Osmium and neodymium isotopic constraints on the temporal and spatial evolution of Siberian flood basalt sources
Geochimica et Cosmochimica Acta
By: M.F. Horan, R.J. Walker, V.A. Fedorenko, and G.K. Czamanske
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Abstract
Picrites from the Gudchikhinsky suite, the oldest rocks examined, have ??Os of +5.3 to +6.1 and ??Nd of +3.7 to +4.0. The osmium and neodymium isotopic compositions of these rocks are similar to some modern ocean-island basalts (OIB), consistent with their derivation from an mantle plume. Picrites from the stratigraphically higher Tuklonsky suite have similar ??Os of +3.4 to +6.5, but ??Nd of -0.9 to -2.6. The similar ??Os, but lower ??Nd , suggest that some magmas from the same OIB-type, mantle source were contaminated by lithospheric components. A differentiated ankaramite flow, associated with the top of the stratigraphically higher Morongovsky suite, has ??Os of +9.8 to +10.2 and ??Nd of +1.3 to +1.4. The higher ??Os may indicate that the plume source was heterogeneous with respect to osmium isotopic composition, consistent with osmium isotopic measurements in rocks from other plume sources. Mg-rich, alkaline rocks (meymechites) from the Guli area that erupted much nearer the end of the flood-basalt event have ??Os of -1.2 to -2.6 and ??Nd of +3.7 to +4.9. These rocks were probably produced by low degrees of partial melting of mantle after the main stages of flood-basalt production. -from Authors
Suggested Citation
Horan, M., Walker, R., Fedorenko, V., and Czamanske, G., 1995, Osmium and neodymium isotopic constraints on the temporal and spatial evolution of Siberian flood basalt sources: Geochimica et Cosmochimica Acta, v. 59, no. 24, p. 5159-5168, https://doi.org/10.1016/0016-7037(96)89674-8.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Osmium and neodymium isotopic constraints on the temporal and spatial evolution of Siberian flood basalt sources |
| Series title | Geochimica et Cosmochimica Acta |
| DOI | 10.1016/0016-7037(96)89674-8 |
| Volume | 59 |
| Issue | 24 |
| Year Published | 1995 |
| Language | English |
| Larger Work Type | Article |
| Larger Work Subtype | Journal Article |
| Larger Work Title | Geochimica et Cosmochimica Acta |
| First page | 5159 |
| Last page | 5168 |