| Abstract: | An olivine nephelinite from the lower part of a thick alkalic ultrabasic and mafic sequence of volcanic rocks of the northeastern part of the Siberian flood basalt province (SFBP) yielded a 40ArX39Ar plateau age of 253.3 ?? 2.6 million years, distinctly older than the main tholeiitic pulse of the SFBP at 250.0 million years. Olivine phenocrysts of this rock showed 3He/4He ratios up to 12.7 times the atmospheric ratio; these values suggest a lower mantle plume origin. The neodymium and strontium isotopes, rare earth element concentration patterns, and cerium/lead ratios of the associated rocks were also consistent with their derivation from a near-cnondritic, primitive plume. Geochemical data from the 250-million-year-old volcanic rocks higher up in the sequence indicate interaction of this high-3He SFBP plume with a suboceanic-type upper mantle beneath Siberia. |
| Genre: | Article |
| ProdID: | 70019070 |
| Citation Author: | Basu, A. R.; Poreda, R. J.; Renne, P. R.; Teichmann, F.; Vasiliev, Y. R.; Sobolev, N. V.; Turrin, B. D. |
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| Citation End Page: | 825 |
| Citation Issue: | 5225 |
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| Citation Language: | English |
| Citation Larger Work Title: | Science |
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| Citation Number Of Pages: | 4 |
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| Citation Search Results Text: | High-3He plume origin and temporal-spatial evolution of the Siberian flood basalts; 1995; Article; Journal; Science; Basu, A. R.; Poreda, R. J.; Renne, P. R.; Teichmann, F.; Vasiliev, Y. R.; Sobolev, N. V.; Turrin, B. D. |
| Citation Start Page: | 822 |
| Citation Volume: | 269 |
| Citation Year: | 1995 |
| Type: | citation/reference |
| Text: | High-3He plume origin and temporal-spatial evolution of the Siberian flood basalts; 1995; Article; Journal; Science; Basu, A. R.; Poreda, R. J.; Renne, P. R.; Teichmann, F.; Vasiliev, Y. R.; Sobolev, N. V.; Turrin, B. D. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Sun, 1 Jan 1995 00:00 -0600 |
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