs lush with wildlife on top of salt domes that have pushed up from the sea beds. The salt would have been above water and sought by humans and animals alike 19,000 years ago, making it a prime location for hunting, Ballard said.

If they get lucky, the scientists might spot a trash heap used by ancient humans or the remains of a salt mine, he said. The expedition also will help map the undersea territory of the United States, he said.

"We have better maps of Mars than we do of submerged America," said Ballard, who noted that 50 percent of U.S. territory is underwater.

Ballard said the expedition also was a test run for technology that would find its fullest expression in a NOAA research vessel being outfitted with the latest technology in a Seattle dry dock.

The Okeanos Explorer will explore the oceans 10 months a year, beaming a constant stream of information to the Inner Space Center, a command center under construction at the Institute for Exploration in Kingston, R.I.

The Inner Space Center will be to undersea exploration what the NASA Space Center in Houston is to outer space exploration, Ballard said.

"Instead of, 'Houston, we've got a problem,' it will be, 'Kingston, we've got a problem,' " he said.

The expedition cost of about $300,000 is shared by NOAA, the National Marine Sanctuary Foundation, the Institute for Exploration, Immersion Presents and the University of Rhode Island, Ballard said.

Two scientists, a geologist and an archaeologist, will share the cramped quarters with the 13-member crew.

Researchers also will take sediment samples, explore brine lakes that seep from the salt domes and view mud volcanoes formed by escaping methane gas.

harvey.rice@chron.com