Haughton impact crater

Haughton impact crater is located on Devon Island, Nunavut in far northern Canada. It is about 23 km (14 mi) in diameter and formed about 39 million years ago during the late Eocene. The impacting object is estimated to have been approximately 2 km (1.2 mi) in diameter. Devon Island itself is composed of Paleozoic shale and siltstone overlying gneissic bedrock. When the crater formed, the shale and siltstone were peeled back to expose the basement; material from as deep as 1,700 m (5,600 ft) has been identified.

• http://en.wikipedia.org/wiki/Haughton impact crater