Boreskov

PP‐3bioproductivity. Influence of volcanism of the Siberian trap province was very powerful. Allthe listed factors developed rather slowly and could not cause fast biotic catastrophe. Fossilsdistribution in sections of China has shown that extinction occurred during 3 Ma, howeverthe most intensive (in an interval less than 500 years) it was 251.4 Ma (Jin et al., 2000).The trigger of sharp changes on a background of gradually developing harmful ecologicalconditions were, possibly, impacts of large asteroids as it was on Cretaceous/Paleogeneboundary (Barash, 2008). Influence of impact events is proved only last years. Crater Bedout(diameter 180‐200 km) is found near Australia (Becker et al., 2006). Crater Araguainha (40km diameter) is found in Brazil (Lana, Marangoni, 2009). Crater Arganaty in Kazakhstan (315m diameter) is proved. Some probable impact structures demanding additional researchesare found. Possibly, the largest impact event in history of the Earth was impact event inAntarctica, on Wilkes Land (Von Frese et al. 2006). Geophysical methods reveal here a 500‐kilometer crater which is settling under the East‐Antarctic glacial sheet. Its probable age is250 Ma. Consequences of asteroid impacts are similar to consequences of volcanism. Theycaused global distribution of a dust, downturn of light exposure, change of temperature,acid rains, fires, etc.The analysis of the materials available leads to one of the most important inferencesthat all the terrestrial processes, the biospheric included, develop in close and continuousrelation with the extraterrestrial processes that occur beyond the solar system in the spaceto which our planet belongs (crossing by the Sun of spiral galactic sleeves, its fluctuationsperpendicularly to galactic plane or others).References[1]. Barash M. S. Evolution of the Mesozoic Oceanic Biota: Response to Abiotic Factors // Oceanology. 2008.Vol. 48. No. 4. P. 538–553.[2]. Becker L., Poreda R.J., Basu A.R. et al. Bedout: A Possible End‐Permian Impact Crater Offshore ofNorthwestern Australia // Science. 2004. V. 304. No. 5676. P. 1469‐1476.[3]. Catalogue of the Earth's Impact structures. Siberian Center for Global Catastrophes, Rus. Acad. of Sciences,Siberian division. Retrieved 2009‐08‐12. http://omzg.sscc.ru/impact/index1.html[4]. Isozaki Y. Integrated ''plume winter" scenario for the double‐phased extinction during the Paleozoic‐Mesozoic transition: The G‐LB and P‐TB events from a Panthalassan perspective // Jour. Asian Earth Sc.2009. V. 36. P. 459‐480.[5]. Jin Y.G., Wang Y., Wang W. et al. Pattern of Marine Mass Extinction near the Permian‐Triassic Boundary inSouth China // Science. 2000. V. 289. P. 432–436.[6]. Lana C., Marangoni Y. The Araguainha impact: a South American Permo–Triassic catastrophic event //Geology Today. 2009. V. 25. No. 1. P. 21‐28.[7]. Von Frese R.R, Potts L., Wells S. et al. "Permian‐Triassic mascon in Antarctica". Eos Trans. AGU, Jt. Assem.Suppl. 2006. V. 87 (36): Abstract T41A‐08.136