Nastapoka arc

The Nastapoka arc is a dramatic curved coastline on southeastern Hudson Bay in Quebec, sweeping from the Hopewell Islands toward Long Island near James Bay and standing out as one of northern Canada’s most unusual landforms. Its near-circular shape led some researchers to propose that it marked an ancient meteorite impact, but a 1972 field investigation found none of the expected impact evidence. Supported by modelling and regional geology, the leading explanation is that the arc formed as an arcuate tectonic boundary through lithospheric flexure during the Trans-Hudson orogeny about 2.0 to 1.8 billion years ago. Even so, some geologists still allow that an older impact structure may have been altered and concealed by later deformation.

Nunavut · Canada