title: Upper- and mid-mantle interaction between the Samoan plume and the Tonga-Kermadec slabs.
abstract: Mantle plumes are thought to play a key role in transferring heat from the core-mantle boundary to the lithosphere, where it can significantly influence plate tectonics. On impinging on the lithosphere at spreading ridges or in intra-plate settings, mantle plumes may generate hotspots, large igneous provinces and hence considerable dynamic topography. However, the active role of mantle plumes on subducting slabs remains poorly understood. Here we show that the stagnation at 660 km and fastest trench retreat of the Tonga slab in Southwestern Pacific are consistent with an interaction with the Samoan plume and the Hikurangi plateau. Our findings are based on comparisons between 3D anisotropic tomography images and 3D petrological-thermo-mechanical models, which self-consistently explain several unique features of the Fiji-Tonga region. We identify four possible slip systems of bridgmanite in the lower mantle that reconcile the observed seismic anisotropy beneath the Tonga slab (V(SH)>V(SV)) with thermo-mechanical calculations.
authors.affiliation: Division of Geology and Geophysics, Kangwon National University, Chuncheon, Gangwon-do 24341, South Korea.
authors.forename: Sung-Joon
authors.initials: SJ
authors.lastname: Chang
authors.affiliation: Department of Earth Sciences, University College London, London WC1E 6BT, UK.|CERIS, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal.
authors.forename: Ana M G
authors.initials: AM
authors.lastname: Ferreira
authors.affiliation: Dipartimento di Geoscienze, Università di Padova, 35131 Padova, Italy.
authors.forename: Manuele
authors.initials: M
authors.lastname: Faccenda