Ilumetsa crater | |
---|---|
Impact crater/structure | |
Confidence | Probable |
Diameter | 80 m (260 ft) |
Age | 7 ka |
Exposed | Yes |
Drilled | Yes |
Location | |
Coordinates | 57°57′36.17″N27°24′10.43″E / 57.9600472°N 27.4028972°E |
Country | Estonia |
Ilumetsa is a set of two probable meteorite craters [1] in Estonia. [ ambiguous ]
The Ilumetsa site is located in south eastern Estonia and it consists of two structures, located 725 m from each other. Their diameters are: 75–80 m and ~50 m. Their true depths are about 8 and 3.5 m, respectively. [2] Both structures are surrounded by a rim up to a few meters high: the rims are highest in their eastern parts with maximum rim heights of Ilumetsa Large 4.5 m and 1.5 m for Ilumetsa Small.
The Large Ilumetsa structure has been dated by radiocarbon dating the gyttja and peat from the very bottom of the crater shaped depression. [3] The lowermost organic beds were dated to 6030 +/-100 14C years (7170– 6660 cal. years BP). Recent radiocarbon dating charcoals buried within assumed proximal ejecta blankets of these crater-like features showed Ilumetsa Large and Ilumetsa Small formed simultaneously between 7170 and 7000 cal. years BP. [4]
No clear meteorite fragments or shock metamorphic effects were ever found around those structures. Because of that Ilumetsa is not a proven impact crater. However, indirect lines of evidence are enough to call it a "probable" impact site. It is: 1) presence of deformed sedimentary beds (including the rim consisting of sands mixed with numerous clayey till lenses;, [5] 2) only a small thickness of glacial sediments, [2] 3) simultaneous formation of both structures as showed by radiocarbon dating. [4]
Meteor Crater or Barringer Crater is an impact crater about 37 mi (60 km) east of Flagstaff and 18 mi (29 km) west of Winslow in the desert of northern Arizona, United States. The site had several earlier names, and fragments of the meteorite are officially called the Canyon Diablo Meteorite, after the adjacent Canyon Diablo.
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.
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).
The Araguainha crater or Araguainha dome is an impact crater on the border of Mato Grosso and Goiás states, Brazil, between the villages of Araguainha and Ponte Branca. With a diameter of 40 kilometres (25 mi), it is the largest known impact crater in South America.
Kaali is a group of nine meteorite craters in the village of Kaali on the Estonian island of Saaremaa. Most recent estimates put its formation shortly after 1530–1450 BC. It was created by an impact event and is one of the few impact events that has occurred in a populated area.
Lappajärvi is a lake in Finland, in the municipalities of Lappajärvi, Alajärvi and Vimpeli. It is formed in a 23 km (14 mi) wide, partly eroded meteorite impact crater. The lake is part of Ähtävänjoki basin together with Lake Evijärvi that is located downstream (north) of it.
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).
Roter Kamm is a meteorite crater, located in the Sperrgebiet, within the Namibian section of the Namib Desert, approximately 80 kilometres (50 mi) north of Oranjemund and 12 kilometres (7.5 mi) southwest of Aurus Mountain in the ǁKaras Region. The crater is 2.5 kilometres (1.6 mi) in diameter and is 130 metres (430 ft) deep. The age is estimated at 4.81 ± 0.5 Ma, placing it in the Pliocene. The crater is exposed at the surface, but its original floor is covered by sand deposits at least 100 metres (330 ft) thick.
Tswaing is an impact crater enclosed by a 1,946 ha nature reserve, situated in northern Gauteng province, South Africa. The crater and reserve are situated on a base of ancient granite of the Bushveld Igneous Complex, some 40 km to the north-northwest of Pretoria. This astrobleme is 1.13 km in diameter and 100 m deep and its age is estimated to be 220,000 ± 52,000 years (Pleistocene). The impactor is believed to have been a chondrite or stony meteorite some 30 to 50 m in diameter that was vaporised during the impact event. Morokweng impact structure, another South African crater of chondrite origin, lies north-west of Vryburg. Since 1996 it falls under the auspices of Ditsong Museums of South Africa.
The Vredefort impact structure is the largest verified impact structure on Earth. The crater, which has since been eroded away, has been estimated at 170–300 kilometres (110–190 mi) across when it was formed. The remaining structure, comprising the deformed underlying bedrock, is located in present-day Free State province of South Africa. It is named after the town of Vredefort, which is near its centre. The structure's central uplift is known as the Vredefort Dome. The impact structure was formed during the Paleoproterozoic Era, 2.023 billion years ago. It is the second-oldest known impact structure on Earth, after Yarrabubba.
Lake Bosumtwi is the only natural lake in Ghana. It is situated within an ancient impact crater that is about 10.5 kilometres (6.5 mi) in diameter. It is about 30 km (19 mi) south-east of Kumasi, the capital of Ashanti, and is a popular recreational area. There are about 30 villages near the crater lake of Lake Bosumtwi, with a combined population of about 70,000. The most popular amongst the villages where tourists usually settle is Abono.
The rim or edge of an impact crater is the part that extends above the height of the local surface, usually in a circular or elliptical pattern. In a more specific sense, the rim may refer to the circular or elliptical edge that represents the uppermost tip of this raised portion. If there is no raised portion, the rim simply refers to the inside edge of the curve where the flat surface meets the curve of the crater bottom.
The Corossol structure, which is also known as the Corossol crater, is a circular, 4.3-by-3.9-kilometre in diameter, underwater bedrock feature that is exposed on the gulf floor of the northwestern Gulf of Saint Lawrence 20-kilometre (12 mi) offshore of the city of Sept-Îles, Quebec, in eastern Canada. It is hypothesized to be a possible pre-Pleistocene, extraterrestrial impact structure. It lies underwater at a depth of 40–208-metre (131–682 ft). This underwater feature was found during the study of high-resolution bathymetric and sub-bottom profiler data collected south of the city of Sept-Iles in the northwestern Gulf of Saint Lawrence.
As of June 2018, 12 confirmed impact structures have been found in Finland. They are listed below, sorted by original diameter.
Monturaqui is an impact crater in Chile. It lies south of the Salar de Atacama and was formed 663,000 ± 90,000 years ago by the impact of an IAB meteorite. It is 350 m × 370 m wide and 34 m (112 ft) deep and contains a salt pan. Only a few remnants of the meteorite that formed the crater have been collected, with most of the rocks being of local origin. The crater was discovered in 1962 and identified as an impact crater in 1966.
Yilan crater is an impact crater in China, situated to the northwest of the town of Yilan in Heilongjiang province. Its southern rim has eroded, but its northern rim is visible on the surface as a crescent-shaped ridge. It has a diameter of 1.85 km (1.15 mi) at its maximum extent, with the rim rising 150 m (490 ft) above the crater's basin. Radiocarbon dating shows its age to be only 46,100 to 52,500 years.
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