| Pingualuit Crater | |
|---|---|
| New Quebec Crater Chubb Crater | |
 Satellite image of Pingualuit Crater | |
| Impact crater/structure | |
| Confidence | confirmed[1] |
| Diameter | 3.44 km (2.14 mi) |
| Depth | 400 m (1,300 ft) |
| Rise | 160 m (520 ft) |
| Age | 1.4 ± 0.1Ma |
| Exposed | yes |
| Drilled | yes |
| Bolide type | Chondrite |
| Translation | pimple[2] (Inuit) |
| Location | |
| Coordinates | 61°16′39″N73°39′36″W / 61.27750°N 73.66000°W /61.27750; -73.66000 |
| Country | Canada |
| Province | Quebec |
| District | Nord-du-Québec |
| Municipality | Kativik, Quebec |
  Pingualuit Crater Location in Quebec | |
ThePingualuit Crater (French:Cratère des Pingualuit; fromInuit "pimple"),[2] formerly called the "Chubb Crater" and later the "New Quebec Crater" (French:Cratère du Nouveau-Québec), is a relatively youngimpact crater located on theUngava Peninsula in the administrative region ofNord-du-Québec, inQuebec, Canada. It is 3.44 km (2.14 mi) in diameter, and is estimated to be 1.4 ± 0.1 million years old (Pleistocene).[1] The crater and the surrounding area are now part ofPingualuit National Park. The only species of fish in thecrater lake is theArctic char.
The crater is exposed to the surface, rising 160 m (520 ft) above the surroundingtundra, and is 400 m (1,300 ft) deep. The 267-metre-deep (876 ft) Pingualuk Lake fills the hollow, and is one of the deepest lakes in North America. The lake also holds some of the purest fresh water in the world, with a salinity level of less than 3 ppm (by comparison, the salinity level of theGreat Lakes is 500 ppm). It is one of the most transparent lakes in the world, with aSecchi disk visible more than 35 m (115 ft) deep.[3] The lake has no inlets or apparent outlets, so the water accumulates solely from rain and snow and is lost only through evaporation.
The crater was formed by ameteorite impact 1.4Ma, as estimated by40Ar/39Ar dating of impact melt rocks, making the lake one of theoldest lakes in the world. An analysis of these rocks also revealedplanar deformation features as well as the composition of the meteorite itself. Enrichments of iron, nickel, cobalt, and chromium found in impact melt samples suggest that the meteorite waschondritic in nature.[4]
Once largely unknown to the outside world, the lake-filled crater had long been known to localInuit, who knew it as the "Crystal Eye of Nunavik" for its clear water. World War II pilots often used the almost perfectly circular landmark as a navigational aid.[5]
On June 20, 1943, aUnited States Army Air Force plane on a meteorological flight over the Ungava region of Quebec Province took a photograph that showed the wide crater rim rising up above the landscape. In 1948, theRoyal Canadian Air Force covered the same remote area as part of its program of photomapping Canada, though these photographs were not made publicly available until 1950. Ontario diamond prospector Frederick W. Chubb became interested by the strange terrain shown in the photographs and sought the opinion of geologist V. Ben Meen of theRoyal Ontario Museum. Chubb hoped that the crater was that of anextinct volcano, in which case the area might containdiamond deposits similar to those ofSouth Africa. However, Meen's knowledge of Canadian geology tentatively ruled out a volcanic origin. Meen subsequently made a brief trip by air to the crater with Chubb in 1950; it was on this trip that Meen proposed the name "Chubb Crater" for the circular feature and "Museum Lake" for the irregular body of water about 2 mi (3.2 km) north of the crater (now known as Laflamme Lake).
Following his return, Meen organized a proper expedition with the cooperation of theNational Geographic Society and theRoyal Ontario Museum. They travelled to the site in aPBY Catalinaflying boat in July 1951, landing on nearby Museum Lake.[6] Attempts to find fragments ofnickel-iron from the meteorite using mine detectors lent by theUS Army were unsuccessful due to the area's granite containing high levels ofmagnetite. Amagnetometer survey did find a magnetic anomaly under the crater's northern rim, however, indicating that a large mass of metal-bearing material was buried below the surface.[7] Meen led a second expedition to the crater in 1954. That same year its name was changed to "Cratère du Nouveau-Quebec" ("New Quebec Crater") at the request of theQuebec Geographic Board.
An expedition led by James Boulger in 1986 collected a small rock sample[8] from the area surrounding the New Quebec Crater.Petrographic analysis of this sample was conducted at theHarvard – Smithsonian Center for Astrophysics and reported to the 51stMeteoritical Society in 1988 byUrsula Marvin and David Kring.[9] Boulger returned to the area that summer, along with a research party led by M. A. Bouchard of theUniversity of Montreal. Three years later Canadian geologist Richard A. F. Grieve listed New Quebec among the 130 known terrestrial impact craters.[10] In 1992, Marvin and Kring documented the petrographic analysis of two impact melt samples collected within the crater rim.[11] They presented evidence ofshock metamorphism, which is consistent with similarimpact crater sites. In 1999, the name was again changed, to "Pingualuit". The crater and the surrounding area are now part of Canada'sPingualuit National Park, created on January 1, 2004.
Professor Reinhard Pienitz ofLaval University led a 2007 expedition to the crater. Sediment cores were extracted from the bottom of the lake, which were filled with fossilpollen,algae, and insect larvae. It was hoped that these finds would yield information about the climate dating back to the lastinterglacial period 120,000 years ago.[5] Preliminary results show that the upper 8.5 m (28 ft) sediment core contains records of two interglacial periods.[3]
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