Isotopic fractionation of oxygen and carbon in decomposed lower-mantle inclusions in diamond
| Autor: | Felix V. Kaminsky, Richard Wirth, Ian D. Hutcheon, J. E. P. Matzel, Ben Jacobsen |
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| Rok vydání: | 2016 |
| Předmět: |
Calcite
010504 meteorology & atmospheric sciences δ13C δ18O Geochemistry Mineralogy Diamond Fractionation engineering.material 010502 geochemistry & geophysics 01 natural sciences Wollastonite Mantle (geology) chemistry.chemical_compound Geophysics chemistry Geochemistry and Petrology engineering Monticellite Geology 0105 earth and related environmental sciences |
| Zdroj: | Mineralogy and Petrology |
| Popis: | Two carbonatitic mineral assemblages, calcite + wollastonite and calcite + monticellite, which are encapsulated in two diamond grains from the Rio Soriso basin in the Juina area, Mato Grosso State, Brazil, were studied utilizing the NanoSIMS technique. The assemblages were formed as the result of the decomposition of the lower-mantle assemblage calcite + CaSi-perovskite + volatile during the course of the diamond ascent under pressure conditions from 15 to less than 0.8 GPa. The oxygen and carbon isotopic compositions of the studied minerals are inhomogeneous. They fractionated during the process of the decomposition of primary minerals to very varying values: δ18O from −3.3 to +15.4 ‰ SMOW and δ13C from −2.8 to +9.3 ‰ VPDB. These values significantly extend the mantle values for these elements in both isotopically-light and isotopically-heavy areas. |
| Databáze: | OpenAIRE |
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