Huge crater discovered in Greenland – here’s how the impact may have wiped out the mammoths
Scientists have discovered a 31km wide impact crater beneath the Hiawatha glacier in Greenland. The discovery, published in Science Advances, was made using airborne radar surveys which unveiled a circular bedrock depression beneath the ice. The presence of quartz and other grains and features on the ground helped the team confirm the finding – these showed signs of having been subjected to large shock pressures.
Analysis of the grains also shows that the impact was most likely made by an iron meteorite more than 1km wide. It would have occurred during the Pleistocene, between about 12,000 and 3m years ago. This is by no means the only large impact crater on Earth, and research shows just how much such features can teach us about the history of our planet – including the evolution of life. So how could the Greenland impact have changed our planet?
Many of the oldest impacts from space occurred on our planet’s most ancient crusts and in the centre of its large, continental tectonic plates. Unfortunately, this crust is continually renewed – older rocks are destroyed by weathering processes and the remains are recycled into new rocks. This process destroys evidence of early impacts from large bodies. Also, many impact craters (often initially mistaken for extinct volcanic craters) have formed circular lakes, meaning that many features have been lost due to water erosion.