The Patomskiy crater or Patom crater (russian: Патомский кратер, ''Patomskiy Krater''), also known as , ''Konus Kolpakova'' "Kolpakov cone") is a peculiar

rock formation A rock formation is an isolated, scenic, or spectacular surface rock outcrop. Rock formations are usually the result of weathering and erosion sculpting the existing rock. The term ''rock formation'' can also refer to specific sediment ...

located in the

Bodaibo District Bodaybinsky District (russian: Бодайбинский райо́н) is an administrative district, one of the thirty-three in Irkutsk Oblast, Russia.Charter of Irkutsk Oblast Municipally, it is incorporated as Bodaybinsky Municipal District.Law ...

of the

Irkutsk Irkutsk ( ; rus, Иркутск, p=ɪrˈkutsk; Buryat language, Buryat and mn, Эрхүү, ''Erhüü'', ) is the largest city and administrative center of Irkutsk Oblast, Russia. With a population of 617,473 as of the 2010 Census, Irkutsk is ...

region of southeastern Siberia, from the district center

Bodaibo Bodaybo ( rus, Бодайбо, p=bədɐjˈbo) is a town and the administrative center of Bodaybinsky District in Irkutsk Oblast, Russia. It is located from Irkutsk, the administrative center of the oblast. Geography The town is located in the ...

. It is a large mound made of shattered

limestone block Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms when th ...

s on the slopes of the

Patom Highlands The Patom Highlands ( rus, Патомское нагорье) are a mountainous area in Eastern Siberia, Russia. Administratively most of the territory of the uplands is part of Irkutsk Oblast, with a smaller section in northern Transbaikal Krai.G ...

in an area of dense

taiga Taiga (; rus, тайга́, p=tɐjˈɡa; relates to Mongolic and Turkic languages), generally referred to in North America as a boreal forest or snow forest, is a biome characterized by coniferous forests consisting mostly of pines, spruce ...

. Its base diameter is about and its height about ; the cone's crown is ring-shaped, and in its center there is a smaller mound with a height of about . The volume of the crater is estimated as , with a weight of about one million tons. The Patomskiy crater was discovered in 1949 by Russian geologist Vadim Kolpakov. Its origins have been subject of intense scientific interest, with hypotheses including

meteorite A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or Natural satellite, moon. When the ...

volcanic A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates a ...

and gaseous origin, but to date no definite proof has been given. Through

dendrochronology Dendrochronology (or tree-ring dating) is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed. As well as dating them, this can give data for dendroclimatology, the study of climate and atmos ...

, the age of the crater is estimated to be 300 years old.

Theories of origin

Until recently, some scientists believed that the crater presents a large footprint of an ultra-dense meteorite, which had sunk underground upon impact. Another hypothesis was that it is a fragment of the Tunguska meteorite. Others believed that the crater is a result of a breakthrough of a deep pocket of natural gas. Several scientific expeditions have been sent to the crater but the nature of its origin remains a mystery. Astronomers and geophysicists from the

Irkutsk State Technical University National Research Irkutsk State Technical University (full name in Russian: ''Иркутский национальный исследовательский технический университет''), formerly Irkutsk State Technical Uni ...

, geochemists from the Institute of Geosphere Dynamics, RAS (Moscow), still believe that the crater may have a meteoric origin. A study conducted by V. S. Antipin and A. M. Fedorov showed, through morphological, structural and chemical data, that the crater is volcanic in origin. The presence of weathered breccias, the diameter/height ratio typical of volcanic cones, the absence of geochemical anomalies linked to cosmogenic origins, and its zoning of different ages, contradict clearly the meteorite hypotesis. The origin of the cone is therefore volcanic, caused by a rapid outbreak of deep fluids (CO2 and H2O) and gases (CO and H2).

Patom Crater Conference, 2010

In 2010,

Saint Petersburg Mining Institute Saint Petersburg Mining University (russian: Санкт-Петербургский горный университет), is Russia's oldest technical university, and one of the oldest technical colleges in Europe. It was founded on October 21, ...

held a scientific conference "Patom Crater 2010". Viktor Sergeyevich Antipin, head of a department at the St. Petersburg Institute of Geochemistry of the

Russian Academy of Sciences The Russian Academy of Sciences (RAS; russian: Росси́йская акаде́мия нау́к (РАН) ''Rossíyskaya akadémiya naúk'') consists of the national academy of Russia; a network of scientific research institutes from across t ...

(IG SB RAS), stated that "Since the 2006 expedition by the Institute of Geochemistry (IGC), RAS came to the conclusion that the Patomskiy crater probably originates from geological processes. An important fact is that no serious argument or evidence of a meteorite crater nature referred to by specialists had been given. There was not any new evidence to support the meteorite hypothesis." Antipin further noted that at the conference, for the first time, all the experts rejected the meteoric hypothesis. "Now it has only historical interest," he added. According to studies by Siberian scientists, the crater formed only 300 to 350 years ago. The zoning of the crater was caused by geological processes and intensive introduction of deep gas flows of matter, which led to the transformation of silicate rocks within the crater. "An important confirmation of these ideas were the result of geophysics from

Saint Petersburg Mining University Saint Petersburg Mining University (russian: Санкт-Петербургский горный университет), is Russia's oldest technical university, and one of the oldest technical colleges in Europe. It was founded on October 21, ...

and Yekaterinburg nstitute of Geophysics, UB RAS Performing gravimetric and geoelectrical investigations, they also came to the firm conviction that Patom crater has an origin of an endogenetic nature," said Antipin. According to geophysicists of St. Petersburg and Yekaterinburg, meteorite

impact crater An impact crater is a circular depression in the surface of a solid astronomical object formed by the hypervelocity impact of a smaller object. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters ...

s have a very different shape, and Patom crater is not one of them, he added.

References

External links

(in English)

*
englishrussia.com article 2013/05/27

(in Russian)