| Autor: |
Michael Bau, Peter Dulski, Nicolas J. Beukes, Axel Höhndorf |
| Přispěvatelé: |
4.3 Organic Geochemistry, 4.0 Chemistry and Material Cycles, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum |
| Rok vydání: |
1997 |
| Předmět: |
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| Zdroj: |
Journal of Geology |
| Popis: |
Neodymium isotopic data are reported for pure chemical sediments from the Siderian Kuruman and Penge Iron-Formations (IFs) in the Transvaal Supergroup, South Africa. From a large sample set for which petrographical and chemical data was available, we selected samples which best represent the pure chemical sediment and still carry the primary rare-earth element (REE) distribution for isotope analyses. Both the Kuruman IF ( + 1.9 and +1.1) and the Penge IF (+ 0.2 and -0.2) show $$\epsilon_{Nd} (2.5 Ga)$$ values more radiogenic than published values for epiclastic sediments from the slightly older Black Reef Formation (-5.1 to -3.2). This suggests that REE and iron in the Transvaal IFs were predominantly, though not exclusively, derived from hydrothermal alteration of oceanic crust. The $$\epsilon_{Nd} (2.5 Ga)$$ value of the Kuruman IF is similar to that proposed for the Hamersley IF in western Australia, suggesting that $$\epsilon_{Nd}(t) values of + 1 \pm 1$$ were typical of IF-depositing open ocean water... |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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