The Pingualuit Crater (; from Inuit "pimple"), formerly called the "Chubb Crater" and later the "New Quebec Crater" (), is a relatively young impact crater located on the Ungava Peninsula in the administrative region of Nord-du-Québec, in Quebec, Canada. It is in diameter, and is estimated to be 1.4 ± 0.1 million years old (Pleistocene). The crater and the surrounding area are now part of Pingualuit National Park. The only species of fish in the crater lake is the Arctic char. Geography The crater is exposed to the surface, rising above the surrounding tundra, and is deep. The 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 the Great Lakes is 500 ppm). It is one of the most transparent lakes in the world, with a Secchi disk visible more than deep. The lake has no inlets or apparent outlets, so the water accumulates solely from rain and snow and is lost only through evaporation. Formation The crater was formed by a meteorite impact 1.4 Ma, as estimated by 40Ar/39Ar dating of impact melt rocks. An analysis of these rocks also revealed planar 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 was chondritic in nature. Discovery and scientific study Once largely unknown to the outside world, the lake-filled crater had long been known to local Inuit, 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. On June 20, 1943, a United 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, the Royal 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 the Royal Ontario Museum. Chubb hoped that the crater was that