Siberian Flood Basalts
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چکیده
techniques and fractionation correcting to a 194Pt/ 95pt ratio of 0.9734 (38). 33. E. Anders and N. Grevesse, Geochim. Cosmochim. Acta 53, 197(1989). 34. M. P. Gorton, E. S. Schandl, A. J. Naldrett, Ocean Drilling Project Scientific Results, Leg 140, in press. 35. R. J. Walker et al., Geochim. Cosmochim. Acta 58, 4179 (1994); M. F. Horan, R. J. Walker, V. A. Fedorenko, G. K. Czamanske, ibid., in press. 36. J.-M. Luck and C. J. Allegre, Nature 302,130 (1983). 37. J. W. Morgan, G. A. Wandless, R. K. Petrie, A. J. Irving, Tectonophysics 75, 47 (1981). 38. P. De Bievre etal., J. Phys. Chem. Ref. Data 13, 809 (1984). 39. We thank R. Brett, B. Doe, S. Shirey, E. Widom, and two anonymous reviewers for reviewing preliminary versions of this manuscript. Supported by National Aeronautics and Space Administration grant NAGW 3625, NSF grant EAR 9117684, and the U.S. Geological Survey. We gratefully acknowledge this support.
منابع مشابه
Neodymium isotopes in flood basalts from the Siberian Platform and inferences about their mantle sources.
The initial isotopic compositions of Nd and Sr in basalts from the Central Siberian Plateau and other major continental flood basalts are reported. The continental flood basalts appear to be the product of partial melting of mantle sources that consist of relatively primitive undifferentiated material and are clearly distinct from midocean ridge basalts, which sample mantle reservoirs that have...
متن کاملRapid eruption of the siberian traps flood basalts at the permo-triassic boundary.
The Siberian Traps represent one of the most voluminous flood basalt provinces on Earth. Laser-heating (40)Ar/(39)Ar data indicate that the bulk of these basalts was erupted over an extremely short time interval (900,000 +/- 800,000 years) beginning at about 248 million years ago at mean eruption rates of greater than 1.3 cubic kilometers per year. Such rates are consistent with a mantle plume ...
متن کامل40Ar/39Ar dates from the West Siberian Basin: Siberian flood basalt province doubled.
Widespread basaltic volcanism occurred in the region of the West Siberian Basin in central Russia during Permo-Triassic times. New 40Ar/39Ar age determinations on plagioclase grains from deep boreholes in the basin reveal that the basalts were erupted 249.4 +/- 0.5 million years ago. This is synchronous with the bulk of the Siberian Traps, erupted further east on the Siberian Platform. The age ...
متن کاملUnderstanding cratonic flood basalts
The origin of continental flood basalts has been debated for decades. These eruptions often produce millions of cubic kilometers of basalt on timescales of only a million years. Although flood basalts are found in a variety of settings, no locale is more puzzling than cratonic areas such as southern Africa or the Siberian craton, where strong, thick lithosphere is breached by these large basalt...
متن کاملMass extinctions of life and catastrophic flood basalt volcanism.
E xtinctions have played an important role in the history of life by clearing out niches and fostering adaptive radiations. Major mass extinctions involving 70% to more than 90% of extant species occurred at least five times during the last 540 million years. The discovery by Alvarez et al. (1) that the end-Cretaceous (65 Mya) mass extinction coincided with evidence for the impact of an asteroi...
متن کاملGrowing magma chambers control the distribution of small-scale flood basalts
Small-scale continental flood basalts are a global phenomenon characterized by regular spatio-temporal distributions. However, no genetic mechanism has been proposed to explain the visible but overlooked distribution patterns of these continental basaltic volcanism. Here we present a case study from eastern China, combining major and trace element analyses with Ar-Ar and K-Ar dating to show tha...
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تاریخ انتشار 2009