Popigai crater
Encyclopedia
The Popigai crater in Siberia
, Russia is tied with Manicouagan Crater
as the fourth largest verified impact crater
on Earth. A large bolide impact created the 100 kilometres (62.1 mi) diameter crater 35.7 ± 0.2 (2σ) million years ago during the late Eocene
(Priabonian stage). The crater is 1½ hours (by helicopter) from the outpost of Khatanga
. It is designated by UNESCO
as a Geopark
, a site of special geological heritage.
For decades the Popigai crater has fascinated paleontologists and geologists, but the entire area was completely off limits because of the diamonds and the mines constructed by gulag
prisoners under Stalin
; however, a major investigatory expedition was undertaken in 1997 (IPEX 1997) which greatly advanced understanding of the enigmatic structure. The impactor in this event has been identified as either an 8 km (5 mi) diameter chondrite
asteroid
, or a 5 km (3.1 mi) diameter stony asteroid.
The shock pressures from the impact instantaneously transformed graphite
in the ground into diamond
s within a 13.6 km (8.5 mi) radius of the impact point. Diamonds are usually 0.5 to 2 mm (0.0196850393700787 to 0.078740157480315 in) in diameter; a few exceptional specimens are 10 mm (0.393700787401575 in) in size. The diamonds not only inherit the tabular shape of the original graphite grains but they additionally preserve the original crystal's delicate striations.
Popigai is the best example yet of the formation of a crater of this type. Three other craters are larger, but they are either buried (Chicxulub
), strongly deformed (Sudbury
), or deformed and severely eroded (Vredefort
).
There is a small possibility that Popigai impact crater formed simultaneous with the approximately 35 million year old Chesapeake Bay
and Toms Canyon
impact craters.
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...
, Russia is tied with Manicouagan Crater
Manicouagan crater
The Manicouagan Crater is one of the oldest known impact craters and is located primarily in Manicouagan Regional County Municipality in the Côte-Nord region of Québec, Canada, about north of the city of Baie-Comeau. Its northernmost part is located in Caniapiscau Regional County Municipality...
as the fourth largest verified impact crater
Impact crater
In the broadest sense, the term impact crater can be applied to any depression, natural or manmade, resulting from the high velocity impact of a projectile with a larger body...
on Earth. A large bolide impact created the 100 kilometres (62.1 mi) diameter crater 35.7 ± 0.2 (2σ) million years ago during the late Eocene
Eocene
The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...
(Priabonian stage). The crater is 1½ hours (by helicopter) from the outpost of Khatanga
Khatanga
Khatanga is a rural locality located on the Khatanga River, on the Taymyr Peninsula, in Krasnoyarsk Krai, Russia, south of the Arctic Ocean. It is one of the northernmost inhabited localities in Russia. Its elevation is 98 ft above sea level. Population: 3,450 . The name Khatanga means...
. It is designated by UNESCO
UNESCO
The United Nations Educational, Scientific and Cultural Organization is a specialized agency of the United Nations...
as a Geopark
Geopark
A Geopark is defined by the United Nations Educational, Scientific and Cultural Organization in its UNESCO Geoparks International Network of Geoparks programme as follows:...
, a site of special geological heritage.
For decades the Popigai crater has fascinated paleontologists and geologists, but the entire area was completely off limits because of the diamonds and the mines constructed by gulag
Gulag
The Gulag was the government agency that administered the main Soviet forced labor camp systems. While the camps housed a wide range of convicts, from petty criminals to political prisoners, large numbers were convicted by simplified procedures, such as NKVD troikas and other instruments of...
prisoners under Stalin
Joseph Stalin
Joseph Vissarionovich Stalin was the Premier of the Soviet Union from 6 May 1941 to 5 March 1953. He was among the Bolshevik revolutionaries who brought about the October Revolution and had held the position of first General Secretary of the Communist Party of the Soviet Union's Central Committee...
; however, a major investigatory expedition was undertaken in 1997 (IPEX 1997) which greatly advanced understanding of the enigmatic structure. The impactor in this event has been identified as either an 8 km (5 mi) diameter chondrite
Chondrite
Chondrites are stony meteorites that have not been modified due to melting or differentiation of the parent body. They formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids...
asteroid
Asteroid
Asteroids are a class of small Solar System bodies in orbit around the Sun. They have also been called planetoids, especially the larger ones...
, or a 5 km (3.1 mi) diameter stony asteroid.
The shock pressures from the impact instantaneously transformed graphite
Graphite
The mineral graphite is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Ancient Greek γράφω , "to draw/write", for its use in pencils, where it is commonly called lead . Unlike diamond , graphite is an electrical conductor, a semimetal...
in the ground into diamond
Diamond
In mineralogy, diamond is an allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions...
s within a 13.6 km (8.5 mi) radius of the impact point. Diamonds are usually 0.5 to 2 mm (0.0196850393700787 to 0.078740157480315 in) in diameter; a few exceptional specimens are 10 mm (0.393700787401575 in) in size. The diamonds not only inherit the tabular shape of the original graphite grains but they additionally preserve the original crystal's delicate striations.
Popigai is the best example yet of the formation of a crater of this type. Three other craters are larger, but they are either buried (Chicxulub
Chicxulub Crater
The Chicxulub crater is an ancient impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is located near the town of Chicxulub, after which the crater is named...
), strongly deformed (Sudbury
Sudbury Basin
The Sudbury Basin, also known as Sudbury Structure or the Sudbury Nickel Irruptive, is a major geologic structure in Ontario, Canada. It is the second-largest known impact crater or astrobleme on Earth, as well as one of the oldest....
), or deformed and severely eroded (Vredefort
Vredefort crater
Vredefort crater is the largest verified impact crater on Earth. It is located in the Free State Province of South Africa and named after the town of Vredefort, which is situated near its centre. The site is also known as the Vredefort dome or Vredefort impact structure...
).
There is a small possibility that Popigai impact crater formed simultaneous with the approximately 35 million year old Chesapeake Bay
Chesapeake Bay impact crater
The Chesapeake Bay impact crater was formed by a bolide that impacted the eastern shore of North America about 35 million years ago, in the late Eocene epoch. It is one of the best-preserved "wet-target" or marine impact craters, and the largest known impact crater in the U.S...
and Toms Canyon
Toms Canyon impact crater
The Toms Canyon impact crater is the site where one or more meteors struck the Atlantic continental shelf, about east of Atlantic City, New Jersey....
impact craters.