An impact in the Pleistocene
Approximately 1.4 million years ago, a chondrite meteorite struck the Earth's crust, creating the Pingualuit Crater. The impact released energy estimated to be 8,500 times more powerful than the atomic bomb at Hiroshima. The resulting structure is an almost perfectly circular simple crater with a diameter of 3.44 kilometers. Its raised rim rises 160 meters above the surrounding tundra, and the crater itself is 400 meters deep.
Over millennia, the crater filled with rain and snowmelt, forming Pingualuk Lake. The lake has no inlets or outlets, creating a closed system where water is lost only to evaporation. This isolation is the reason for its exceptional purity. The water has a salinity level of less than 3 parts per million, dramatically lower than the 500 ppm found in the Great Lakes. This purity results in extreme clarity, with a Secchi disk—a tool for measuring water transparency—visible to depths of more than 35 meters. The lake itself is 267 meters deep, making it one of the deepest in North America.
A climate change time machine
The crater's geology and the lake's isolated nature make it an invaluable site for scientific research. Because the deep lake and its protective rim shielded the bottom sediments from glacial scouring during past ice ages, these layers remain remarkably undisturbed. This provides a continuous and well-preserved natural archive of environmental history.
In 2007, a scientific expedition led by Professor Reinhard Pienitz of Laval University drilled into the lakebed to extract sediment cores. A nine-meter core was retrieved, containing fossilized pollen, algae, and insect larvae. Analysis of these samples shows climate conditions dating back at least 120,000 years, covering two previous interglacial periods. These preserved sediments allow scientists to reconstruct past climate patterns with a level of detail unavailable in most other North American lakes.
The only fish species in the lake is the Arctic char. Scientists believe these fish have been living in isolation for thousands of years, showing genetic evolution and adaptation in freshwater ecosystems.