Manicouagan Reservoir
Template:Short description Template:Use Canadian English Template:Use dmy dates Template:Infobox body of water
Manicouagan Reservoir (also Lake Manicouagan Template:IPAc-en; {{#invoke:IPA|main}}) is an annular lake in central Quebec, Canada, covering an area of Template:Convert. The lake island in its centre is known as René-Levasseur Island, and its highest point is Mount Babel. The structure was created 214 (±1) million years ago, in the Late Triassic, by the impact of a meteorite Template:Convert in diameter. The lake and island are clearly seen from space and are sometimes called the "eye of Quebec". The lake has a volume of Template:Convert.<ref name=HQ/><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
GeographyEdit
The reservoir is located in Manicouagan Regional County Municipality in the Côte-Nord region of Quebec, Canada,<ref name="EarthImpactDB">Template:Cite Earth Impact DB</ref> about Template:Convert north of the city of Baie-Comeau, although its northernmost part is located in Caniapiscau Regional County Municipality. Quebec Route 389 passes the eastern shore of the lake.
The crater is a multiple-ring structure about Template:Convert across, with the reservoir at its Template:Convert diameter inner ring being its most prominent feature. It surrounds an inner island plateau called René-Levasseur Island and Mount Babel is the highest peak of the island, at Template:Convert above sea level and Template:Convert above the reservoir level. The Louis-Babel Ecological Reserve makes up the central part of the island. The large bay on the eastern shore of the island is named Memory Bay.
Impact structureEdit
Template:Infobox terrestrial impact site Manicouagan Reservoir lies within the remnant of an ancient, deeply eroded impact crater (Impact structure). The crater was formed following the impact of an asteroid with a diameter of Template:Convert, which excavated a crater originally about Template:Convert wide, although erosion and deposition of sediments have since reduced the visible diameter to about Template:Convert. It is the Earth's sixth-largest confirmed impact structure according to rim-to-rim diameter.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> Mount Babel is interpreted as the central peak of the crater, formed by post-impact uplift.
1992 radiometric dating has estimated that impact melt within the impact structure has an age of 214 ± 1 million years. A later estimate found an age of 215.4 ± 0.16 Ma.<ref>Template:Cite journal</ref> As this is more than 12 million years before the end of the Triassic, the impact that produced the crater cannot have been the cause of the Triassic–Jurassic extinction event.<ref>Template:Cite journal</ref><ref>Ramezani, J., S. A. Bowring, M. S. Pringle, F. D. Winslow, III, and E. T. Rasbury (2005). "The Manicouagan impact melt rock: a proposed standard for intercalibration of U-Pb and 40Ar/39Ar isotopic systems". 15th V.M. Goldsmidt Conference Abstract Volume, p. A321.</ref>
Multiple impact event claimsEdit
It was suggested that the Manicouagan crater may have been part of a multiple impact event, similar to the well-observed string of impacts of Comet Shoemaker–Levy 9 on Jupiter in 1994.<ref>Template:Cite news</ref> The theory suggests this event also formed the Rochechouart impact structure in France, the Saint Martin crater in Manitoba, the Obolon' crater in Ukraine, and the Red Wing crater in North Dakota;<ref name="Spray-1998">Template:Cite journal</ref> however, more recent work has found that the craters formed many millions of years apart, with the Saint Martin crater dating to 227.8 ± 1.1 Ma,<ref>Template:Cite journal</ref> while the Rochechouart structure formed 206.92 ± 0.20/0.32 Ma.<ref>Template:Cite journal</ref>
Hydroelectric projectEdit
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The Manicouagan Reservoir as it presently exists was created in the 1960s, by flooding the earlier Lake Mushalagan (Mouchalagan) to the west of the central plateau and then-smaller Manicouagan to the east, by construction of the Daniel-Johnson dam.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The works were part of the enormous Manicouagan or Manic series of hydroelectric projects undertaken by Hydro-Québec, the provincial electrical utility. The complex of dams is also called the Manic-Outardes Project because the rivers involved are the Manicouagan and the Outardes.
The reservoir acts as a giant headpond for the Manicouagan River, feeding the Jean-Lesage generating station (Manic-2), René-Lévesque generating station (Manic-3), and Daniel-Johnson Dam (Manic-5) generating stations downstream. In the peak period of the winter cold, the lake surface is usually lower, since the turbines run all the time at peak load to meet the huge electrical heating needs of the province. The surface of the lake also experiences low levels in the extreme periods of heat in New England during the summer, since in that period Hydro-Québec sells electrical energy to the joint New England grid and individual utilities in the United States.
See alsoEdit
- Manicouagan Uapishka Biosphere Reserve
- List of impact structures on Earth
- Wembo-Nyama ring structure
ReferencesEdit
External linksEdit
- Manicouagan at Earth Impact Database
- Manicouagan Impact Structure at Crater Explorer
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