Editing Siberia (section)

===Geology===
The West Siberian Plain, consisting mostly of [[Cenozoic]] alluvial deposits, is somewhat flat. In the mid-Pleistocene, many deposits on this plain resulted from [[Proglacial lake|ice dam]]s which produced a large [[glacial lake]]. This mid- to late-[[Pleistocene]] lake blocked the northward flow of the [[Ob (river)|Ob]] and [[Yenisey]] rivers, resulting in a redirection southwest into the [[Caspian Sea|Caspian]] and [[Aral Sea|Aral]] seas via the [[Turgai Valley]].<ref>[http://www.esd.ornl.gov/projects/qen/lake.html Lioubimtseva E.U., Gorshkov S.P. & Adams J.M.; ''A Giant Siberian Lake During the Last Glacial: Evidence and Implications''; Oak Ridge National laboratory] {{webarchive|url= https://web.archive.org/web/20061213101647/http://www.esd.ornl.gov/projects/qen/lake.html |date= 13 December 2006 }}</ref> The area is very swampy, and soils are mostly peaty [[histosol]]s and, in the treeless northern part, [[histels]]. In the south of the plain, where [[permafrost]] is largely absent, rich grasslands that are an extension of the [[Kazakh Steppe]] formed the original vegetation, most of which is no longer visible.{{why?|date= April 2015}}
[[File:2006-07 altaj belucha.jpg|thumb|[[Belukha Mountain]]]]
[[File:Yakutia - DSC 6164.jpg|thumb|[[Verkhoyansk Range]]]]
The Central Siberian Plateau is an ancient [[craton]] (sometimes named ''Angaraland'') that formed an independent [[continent]] before the [[Permian]] (see the [[Siberia (continent)|Siberian continent]]). It is exceptionally rich in minerals, containing large deposits of [[gold]], [[diamond]]s, and ores of [[manganese]], [[lead]], [[zinc]], [[nickel]], [[cobalt]], and [[molybdenum]]. Much of the area includes the [[Siberian Traps]]—a [[large igneous province]]. A massive eruptive period approximately coincided with the [[Permian–Triassic extinction event]]. The volcanic event is one of the largest known [[volcanic eruptions]] in [[History of the Earth|Earth's history]]. Only the extreme northwest was [[glaciated]] during the [[Quaternary]], but almost all is under exceptionally deep permafrost, and the only [[tree]] that can thrive, despite the warm summers, is the deciduous [[Siberian Larch]] (''Larix sibirica'') with its very shallow roots. Outside the extreme northwest, the [[taiga]] is dominant, covering a significant fraction of the entirety of Siberia.<ref>C. Michael Hogan. 2011. [http://www.eoearth.org/article/Taiga?topic=58071 ''Taiga''. eds. M.McGinley & C.Cleveland. Encyclopedia of Earth. National Council for Science and the Environment. Washington DC]</ref> Soils here are mainly [[Gelisol|turbels]], giving way to [[spodosols]] where the active layer becomes thicker and the ice-content lower.

The ''Lena-Tunguska petroleum province'' includes the Central Siberian platform (some authors refer to it as the "Eastern Siberian platform"), bounded on the northeast and east by the [[Late Carboniferous]] through [[Jurassic]] Verkhoyansk [[foldbelt]], on the northwest by the [[Paleozoic]] Taymr foldbelt, and on the southeast, south and southwest by the Middle [[Silurian]] to [[Middle Devonian]] Baykalian foldbelt.<ref name=Meyerhof>Meyerhof, A. A., 1980, "Geology and Petroleum Fields in Proterozoic and Lower Cambrian Strata, Lena-Tunguska Petroleum Province, Eastern Siberia, USSR", in ''Giant Oil and Gas Fields of the Decade: 1968–1978'', AAPG Memoir 30, Halbouty, M. T., editor, Tulsa: American Association of Petroleum Geologists, {{ISBN|0891813063}}</ref>{{rp|228}} A regional geologic reconnaissance study begun in 1932 and followed by surface and subsurface mapping revealed the Markova-Angara Arch ([[anticline]]). This led to the discovery of the Markovo Oil Field in 1962 with the Markovo—1 well, which produced from the [[Early Cambrian]] Osa Horizon [[Shoal|bar]]-[[sandstone]] at a depth of {{convert|2156|m|ft}}.<ref name=Meyerhof/>{{rp|243}} The ''Sredne-Botuobin Gas Field'' was discovered in 1970, producing from the Osa and the [[Proterozoic]] Parfenovo Horizon.<ref name=Meyerhof/>{{rp|244}} The Yaraktin Oil Field was discovered in 1971, producing from the [[Vendian]] Yaraktin Horizon at depths of up to {{convert|1750|m|ft}}, which lies below [[Permian]] to [[Lower Jurassic]] [[Flood basalt|basalt traps]].<ref name=Meyerhof/>{{rp|244}}