|Title||A geochemical link between plume head and tail volcanism|
|Publication Type||Journal Article|
|Year of Publication||2017|
|Authors||Peters B.J, Day JMD|
|Journal||Geochemical Perspectives Letters|
Geodynamical models of mantle plumes often invoke initial, high volume plume ‘head’ magmatism, followed by lower volume plume ‘tails’. However, geochemical links between plume heads, represented by flood basalts such as the Deccan Traps, and plume tails, represented by ocean islands such as La Réunion, are ambiguous, challenging this classical view of mantle plume theory. Using Sr-Nd-Os isotope data, we demonstrate a geochemical link between archetypal plume head and tail volcanism in the Réunion hotspot. Similar plume head-tail relationships have not been definitively shown in previous geochemical studies for Réunion or other global hotspots. Such a link is enabled by use of compatible elements, such as Os, which can circumvent complexities introduced by magmatic assimilation of crust or lithosphere because these elements are scarce in crust compared to primary mantle melts. We calculate Sr-Nd-Os isotopic compositions for the Réunion primary magma and find these are identical to predictions for the Deccan primary magma. Our result provides geochemical evidence for a temporally stable mantle plume that samples a primitive reservoir associated with the African large low-shear-velocity province and with a heritage beginning at the Cretaceous-Palaeogene boundary.
A geochemical link between canonical plume head and plume tail volcanism demonstrates that mantle plumes and their mantle sources can remain physically resilient through tens of millions of years of Earth’s history. Similar geochemical links may also exist for intraplate volcanism displaying physiographic ties between ‘head’ and ‘tail’ provinces, such as the Iceland or Tristan da Cunha hotspots.