背景
An impact formed the Sudbury Basin in present-day Canada around 1.85 billion years ago. The original crater was probably more than 200 kilometres across, but later tectonic deformation and erosion greatly altered its shape. Impact processes helped concentrate nickel- and copper-bearing deposits that later became important for mining. Studies of melt rocks and shock structures connect the basin to a collision from space.
资料来源： NASA — Sudbury Impact Structure