Heterogeneity in southern Central Indian Ridge MORB: Implications for ridge–hot spot interaction
Article first published online: 19 MAR 2005
Copyright 2005 by the American Geophysical Union.
Geochemistry, Geophysics, Geosystems
Volume 6, Issue 3, March 2005
How to Cite
2005), Heterogeneity in southern Central Indian Ridge MORB: Implications for ridge–hot spot interaction, Geochem. Geophys. Geosyst., 6, Q03E20, doi:10.1029/2004GC000798., , , and (
- Issue published online: 19 MAR 2005
- Article first published online: 19 MAR 2005
- Manuscript Accepted: 9 FEB 2005
- Manuscript Revised: 12 JAN 2005
- Manuscript Received: 8 JUL 2004
- Central Indian Ridge;
- hot spot–ridge interaction;
- MORB geochemistry
 Between the Rodrigues Triple Junction and the Marie Celeste fracture zone, basalts from the Central Indian Ridge (CIR) exhibit an enrichment in incompatible elements that increases in intensity northward. In addition, H2O/TiO2, Al, and Dy/Yb ratios increase, while Na remains unchanged and Fe decreases. Evolution of the enriched magma appears to be affected by elevated water contents, which lower the mantle solidus, thereby increasing the initial depth of melting, as well as delaying plagioclase crystallization. However, the enrichment affecting the northern samples is not a just function of hydrous mantle melting and crystallization. Instead of trending toward a small melt fraction from the mantle, as predicted by hydrous melting models, the CIR samples lie on a mixing line between N-MORB and a source component that closely resembles present-day Réunion hot spot lavas. Thus it appears that while hydrous melting and crystallization affect the CIR, the enriched and wet mantle originates from the Réunion hot spot, where it migrates eastward toward the CIR, against the direction of motion of the lithosphere.