Sudbury Structure, Ontario: Some Petrographic Evidence for Origin by Meteorite Impact

Unusual deformation structures, similar to those observed in rocks from known and suspected meteorite impact craters, are observed in inclusions of basement rock in the Onaping formation at Sudbury, Ontario. These features, which include planar sets in quartz parallel to the (0001) and (10ī3) planes, suggest that the Onaping formation consists of shocked and melted material deposited immediately after a meteorite impact which formed the Sudbury basin.