NEW CRATER-MAPPING TECHNIQUES COULD CHANGE HOW ASTRONAUTS PREPARE FOR THE MOON AND MARS
TTHE POLAR-DESERT environment of the High Arctic is ideal for studying ancient landforms, because unlike other places, there is no soil and little vegetation to cover them up. In 2010, scientists made a major discovery on the Prince Albert Peninsula, on Victoria Island near the Nunavut-northwest Territories border: a massive, previously unknown meteorite i mpact crater. Geologist Gordon Osinski of Western University in London, Ont., has been exploring this “Tunnunik impact crater” since 2012, probing its rocks for what they can reveal about Earth and other planets. When a large meteorite crashes to Earth, it creates deep cracks in the ground, allowing water to circulate through rocks in the crust that have been heated by the impact. Forced back to the surface by heat and pressure, the water emerges as hot springs. “Hot springs can be havens for microbial life in an otherwise harsh environment,” says Osinski. “They are where we think life on Earth may have originated — and where life may have got going on Mars too.” The first order of business, says Osinski, was geological mapping and sampling to answer essential questions about the crater’s size, when it formed and so on. “We use satellite data to steer us to potentially interesting sites, especially areas where we think there may once have been hot springs, called ‘fossil hot springs’ because they were only active for about 100,000 years,” he says. The researchers then fly in, explore and collect rock samples for the lab. The cataclysmic force of a large meteorite impact, such as the one that formed the Tunnunik crater more than 100 million years ago, leaves behind telltale features called “shattercones,” which geologists use to estimate a crater’s diameter. Because these are easily visible in the polar desert, Osinski’s team was able to assemble the most detailed shattercone map ever made. “We showed that Tunnunik is 28 kilometres in diameter,” he says, “and that’s a big crater. Also, we developed a formula that we used to improve the diameter estimates of quite a few other craters around the world.” This research, says Osinski, helps us understand the geological histories of places such as the moon, Mars and Mercury, which are dominated by meteorite impact craters. And his work has a direct connection with space exploration: Canadian astronaut Jeremy Hansen joined the crater expeditions to learn about geology. “But,” says Osinski, “also to experience an expedition to a remote environment and learn how we explore somewhere we’ve never been before. His time at the Tunnunik impact crater will benefit future Canadian astronauts who go to the moon, Mars or some other object in the solar system.”
Geologist Gordon Osinski’s research team explores the huge Tunnunik impact crater on Victoria Island, N.W.T., collecting samples to help map the ancient landform’s true extent.