Homrighausen S, Hoernle K, Zhou H, Geldmacher J, Wartho JA, Hauff F, Werner R, Jung S, Morgan JP. Paired EMI-HIMU hotspots in the South Atlantic-Starting plume heads trigger compositionally distinct secondary plumes?
Sci Adv 2020;
6:eaba0282. [PMID:
32685677 PMCID:
PMC7343398 DOI:
10.1126/sciadv.aba0282]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
Age-progressive volcanism is generally accepted as the surface expression of deep-rooted mantle plumes, which are enigmatically linked with the African and Pacific large low-shear velocity provinces (LLSVPs). We present geochemical and geochronological data collected from the oldest portions of the age-progressive enriched mantle one (EMI)-type Tristan-Gough track. They are part of a 30- to 40-million year younger age-progressive hotspot track with St. Helena HIMU (high time-integrated 238U/204Pb) composition, which is also observed at the EMI-type Shona hotspot track in the southernmost Atlantic. Whereas the primary EMI-type hotspots overlie the margin of the African LLSVP, the HIMU-type hotspots are located above a central portion of the African LLSVP, reflecting a large-scale geochemical zonation. We propose that extraction of large volumes of EMI-type mantle from the margin of the LLSVP by primary plume heads triggered upwelling of HIMU material from a more internal domain of the LLSVP, forming secondary plumes.
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