Arctic mounds have gassy past

Monterey Bay Aquarium Research Institute (MBARI) scientists working in the Arctic Ocean unraveled the geological origin of many mysterious mounds, called “pingos”, off Canada’s north coast. Pingos are small, dome-shaped, ice-cored hills about 40m tall, found along the coast of the Tuktoyaktuk Peninsula. Earlier studies claimed these features were formed on land, and then submerged when sea level rose following the end of the last ice age, over 10,000 years ago. Apparently, the reverse may be true.