GRAND MARAIS, Minn. - A forest fire has led to a chance discovery of debris from the impact of a meteorite 1.85 billion years ago, more than 450 miles away at Sudbury, Ontario. Geologists had scheduled a field trip in May along the Gunflint Trail in northeastern Minnesota, but most areas they wanted to explore were closed because of a wildfire that charred more than 118 square miles. Geologist Mark Jirsa of the Minnesota Geological Survey went up the trail to scout new locations and, in a spot he had never visited before, stumbled across debris now linked to the...