The Nasa Haughton-Mars Project.

The NASA Haughton-Mars Project.

A thousand miles or so from the Earth's North pole lies our planet's largest uninhabited island, Devon Island. Devon Island is the largest uninhabited island on Earth, with a surface area of approximately 66,800 km2. Its geology presents two major provinces: a thick (presently ~ 1.3 km) subhorizontal sequence of Paleozoic (Cambrian to Devonian) marine sedimentary rocks dominated by carbonates (dolomite and limestone) forming part of the Arctic Platform; and a Precambrian crystalline (gneissic) basement lying unconformably under the stack of marine sediments, forming part of the Canadian Shield. The Paleozoic sediments present a gentle dip of approximately 4° towards the west. The flat-topped plateau characterizing much of Devon Island's surface is an old erosional surface (peneplain) exposing sediments of increasing age towards the east. Devon Island is home to one of the highest-latitude impact structures known on Earth, Haughton Crater. At 20 kilometers in diameter the crater formed 23 million years ago, at the beginning of the Miocene, when an asteroid or a comet collided with our planet.

Little imagination is required to believe oneself on Mars when exploring Devon Island. Many features and sites there are strikingly reminiscent of the Martian landscape, from barren rocky blockfields to intricate valley networks, from precipitous winding canyons to recent gully systems on their slopes. We come here to understand whether this resemblance is merely a coincidence or whether there are common underlying causes. Did some of the processes that shaped Devon Island also operate on Mars?

The object that struck Devon Island was perhaps 1 kilometer (0.6 mile) in diameter. Coming in at cosmic speeds, the impactor delivered a pulse of energy equivalent to 100 million kilotons of TNT. In so doing, it produced a blinding flash of light followed by a monumental air blast that flattened the surroundings, obliterating almost all life several hundred kilometers around. As the impactor itself blended into the target rocks and vanished as a superheated gas, a colossal shock wave expanded into the subsurface. Rocks were crushed, melted, vaporized, and ejected. Soon, a gaping crater 20 kilometers (12.4 miles) wide and 1.7 kilometers (1 mile) deep appeared, only to shallow out moments later as its unstable walls collapsed inwards. As the dust cleared, a smoldering hole filled with a vast pool of chunky molten carbonates appeared. Haughton Crater was born.

Early research efforts at Haughton focused on studies of the crater itself with investigations into a possible Mars analog angle remaining unexplored. I approached Chris McKay at NASA Ames Research Center to do just that. With his visionary support, I obtained in 1997 a grant from the National Research Council to visit Haughton Crater. As a result, a four-person team traveled to Devon Island in August of that year. Comprising this initial field party were James W. Rice, Jr. (at that time based at NASA Ames, now at Arizona State University), John W. Schutt (chief field guide for the U.S. Antarctic Search for Meteorites program), Aaron Zent (NASA Ames), and myself. The site proved interesting beyond our wildest dreams. Not just one, but several features were found that might serve as potential Mars analogs.

The ground-ice on Devon Island and indeed across the high Arctic represents an important repository of freshwater and, as suggested by known examples from Siberia, might even trap a biological record covering several million years. Recent neutron spectrometry data from the Mars Odyssey spacecraft provide startling possible evidence