Rochechouart crater - AbsoluteAstronomy.com

Rochechouart is an impact crater

Impact crater

In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...

in France.

The crater diameter

Diameter

In geometry, a diameter of a circle is any straight line segment that passes through the center of the circle and whose endpoints are on the circle. The diameters are the longest chords of the circle...

is still under study but is expected to be about 21 km (13 mi). Its most recent age estimate is 201 ±2 million years ago, placing it close to Triassic

Triassic

The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...

-Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

boundary. Since then the crater has been deeply eroded, and no trace of its original surface morphology is visible. The crater appears to be too small to account for the Triassic–Jurassic extinction event.

Its centre is tentatively located at the hamlet of La Judie 4 km (2.5 mi) west of Rochechouart

Rochechouart

Rochechouart is a commune in the Haute-Vienne department in the Limousin region in west-central France. It is a sub-prefecture of the department....

, in the Haute-Vienne

Haute-Vienne

Haute-Vienne is a French department named after the Vienne River. It is one of three departments that together constitute the French region of Limousin.The chief and largest city is Limoges...

département; its surface extent includes the communes and villages of Rochechouart, Chaillac

Chaillac

Chaillac is a commune in the Indre department in central France.-See also:*Communes of the Indre department* Rochechouart crater* Saint-Benoît-du-Sault* Château de Brosse-References:*...

, Étagnac

Étagnac

Étagnac is a commune in the Charente department in southwestern France.-Population:-References:*...

, Pressignac

Pressignac

Pressignac is a commune in the Charente department in southwestern France.-Population:-References:*...

, Lésignac-Durand

Lésignac-Durand

Lésignac-Durand is a commune in the Charente department in the Poitou-Charentes region in southwestern France.-Georgraphy:The commune is found within the Rochechouart meteorite crater.-Population:-Personalities:...

, Saint-Quentin-sur-Charente

Saint-Quentin-sur-Charente

Saint-Quentin-sur-Charente is a commune in the Charente department in southwestern France.-Population:-References:*...

, Chéronnac

Chéronnac

Chéronnac is a commune in the Haute-Vienne department in the Limousin region in western France.-Geography:At Chéronnac is the source of Charente River.Inhabitants are known as Chéronnacais.-References:*...

, Chassenon and Chabanais

Chabanais

Chabanais is a commune in the Charente department in southwestern France.-Geography:The Vienne River passes through Chabanais. The village is located in the Rochechouart crater, an ancient asteroid impact crater that eroded away and is not visible anymore....

.

The remnants of this astrobleme have been a major subject of debate among geologists since their discovery in the early 19th century. The explanation was only given in 1969 by the French geologist François Kraut, who definitely proved the impact origin of the breccia

Breccia

Breccia is a rock composed of broken fragments of minerals or rock cemented together by a fine-grained matrix, that can be either similar to or different from the composition of the fragments....

s.

The Rochechouart impact crater was the first crater the nature of which was proven by the determination of the impact effects on the rocks, without any circular topographic features being visible.

Hypothetical multiple impact event

It has been suggested by Geophysicist David Rowley of the University of Chicago

University of Chicago

The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...

, working with John Spray of the University of New Brunswick

University of New Brunswick

The University of New Brunswick is a Canadian university located in the province of New Brunswick. UNB is the oldest English language university in Canada and among the first public universities in North America. The university has two main campuses: the original campus founded in 1785 in...

and Simon Kelley of the Open University

Open University

The Open University is a distance learning and research university founded by Royal Charter in the United Kingdom...

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

Manicouagan crater

The Manicouagan Crater is one of the oldest known impact craters and is located primarily in Manicouagan Regional County Municipality in the Côte-Nord region of Québec, Canada, about north of the city of Baie-Comeau. Its northernmost part is located in Caniapiscau Regional County Municipality...

in northern Quebec

Quebec

Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....

, Saint Martin crater

Saint Martin crater

Saint Martin is an impact crater in Manitoba, Canada.It is in diameter and its age is estimated at 220 ± 32 million years . The crater is not exposed at the surface.-Hypothetical multiple impact event:...

in Manitoba

Manitoba

Manitoba is a Canadian prairie province with an area of . The province has over 110,000 lakes and has a largely continental climate because of its flat topography. Agriculture, mostly concentrated in the fertile southern and western parts of the province, is vital to the province's economy; other...

, Obolon' crater

Obolon' crater

Obolon' crater is a diameter buried meteorite impact crater situated about southeast of Kiev in Ukraine .The site has been drilled, which revealed the presence of shocked minerals and impact melt rock; the high chlorine content of the latter suggesting that the area was covered by shallow sea at...

in Ukraine

Ukraine

Ukraine is a country in Eastern Europe. It has an area of 603,628 km², making it the second largest contiguous country on the European continent, after Russia...

, and Red Wing crater

Red Wing crater

Red Wing or Red Wing Creek structure is a meteor crater located inMcKenzie County, North Dakota, about southwest of Watford City, North Dakota, United States....

in North Dakota

North Dakota

North Dakota is a state located in the Midwestern region of the United States of America, along the Canadian border. The state is bordered by Canada to the north, Minnesota to the east, South Dakota to the south and Montana to the west. North Dakota is the 19th-largest state by area in the U.S....

. 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.

External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.