title: Louisville seamount subduction and its implication on mantle flow beneath the central Tonga-Kermadec arc.
abstract: Subduction of intraplate seamounts beneath a geochemically depleted mantle wedge provides a seldom opportunity to trace element recycling and mantle flow in subduction zones. Here we present trace element and Sr, Nd and Pb isotopic compositions of lavas from the central Tonga-Kermadec arc, west of the contemporary Louisville-Tonga trench intersection, to provide new insights into the effects of Louisville seamount subduction. Elevated (206)Pb/(204)Pb, (208)Pb/(204)Pb, (86)Sr/(87)Sr in lavas from the central Tonga-Kermadec arc front are consistent with localized input of subducted alkaline Louisville material (lavas and volcaniclastics) into sub-arc partial melts. Furthermore, absolute Pacific Plate motion models indicate an anticlockwise rotation in the subducted Louisville seamount chain that, combined with estimates of the timing of fluid release from the subducting slab, suggests primarily trench-normal mantle flow beneath the central Tonga-Kermadec arc system.
authors.affiliation: Department of Marine Geoscience, GNS Science, Lower Hutt 5040, New Zealand. c.timm@gns.cri.nz
authors.forename: Christian
authors.initials: C
authors.lastname: Timm
authors.forename: Daniel
authors.initials: D
authors.lastname: Bassett
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Graham
authors.forename: Matthew I
authors.initials: MI
authors.lastname: Leybourne
authors.forename: Cornel E J
authors.initials: CE
authors.lastname: de Ronde
authors.forename: Jon
authors.initials: J
authors.lastname: Woodhead
authors.forename: Daniel
authors.initials: D
authors.lastname: Layton-Matthews
authors.forename: Anthony B
authors.initials: AB
authors.lastname: Watts