Lac Manicouagan, Quebec, Canada. I stitched together a series of false color images from the Sentinel-2 satellite in order to produce this image, captured on August 2019. Now considered an annular lake, Manicouagan’s formation began around 214 million years ago from a 5km wide meteor. Today, the lake exists because of a dam, which fills the inner 70km diameter ring from the impact. While difficult to visualize without topographic data, the outer crater ring spans nearly 100km, making it the 6th largest impact crater on Earth by size. Meanwhile, the plateau in the middle formed through post-impact uplift, by which the compressed crust returned to gravitational equilibrium (isostasy) over millennia.
For more information on terrestrial impact craters, check out The Astronaut’s Guide to Terrestrial Impact Craters (Richard A. F. Grieve, Lunar and Planetary Institute Technical Report, 1981-1998).
Sentinel-2 (ESA) image courtesy of the U.S. Geological Survey.