Dual Impact Craters

September 25, 2001


Provided by: Calvin Hamilton, NASA JSC, Earth Sciences
Summary authors & editors: Jim Foster

These side-by-side impact craters were formed simultaneously by two separate but related meteorite impacts. Such twin or dual impacts are rarely observed on Earth. This pair, known as the Clearwater Lakes Impact Craters, is believed to be about 300 million years old and is found in the crystalline bedrock of the Canadian shield in northwestern Quebec. The larger crater (left) has a diameter of approximately 20 miles and shows a prominent ring of islands having a diameter of about 6 miles. These islands (impact peaks) remained high and dry after the crater was flooded. However, the central peaks of the smaller Clearwater Lake (right) are now completely submerged.

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