Fig. 7: Magma flux and radiogenic enrichment along the Ninety-East Ridge.

The Kerguelen plume was coupled to the SE Indian Ridge from >78 Ma to 43 Ma, producing the extensive volcanic products that comprise the Ninety-East Ridge. a Map of seafloor elevation from ETOPO1⁴¹ showing the position of the Kerguelen plume, the geometry of the SE Indian Ridge, and age progression of volcanic products which comprise the Ninety-East Ridge. Magma production calculated at multiple latitudinal cross-sections along the Ninety-East Ridge (see “Methods” section), overlain with isotope ratios of b ⁸⁷Sr/⁸⁶Sr, c ¹⁴³Nd/¹⁴⁴Nd, and d ²⁰⁷Pb/²⁰⁴Pb. Box plots are coloured by age, black lines indicate the median, blue triangles indicate the mean, and white circles indicate outliers. e Distance between the Kerguelen plume and SE Indian Ridge since 80 Ma, and rate of seafloor spreading between Australia, India, and Antarctica calculated from a plate reconstruction²⁶ using a fixed plume reference frame.