Underwater chemistry creates massive seafloor mineral deposits

Cores retrieved from a mound at the bottom of the sea where sulfide deposits are actively forming indicate that these modern-day accumulations are comparable in size with valuable ancient deposits on land. The cores also provide important new clues about how volcanic-associated massive sulfide deposits are initially formed. A multinational team of scientists brought these insights back from a fall 1994 cruise of the Ocean Drilling Program (ODP), an international partnership for geological oceanography funded principally by the U.S. National Science Foundation, and reported its work in Nature [ 377, 713 (1995)]. The results of this expedition have been "eagerly awaited," according to Randolph A. Koski, a geologist with the U.S. Geological Survey in Menlo Park, Calif. The study "provides, for the first time, a glimpse of the processes operating within such a deposit," he commented in Nature . Overcoming the engineering challenges of drilling into an active hydrothermal system, the team drilled 17 holes into the ...