Exploring an Unknown Arctic Seabottom (No Ice Included)
|The seismic research vessel Marcus G. Langseth prepares to leave Dutch Harbor, Alaska (Bernard Coakley, U of Alaska)
Readers can follow a New York Times blog from the arctic as the U.S. flagship vessel for charting geology under the seabed sails the Chukchi Sea, north of Alaska and Siberia. By sending sound pulses to the seabed and reading the echoes, scientists conducting the Chukchi Edges project aboard the Marcus G. Langseth hope to understand the structure and history of the continental shelves running underwater off Asia and North America, and the Chukchi Borderland, an adjoining region of dramatic deep-sea plateaus and ridges some 800 miles from the North Pole.
The Langseth is run by Columbia University’s Lamont-Doherty Earth Observatory for the U.S. National Science Foundation. Blogger and chief scientist for this cruise is Lamont alumnus and onetime researcher Bernard Coakley, now a leading force in arctic marine geology based at the University of Alaska, Fairbanks. Since the 1990s, Coakley has sailed many times on icebreakers, as well as Navy submarines traversing under the ice. (As he notes in his blog, he was invited onto one early voyage by Lamont geologist Marcus Langseth, for whom the vessel is named.)
Images produced by the cruise should help clarify scientists’ understanding of how the depths of the Arctic Ocean came to be–and maybe more contemporary matters. Conventional models have what are now Asia and North America opening up like a pair of scissors millions of years ago to form the abyss, but many details remain unknown. Beyond that, the five nations now bordering the Arctic Ocean–Russia, the United States, Canada, Denmark (via Greenland) and Norway–are all furiously working to document possible offshore territorial claims, and marine geology may play a key role in some cases.
The work is heating up as more areas become ice free, exposing vast potential mineral and gas deposits, and filing deadlines loom under the international Law of the Sea agreement. Information about the evolution of underwater terrains, and whether they are or were at one time attached to certain landmasses, may help determine whether some nations can claim areas beyond the conventional 200 nautical miles off their coasts. The purpose of the cruise is not political, says Coakley; in any case, the Chukchi Borderlands, likely to fall within U.S. jurisdiction, are probably not prospective for minerals. But icebreakers from the various nations have been plying many other places this season in pursuit of data.
One thing for sure: the Langseth is neither an icebreaker, nor even reinforced against ice. This is its first arctic cruise–made possible by the fact that the Chukchi, in the past too frozen for navigation most of the year, has opened dramatically. Melting in recent years is thought due to global warming and shorter-term natural weather variations–a combination that this month brought arctic ice to its lowest September level ever recorded. The crew will have to watch for ice and may turn back if it gets heavy–but the fact that they dare sail here at all is a testament to the extent to which the arctic, and the world, are changing.