Saint Martin is an

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact crater ...

Manitoba , image_map = Manitoba in Canada 2.svg , map_alt = Map showing Manitoba's location in the centre of Southern Canada , Label_map = yes , coordinates = , capital = Winn ...

, Canada. It is located in the northern part of the

Rural Municipality of Grahamdale Grahamdale is a rural municipality in the province of Manitoba in Western Canada. It lies in the Interlake Region. It was incorporated as a Local Government District (LGD) on 1 January 1945, and became a Rural Municipality in 1997. The municipali ...

, northwest of Lake St. Martin. The crater is in diameter and its age was determined to be 227.8 ± 1.1 million years (

Carnian The Carnian (less commonly, Karnian) is the lowermost stage (stratigraphy), stage of the Upper Triassic series (stratigraphy), Series (or earliest age (geology), age of the Late Triassic Epoch (reference date), Epoch). It lasted from 237 to 227 m ...

stage of the

Triassic The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...

) 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

It had previously been suggested by Geophysicist David Rowley of the

University of Chicago The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...

, working with John Spray of the

University of New Brunswick The University of New Brunswick (UNB) is a public university with two primary campuses in Fredericton and Saint John, New Brunswick. It is the oldest English-language university in Canada, and among the oldest public universities in North Ameri ...

and Simon Kelley of the

Open University The Open University (OU) is a British public research university and the largest university in the United Kingdom by number of students. The majority of the OU's undergraduate students are based in the United Kingdom and principally study off- ...

, that the Saint Martin crater may have been part of a hypothetical multiple impact event which also formed the

Manicouagan impact structure Manicouagan Reservoir (also Lake Manicouagan) is an annular lake in central Quebec, Canada, covering an area of . The lake island in its centre is known as René-Levasseur Island, and its highest point is Mount Babel. The structure was created ...

in northern

Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...

, Rochechouart impact structure in France, Obolon' crater in

Ukraine Ukraine ( uk, Україна, Ukraïna, ) is a country in Eastern Europe. It is the second-largest European country after Russia, which it borders to the east and northeast. Ukraine covers approximately . Prior to the ongoing Russian inv ...

, and Red Wing crater in

North Dakota North Dakota () is a U.S. state in the Upper Midwest, named after the indigenous Dakota Sioux. North Dakota is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minnesota to the east, So ...

.Spray, J.G., Kelley, S.P. and Rowley, D.B. (1998). "Evidence for a late Triassic multiple impact event on Earth". ''

Nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...

'', v. 392, pp. 171-173
Abstract
/ref> All of the craters had previously been known and studied, but their paleoalignment had never before been demonstrated. Rowley has said that the chance that these craters could be aligned like this due to chance are nearly zero.

References

External links

Aerial exploration of the St. Martin structure
{{Impact cratering on Earth Impact craters of Manitoba Triassic impact craters Triassic Canada