Siberian Traps
The Siberian Traps (Russian: Сибирские траппы Sibirskie trappi) form a large region of volcanic rock, known as a large igneous province, in the Russian region of Siberia. The massive eruptive event which formed the traps, one of the largest known volcanic events of the last 500 million years of Earth's geological history, continued for a million years and spanned the Permian–Triassic boundary, about 251 to 250 million years ago.
The term "traps" is derived from the Swedish word for stairs (trappa, or sometimes trapp), referring to the step-like hills forming the landscape of the region, which is typical of flood basalts.
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[edit] Geographical extent
Vast volumes of basaltic lava paved over a large expanse of primeval Siberia in a flood basalt event. Today the area covered is about 2 million km² – roughly equal to western Europe in land area – and estimates of the original coverage are as high as 7 million km². The original volume of lava is estimated to range from 1 to 4 million km³.
The area covered lies between 50° and 75° north latitude and 60° to 120° east longitude.
[edit] Origin
The source of the Siberian Traps basalt has variously been attributed to a mantle plume which impacted the base of the earth's crust and erupted through the Siberian Craton, or to processes related to plate tectonics.[1] This controversial scientific debate is ongoing.[2]
[edit] Impact on prehistoric life
This massive eruptive event spanned the Permian-Triassic boundary, about 250 million years ago, and is cited as a possible cause of the Permian-Triassic extinction event.[3] This extinction event, also called the Great Dying, affected all life on Earth, and is estimated to have killed 90% of species living at the time.[4] Life on land took 30 million years to recover from the environmental disruptions which may have been caused by the eruption of the Siberian Traps.[5]
[edit] Siberian Traps and nickel
The Siberian Traps are considered to have erupted via numerous vents over a period of roughly a million years or more, probably east and south of Norilsk in Siberia. Individual eruptions of basalt lavas could have exceeded 2,000 km3. The giant Norilsk-Talnakh nickel–copper–palladium deposit formed within the magma conduits in the main part of the Siberian Traps. The presence of extensive tuff and pyroclastic deposits suggests that a number of large explosive eruptions occurred during or before the eruptions of basaltic lavas. The presence of silicic volcanic rocks such as rhyolite is also indicative of explosive eruptions.
[edit] See also
[edit] Notes
- ^ Foulger, G.R. (2010). Plates vs. Plumes: A Geological Controversy. Wiley-Blackwell. ISBN 978-1-4051-6148-0. http://www.wiley.com/WileyCDA/WileyTitle/productCd-1405161485.html.
- ^ Czamanske, Gerald K.; Fedorenko, Valeri A. The Demise of the Siberian Plume, January 2004.
- ^ "Could Siberian volcanism have caused the Earth's largest extinction event?", Eurekalert!, 9 January 2012. Retrieved on 12 January 2012.
- ^ Benton M J (2005). When Life Nearly Died: The Greatest Mass Extinction of All Time. Thames & Hudson. ISBN 978-0500285732.
- ^ Sahney, S. and Benton, M.J. (2008). "Recovery from the most profound mass extinction of all time" (PDF). Proceedings of the Royal Society: Biological 275 (1636): 759–65. doi:10.1098/rspb.2007.1370. PMC 2596898. PMID 18198148. http://journals.royalsociety.org/content/qq5un1810k7605h5/fulltext.pdf.
[edit] External links
- The Siberian Traps
- The Siberian Traps, by Richard Cowen
- The Siberian Traps Large Igneous Province
- Toxic Gases Caused World's Worst Extinction
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