Clearwater Lakes

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Clearwater Lakes as seen from space shuttle (North lies roughly to the bottom left)

The Clearwater Lakes (officially known by their French name, Lac à l'Eau Claire [1]) are a pair of circular lakes on the Canadian Shield in Quebec, Canada, near Hudson Bay.

The lakes fill depressions that are interpreted as paired impact craters (astroblemes).^[1] The eastern and western craters are 26 km and 36 km in diameter, respectively. Each crater has same age, 290 ± 20 million years (Permian), and it is believed that they formed simultaneously. The impactors may have been gravitationally bound as a binary asteroid. This suggestion was first made by Thomas William Hamilton in a letter to Sky & Telescope magazine in support the then-controversial theory that asteroids may possess moons.^{[citation needed]}

The lakes are actually a single body of water with a sprinkling of islands forming a "dotted line" between the eastern and western parts. The name is due to the clear water it holds. There are actually 25 lakes of that name in the province (26 if you count the "Petit lac à l'Eau Claire" —the "Small Clearwater Lake"). These are the largest and northernmost.

[edit] References

^ Robertson, P.B. & Grieve, R.A.F. 1975 Impact structures in Canada: Their recognition and characteristics. Journal of the Royal Astronomical Society of Canada, v. 69, pp. 1-21.