Saint Martin impact structure

Saint Martin is an impact structure in Manitoba, Canada.^[1] It is located in the northern part of the Rural Municipality of Grahamdale, northwest of Lake St. Martin.

Saint Martin impact structure
Location of the impact structure in Canada
Impact crater/structure
Confidence	Confirmed
Diameter	40 km (25 mi)
Age	227.8 ± 1.1 Ma Carnian
Exposed	No
Drilled	Yes
Location
Coordinates	51°47′N 98°32′W
Country	Canada
Province	Manitoba
Municipality	Grahamdale

The impact structure is 40 km (25 mi) in diameter and its age was determined to be 227.8 ± 1.1 million years^[2] (Carnian stage of the Triassic) using the argon-argon dating technique. The crater is well preserved but poorly exposed at the surface as the whole region is covered by glacial drift.

Hypothetical multiple impact event

Main article: Manicouagan impact structure § Hypothetical multiple impact event

It had previously been suggested by Geophysicist David Rowley of the University of Chicago, working with John Spray of the University of New Brunswick and Simon Kelley of the Open University, that the Saint Martin structure may have been part of a hypothetical multiple impact event which also formed the Manicouagan impact structure in northern Quebec, Rochechouart impact structure in France, Obolon' crater in Ukraine, and Red Wing crater in North Dakota.^[3] All of the impact structures had previously been known and studied, but their paleoalignment had never before been demonstrated. Rowley has said that the chance that these structures could be aligned like this due to chance are nearly zero.^[4]