Evidence for compositionally distinct upper mantle plumelets since the early history of the Tristan-Gough hotspot

• Published in: Nature communications Vol. 14; no. 1; p. 3908
• Main Authors: Homrighausen, Stephan, Hoernle, Kaj, Hauff, Folkmar, Hoyer, Patrick A, Haase, Karsten M, Geissler, Wolfram H, Geldmacher, Jörg
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 03.07.2023; Nature Publishing Group UK; Nature Portfolio
• Subjects: Cretaceous; Earth mantle; Geochemistry; Hot spots (geology); Lava; Lithosphere; Mathematical models; Numerical models; Plates (tectonics); Plumes; Seamounts; Upper mantle; Zonation
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-39585-0

Recent studies indicate that mantle plumes, which transfer material and heat from the earth's interior to its surface, represent multifaceted upwellings. The Tristan-Gough hotspot track (South Atlantic), which formed above a mantle plume, documents spatial geochemical zonation in two distinct sub-tracks since ~70 Ma. The origin and the sudden appearance of two distinct geochemical flavors is enigmatic, but could provide insights into the structural evolution of mantle plumes. Sr-Nd-Pb-Hf isotope data from the Late Cretaceous Rio Grande Rise and adjacent Jean Charcot Seamount Chain (South American Plate), which represent the counterpart of the older Tristan-Gough volcanic track (African Plate), extends the bilateral-zonation to ~100 Ma. Our results support recent numerical models, demonstrating that mantle plumes can split into distinct upper mantle conduits, and provide evidence that these plumelets formed at the plume head-to-plume tail transition. We attribute the plume zonation to sampling the geochemically-graded margin of the African Large Low-Shear-Velocity Province.