| 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[8], and Dy/Yb ratios increase, while Na[8] remains unchanged and Fe[8] 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... |
