title: How and when plume zonation appeared during the 132 Myr evolution of the Tristan Hotspot.
abstract: Increasingly, spatial geochemical zonation, present as geographically distinct, subparallel trends, is observed along hotspot tracks, such as Hawaii and the Galapagos. The origin of this zonation is currently unclear. Recently zonation was found along the last ∼70 Myr of the Tristan-Gough hotspot track. Here we present new Sr-Nd-Pb-Hf isotope data from the older parts of this hotspot track (Walvis Ridge and Rio Grande Rise) and re-evaluate published data from the Etendeka and Parana flood basalts erupted at the initiation of the hotspot track. We show that only the enriched Gough, but not the less-enriched Tristan, component is present in the earlier (70-132 Ma) history of the hotspot. Here we present a model that can explain the temporal evolution and origin of plume zonation for both the Tristan-Gough and Hawaiian hotspots, two end member types of zoned plumes, through processes taking place in the plume sources at the base of the lower mantle.
authors.affiliation: 1] GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany [2] CAU Kiel University, Institute of Geosciences, Ludewig-Meyn-Strasse 10, D-24118 Kiel, Germany.
authors.forename: Kaj
authors.initials: K
authors.lastname: Hoernle
authors.affiliation: GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany.
authors.forename: Joana
authors.initials: J
authors.lastname: Rohde
authors.affiliation: GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany.
authors.forename: Folkmar
authors.initials: F
authors.lastname: Hauff
authors.affiliation: CAU Kiel University, Institute of Geosciences, Ludewig-Meyn-Strasse 10, D-24118 Kiel, Germany.
authors.forename: Dieter
authors.initials: D
authors.lastname: Garbe-Schönberg
authors.affiliation: GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany.
authors.forename: Stephan
authors.initials: S
authors.lastname: Homrighausen
authors.affiliation: GEOMAR Helmholtz Centre for Ocean Research Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Werner
authors.affiliation: Royal Holloway, University of London, Department of Earth Sciences, Egham Hill, Egham TW20 0EX, UK.
authors.forename: Jason P
authors.initials: JP
authors.lastname: Morgan