CRYSTALLIZATION OF CHROMITE AND CHROMIUM SOLUBILITY IN BASALTIC MELTS
- DSpace Home
- →
- Геология России
- →
- ELibrary
- →
- View Item
JavaScript is disabled for your browser. Some features of this site may not work without it.
dc.contributor.author | Roeder P.L. | |
dc.contributor.author | Reynolds I. | |
dc.date.accessioned | 2020-11-06T05:22:07Z | |
dc.date.available | 2020-11-06T05:22:07Z | |
dc.date.issued | 1991 | |
dc.identifier | https://elibrary.ru/item.asp?id=10499963 | |
dc.identifier.citation | Journal of Petrology, 1991, , 5, 909 | |
dc.identifier.issn | 0022-3530 | |
dc.identifier.uri | https://repository.geologyscience.ru/handle/123456789/18486 | |
dc.description.abstract | The equilibrium between chromite and melt has been determined on four basalts at temperatures of 1200–1400°C over a range of oxygen fugacity (fo2) and pressures of 1 atm and 10 kb. The Cr content of chromite-saturated melts at 1300°C and 1 atm ranges from 0?05 wt.% Cr2O3 at a log fo2= ?3 to 1?4 wt.% at a log fo2=?12?8. The Cr2+/Cr3+ of melt increases with decreasing fo2 and is estimated by assuming a constant partitioning of Cr3+ between chromite and melt at constant temperature. The estimated values of Cr2+/Cr3+ in the melt are at fo2 values of 4–5 orders of magnitude lower than the equivalent Fe2+/Fe3+ values. The Cr/(Cr+Al) of chromite coexisting with melt at constant temperature changes little with variation of fo2 below log fo2=?6. Five experiments at 10 kb indicate that Cr2O3 dissolved in the melt is slightly higher and the Cr/(Cr + Al) of coexisting chromite is slightly lower than experiments at 1 atm pressure. Thus variation in total pressure cannot explain the large variations of Cr/(Cr + Al) that are common to mid-ocean ridge basalt (MORB) chromite. Experiments on a MORB at 1 atm at fo2 values close to fayalite-magnetite-quartz (FMQ) buffer showed that the Al2O3 content of melt is highly sensitive to the crystallization or melting of plagioclase, and consequently coexisting chromite shows a large change in Cr/(Cr + Al). It would appear, therefore, that mixing of a MORB magma containing plagioclase with a hotter MORB magma undersaturated in plagioclase may give rise to the large range of Cr/(Cr + Al) observed in some MORB chromite. | |
dc.title | CRYSTALLIZATION OF CHROMITE AND CHROMIUM SOLUBILITY IN BASALTIC MELTS | |
dc.type | Статья |
Files in this item
Files | Size | Format | View |
---|---|---|---|
There are no files associated with this item. |
This item appears in the following Collection(s)
-
ELibrary
Метаданные публикаций с сайта https://www.elibrary.ru