Cometary impacts into ocean: Thermodynamical equilibrium calculations of high-temperature O2 generation on the early Earth
| Autor: | Katja I. Panov, Pavle I. Premović |
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| Jazyk: | angličtina |
| Rok vydání: | 2002 |
| Předmět: | |
| Zdroj: | Journal of the Serbian Chemical Society, Vol 67, Iss 5, Pp 353-365 (2002) |
| ISSN: | 1820-7421 0352-5139 |
| Popis: | The early Earth's atmosphere apparently differed from the present atmosphere mainly in its lack of free O 2 , and this absence is believed to have been indispensable for the origin ofearly anaerobic life forms. One ofthe central problems in Earth science is to explain the apparent transition from the primitive atmosphere (free of O 2 ) to the present atmosphere which contains 21 % of the gas. Theoretical models suggest that the initial form of O 2 in the Earth's atmosphere may have been H 2 O, which was converted into atmospheric O 2 mainly through photosynthesis. We have investigated an alternative (abiotic) method for the conversion of H 2 O to O 2 : a high-temperature shock generated during a cometary impact into an ocean (or on land). The calculations presented here show that I % ofthe present level of O 2 could have resulted from an icy 1.3×10 1 6 kg comet entering the early (pre-oxygenic) Earth with a velocity of between about 11 and 30 km s - 1 . |
| Databáze: | OpenAIRE |
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