An impact crater is a depression in the surface of a solid astronomical body formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Impact craters are typically circular, though they can be elliptical in shape or even irregular due to events such as landslides. Impact craters range in size from microscopic craters seen on lunar rocks returned by the Apollo Program to simple bowl-shaped depressions and vast, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth.
An impact event is a collision between astronomical objects causing measurable effects. Impact events have been found to regularly occur in planetary systems, though the most frequent involve asteroids, comets or meteoroids and have minimal effect. When large objects impact terrestrial planets such as the Earth, there can be significant physical and biospheric consequences, as the impacting body is usually traveling at several kilometres a second, though atmospheres mitigate many surface impacts through atmospheric entry. Impact craters and structures are dominant landforms on many of the Solar System's solid objects and present the strongest empirical evidence for their frequency and scale.
The Río Cuarto craters are a purported group of impact craters located in Córdoba Province, Argentina. Research published in 2002 indicates that they are more likely a result of aeolian processes.
Manicouagan Reservoir is an annular lake in central Quebec, Canada, covering an area of 1,942 km2 (750 sq mi). The lake island in its centre is known as René-Levasseur Island, and its highest point is Mount Babel. The structure was created 214 (±1) million years ago, in the Late Triassic, by the impact of a meteorite 5 km (3 mi) in diameter. The lake and island are clearly seen from space and are sometimes called the "eye of Quebec". The lake has a volume of 137.9 km3 (33.1 cu mi).
Iso-Naakkima is a lake in Southern Savonia, Finland, about 10 km south of the town of Pieksämäki. It is notable for having an eroded impact crater under the northwestern part of the lake. It is one of the oldest known, about 1200 million years old. Of the known craters older than a billion years old, it is also one of the smallest being only 3 km in diameter.
Karakul or Qarokul is an endorheic lake, 25 km (16 mi) in diameter, located within a 52 km (32 mi) impact crater. It is located in the Tajik National Park in the Pamir Mountains in Tajikistan.
Maple Creek is a subterranean meteorite crater in Saskatchewan, Canada. It is 6 km (3.7 mi) in diameter and the age is estimated to be less than 75 million years. The crater is buried beneath younger sediment and cannot be seen at the surface.
Marquez crater is a meteorite crater located in Leon County, Texas near the small town of Marquez about 177 km (110 mi) northeast of Austin, Texas, United States.
Mistastin crater is a meteorite crater in Labrador, Canada which contains the roughly circular Mistastin Lake. The lake is approximately 16 km (9.9 mi) in diameter, while the estimated diameter of the original crater is 28 km (17 mi). The age of the crater is calculated to be 36.6 ± 2 million years (Eocene).
Obolon' crater is a 20 km (12 mi) diameter buried meteorite impact crater situated about 200 km (120 mi) southeast of Kyiv in Ukraine . The site has been drilled, which revealed the presence of shocked minerals and impact melt rock; the high chlorine content of the latter suggesting that the area was covered by shallow sea at the time of impact. One estimate puts the age at 169 ± 7 million years.
The Popigai impact structure is the eroded remnant of an impact crater in northern Siberia, Russia. It is tied with the Manicouagan structure as the fourth largest verified impact structure on Earth. A large bolide impact created the 100-kilometre (62 mi) diameter crater approximately 35 million years ago during the late Eocene epoch. It might be linked to the Eocene–Oligocene extinction event.
Puchezh-Katunki is a meteor crater located in the Nizhny Novgorod Oblast of the Volga Federal District, Russia. It is 80 km (50 mi) in diameter. Argon–argon dating has constrained the age of formation to be 195.9 ± 1.0 million years old, placing it within the Sinemurian stage of the Early Jurassic. The crater is not exposed to the surface, but appears as variation in the vegetation. The Earth Impact Database lists a rim-to-rim diameter of 40 kilometres (25 mi).
The Rock Elm Disturbance is an impact crater in Pierce County, Wisconsin, United States, roughly 40 kilometres (25 mi) southwest of Menomonie. The disturbance is named for Rock Elm, Wisconsin, a nearby town.
Sierra Madera crater is a meteorite crater (astrobleme) in southwestern Pecos County, Texas, United States. The central peak of the rebound structure of the impact crater rises 793 ft (242 m) above the surrounding land. The peak is visible from U.S. Highway 385 between Fort Stockton, Texas and Marathon, Texas. The Sierra Madera crater is located on private property on the La Escalera Ranch.
Woodleigh is a large meteorite impact structure (astrobleme) in Western Australia, centred on Woodleigh Station east of Shark Bay, Gascoyne region. A team of four scientists at the Geological Survey of Western Australia and the Australian National University, led by Arthur J. Mory, announced the discovery in the 15 April 2000 issue of Earth and Planetary Science Letters.
The Tunnunik impact structure, formerly known as the Prince Albert Impact Crater, is a recently confirmed meteorite impact structure. It is located on Prince Albert Peninsula in the northwestern part of Victoria Island[A] in Canada's Northwest Territories.
