The Healy will use her sound imaging instruments to map the scarcely-studied seabed of the Canadian Basin, while the Louis St. Lauren will collect seismic data to determine the thickness of sediment on the ocean floor.

Scientifically, the mission is to produce plenty of new data on the uncharted region. As Captain Steve Barnum of the US National Oceanic and Atmospheric Administration put it, “We have better maps of the moon than we do of our own ocean floor.”

The expedition has a more pragmatic goal as well. The data collected by American and Canadian researchers over the planned three years of Arctic expeditions is to lay the foundation for the two countries’ bids for the continental shelf extending north from the North American continent. In accordance with the UN Convention on the Law of the Sea, a country may claim exclusive rights on seabed mining if it proves to be a continuation of its territory. A similar claim for another part of the Arctic, the Lomonosov Ridge, is being prepared now by Russia, which held a seabed survey of its own in 2007.

Some 13% of the world’s undiscovered oil reserves and 30% of undiscovered natural gas reserves are estimated to lie under the Arctic seabed. With climate change making the riches more available for drilling, the polar-bordering nations of the US, Canada, Russia, Denmark and Norway are preparing for an Arctic race.

The joint US-Canadian expedition will not focus on territorial disputes, neither with other possible claimants nor between them.

“If there turn out to be overlaps – and it’s really too premature to start speculating on that, because we are still collecting data – but if they do, we will sort them out [in accordance] with international law by negotiation or arbitration,” said Allison Saunders, deputy director of the continental shelf division at the Canadian Department of Foreign Affairs.

The United States and Canada already have a standing border dispute in the north. They have failed to agree on how to draw the nautical borderline, with Ottawa advocating a border going straight north from the Alaska-Yukon land border, while Washington prefers the borderline perpendicular to the coastline. Both sides admit their claims on the continental shelf may conflict with each other.

Meanwhile, the US is not even legally able to file its claim on the Arctic, because it failed to ratify the Law of the Sea Treaty, being the only non-participant among major seafaring nations. While the Obama administration favors accession, there are many critics of the Convention too.

“President Obama is strongly in favor of the United States becoming a party to the Law of the Sea Convention,” said Margaret Hayes, director of the State Department’s Office of Ocean and Polar Affairs. “We have been in touch with the Senate Foreign Relations Committee. There is discussion going on as to the exact timing of when they might have a hearing and when they might proceed to have the full Senate consider accession.”

She added that she hoped for the issue to be resolved this year.