Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. In the southwest Pacific, Zealandia, the broader New Zealand micro-continent, is a 48 largely submerged continental ribbon (>3.5 × 10 6 km 2 ) formed during terrane accretion at the 49 eastern margin of Gondwana during the Phanerozoic from ca. 520-100 Ma. Present-day New 50Zealand comprises a complex collage of geological terranes (Fig. 1), of which the Cambrian 51 to Early Cretaceous basement is divided into two major provinces (Mortimer, 2004): the older 52 early Paleozoic Western Province composed of Gondwanan continental foreland, and the 53 younger (late Paleozoic to mid-Cretaceous) Eastern Province that comprises predominantly 54 deformed meta-greywackes that were accreted during a series of collisional events. These two 55 provinces are separated by the Median Batholith, a long-lived arc-root plutonic complex that 56 records the history of subduction related volcanism from the Carboniferous to Late 57Cretaceous at the Pacific margin of Gondwana (Mortimer et al., 1999 (Fig. 1). The goals of this study are, firstly, to investigate the 67 relative behaviours of the chalcophile and lithophile element isotopic systems in recording 68lithosphere formation and modification events in this off-cratonic region, and, secondly, to 69 use integrated geologic and isotopic observations to determine the origin and age of the 70 widespread radiogenic Pb "HIMU" isotopic signature observed in the SCLM and derivative 71 basalts throughout the southwest Pacific. McKenzie and O 'Nions, 1983;Meijer et al., 1990;Nakamura and Tatsumoto, 1988; Vidal and 84 Dosso, 1978), although more recently there has been a consensus that recycled ancient 85 5 oceanic lithosphere is involved in their formation (e.g. Chauvel et al., 1992;Hofmann, 2003; 86 Hofmann and White, 1982; Stracke et al., 2003; Stracke et al., 2005; Weaver, 1991; 87 Woodhead, 1996). Quantitative modelling has shown that modification of the oceanic 88 lithosphere during subduction leads to substantial Pb loss compared to both U and Th and a 89 preferential leaching of U rel...