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CORVALLIS, Ore. - Oregon State University oceanographer Marta Torres left this week to lead an international scientific team on a 14-day cruise aboard the research vessel New Horizon to gather data on the fate of mineral deposits formed at the ocean floor 100 kilometers south of San Diego, Calif.

About a decade ago, Torres discovered deposits of barite off the shore of Peru. More recently, she led an expedition using the Alvin - a small deep-sea submarine - to investigate an offshore fault in the San Clemente Basin. Here, scientists found what they call a "cold seep," an area where methane- and barium-enriched fluids seep from the sediment and cause barite columns to form on the ocean floor.

Some of these barite pillars are as tall as 10 meters and the mineral dregs are growing at the rate of about 1 centimeter per year, creating large deposits of barite along the seafloor.

Scientists now know that the deposits forming today are analogous to ancient barite formations currently being mined in Nevada, Arkansas, and China. Barite is used in various industries for gasoline production, oil-well drilling, as an additive in cement, rubber, and urethane foam, in automobile paint primer and "leaded" glass, and as the raw material for barium chemicals.

Barium has become part of the brake and clutch pads in vehicles and is used in television sets and computer monitors as a radiation barrier. None of it is recycled or stockpiled. In the United States, estimated resources of barite are at 150 million tons, while the U.S. consumption was 1.67 million tons in 2002, according to the U.S. Geological Survey.

In addition to its economic potential, geochemists use barium in the ocean to study water circulation and infer changes that have occurred in the Earth's climate, Torres pointed out.

"Barite in cold seeps is isotropically different from barite formed at the ocean surface so it is important to quantify the contribution of these cold-seep deposits to the sediment record to accurately reconstruct the changes in ocean currents and productivity over time," Torres said.

Because the San Clemente Basin is geographically semi-enclosed, scientists have the opportunity to evaluate how much these cold seeps are contributing to the local geochemical cycles. This information can then be used to estimate the relative contribution of cold-seep systems to the global supply of barium and to map its chemical signature in marine sediments.