Researchers funded by the National Science Foundation (NSF) are sailing on the maiden scientific voyage of the U.S. Coast Guard's newest icebreaker to study one of the world's slowest growing oceanic ridges, with an eye to understanding how the Earth's crust forms.
The USCGC Healy, which is outfitted as a scientific research vessel, will carry out the Arctic Mid-Ocean Ridge Expedition (AMORE) from late July until early October. The Healy will sail with the German research vessel Polarstern to sample and study the Gakkel Ridge, a little-known geologic feature in the Arctic Ocean.
The Gakkel Ridge occupies a unique and important place within the global system of ocean ridges for several reasons. It is the deepest and slowest spreading ridge. It also is the only spot on the globe from which the polar mantle, under the ocean, can be sampled directly.
Healy will use dredges to bring up rock samples from the ridge. To date only two small samples have ever been recovered from the 5000-meter (3.1- mile) deep ridge.
"We will recover volcanic rocks that we will analyze chemically to learn more about mid-oceanic ridges in general, including how the planet's oceanic crust is created by seafloor spreading," said principal investigator Peter J. Michael, professor of geosciences at the University of Tulsa.
Along the mid-ocean ridge, volcanic material is added to crustal plates that move away from each other. The Gakkel Ridge is special because its seafloor-spreading rate is about one centimeter (.39 inches) per year -- the slowest on earth -- compared to other ridges that spread at up to 18 centimeters (7 inches) annually. Slow-spreading ocean ridges are a global rarity and their mechanics are not well understood.
Forming the northern end of the Atlantic Ocean ridge system, the Gakkel is one of the least-studied mid-ocean ridges. Data collected by AMORE is expected to provide a basic understanding of the makeup of Arctic Ocean crust and its influence on Arctic Ocean chemistry.
The vessels will make the 800-mile voyage from Norway to the edge of the ice cap in three days, traveling at approximately 12 knots (13.8 mph). Once in the ice, the vessels expect to average 3 knots (3.45 mph), depending on thickness of the ice that needs to be broken. The combination of the Healy and Polarstern working together will enhance safety in the ice and make for more efficient data gathering.
The permanent ice cover of the Arctic Ocean has previously hindered study of the Gakkel Ridge. AMORE used data collected by SCICEX, a joint exercise of the U.S. Navy's Office of Naval Research and NSF in which submarines have mapped large areas of the bottom of the Arctic Ocean, to develop its sampling program, according to AMORE researcher Henry Dick of the Woods Hole Oceanographic Institution (WHOI).
"Scientists previously thought there was little volcanic activity along the Gakkel Ridge, but information from a 1999 submarine cruise indicates there may be an isolated, very large megavolcano at the eastern end of the ridge filling up the crack," he said.
AMORE also will host Michele Adams, a 7th grade science teacher at Musselman Middle School in West Virginia. Adams is a participant in NSF's Teachers Experiencing the Arctic and Antarctic Program (TEA).
Other U.S. institutions involved in AMORE include the Lamont Doherty Earth Observatory at Columbia University and Oregon State University. German institutions include Alfred Wegener Institute in Bremerhaven, Max-Planck Institute in Mainz and the University of Bremen.
To read more about NSF's support of scientific logistics in the Polar Regions, see http://www.nsf.gov/od/lpa/news/media/01/fslogistics.htm
The Woods Hole Oceanographic Institute will post bulletins from the Healy at sea at http://www.arcticvolcanoes.com
To follow teacher Michele Adams' experiences, see http://tea.rice.edu/tea_adamsfrontpage.html
For more information about the Healy, see http://www.uscg.mil/pacarea/Healy/
For more information about SCICEX, see http://www.ldeo.columbia.edu/SCICEX/
NSF is an independent federal agency which supports fundamental research and education across all fields of science and engineering, with an annual budget of about $4.5 billion. NSF funds reach all 50 states, through grants to about 1,800 universities and institutions nationwide. Each year, NSF receives about 30,000 competitive requests for funding, and makes about 10,000 new funding awards.
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