O¹⁸/O¹⁶ and C¹³/C¹² Ratios of Coexisting Minerals in the Oka and Magnet Cove Carbonatite Bodies
- Creators
- Conway, Clay M.
- Taylor, Hugh P., Jr.
Abstract
Oxygen isotope analyses were obtained for five magnetites (δ = +1.1 to +2.9), three biotites (+4.2 to +5.2), two melilites (+4.7 to +5.2), one apatite (+5.6), one niocalite (+4.2) and one pyrochlore (+1.2) from five samples of okaite and carbonatite in the Oka, Quebec, and Magnet Cove, Arkansas, complexes. Calcites from these and three other samples were analyzed for both O¹⁸/O¹⁶ and C¹³/C¹² (δO¹⁸ = +6.6 to +7.6, δC¹³ = -5.8 to -5.2). The order of increasing O¹⁸ concentration among minerals is consistent in all samples. Calculated whole-rock δO¹⁸ values (+4.7 to +5.9) are similar to those of mafic and ultramafic igneous rocks, and the δO¹⁸ and δC¹³ values of the calcites fall within the range previously suggested as being characteristic of primary igneous carbonatites. Crystallization temperatures, calculated from O¹⁸ fractionations for the pair calcite-magnetite, demonstrate that the okaites and carbonatites crystallized at about the same temperatures as, respectively, gabbros and "granitic" igneous rocks.
Additional Information
Appreciation is expressed to P. Yanagisawa for performing some of the fluorine extractions of oxygen, and to G. J. Wasserburg, M. Bass, A. R. Philpotts and A. E. Bence for supplying samples. Financial support for this research was provided by the National Science Foundation, grant no. GA 992.Additional details
- Alternative title
- O18/O16 and C13/C12 Ratios of Coexisting Minerals in the Oka and Magnet Cove Carbonatite Bodies
- Eprint ID
- 117681
- Resolver ID
- CaltechAUTHORS:20221101-222709625
- NSF
- GA 992
- Created
-
2022-11-04Created from EPrint's datestamp field
- Updated
-
2022-11-04Created from EPrint's last_modified field
- Other Numbering System Name
- Caltech Division of Geological Sciences
- Other Numbering System Identifier
- 1601