On June 28, 2004 the JOIDES Resolution, a 471 ft drillship, will embark from Astoria, Oregon, upon the first expedition of the Integrated Ocean Drilling Program (IODP). This eight-week voyage is the first of a series of ocean research missions designed to contribute fundamental scientific knowledge for climate change, geologic hazards, energy resources, and Earth's environment. The scientists will be returning to an area about 120 mi. (200 km) off the coast of British Columbia west of Vancouver Island to drill and collect sample cores from deep below the seafloor.
Andrew Fisher, professor of Earth sciences at the University of California, Santa Cruz, is co-chief scientist of this first IODP expedition, along with Tetsuro Urabe of the University of Tokyo. Fisher and his collaborators previously studied this area eight years ago on ODP Leg 168. In a paper published last year in Nature, the researchers reported their discovery of fluid flow between a pair of seamounts in this area that are separated by more than 30 mi. (52 km).
During the expedition an international team of scientists will investigate how fluid flows through rock formations beneath the seafloor to the eastern flank of the Juan de Fuca Ridge. The Juan de Fuca Ridge, west of the drill site, is a place where new oceanic crust is being built as two oceanic plates spread apart and fresh lava pours out of the seafloor. To the east, the Juan de Fuca Plate dives beneath the edge of the North American Plate.
According to Fisher, the amount of water that circulates through the upper oceanic crust is equivalent to the combined flows of all the rivers that pour off of the continents. Driven by slight differences in temperature and pressure within the seafloor, this hydrothermal flow is enough to recirculate all of the water in the oceans through the seafloor every few hundred thousand years, he said.
"This process affects the chemistry of the ocean, changes the properties of the crust itself, and influences the microbial communities that live below the seafloor," Fisher said. "We know it's important, but we really don't understand much about how it works."
The researchers will be drilling holes deep into the seafloor and capping the holes with elaborate structures called CORKs that will enable scientists to monitor processes beneath the seafloor and conduct experiments. The researchers plan to put in four observatories this summer.
The CORKs stand about two stories high on the ocean floor and cap boreholes that extend hundreds of meters through the seafloor sediments and into the basalt of the upper oceanic crust. These observatories allow measurement of temperature, pressure, fluid chemistry, and microbiology from different depths in the borehole. The observatories will enable researchers to conduct a cross-hole test for fluid flow.
The IODP is an international scientific research endeavor funded by the US National Science Foundation; the Ministry of Education, Culture, Sports, Science, and Technology of Japan; and the European Consortium for Ocean Research Drilling.
6/21/04
