Temporal and geochemical evolution of the Cenozoic intraplate volcanism of Zealandia.

Timm, Christian , Hoernle, Kaj , Werner, Reinhard, Hauff, Folkmar , van den Bogaard, Paul, White, James, Mortimer, Nick and Garbe-Schönberg, C.-Dieter (2010) Temporal and geochemical evolution of the Cenozoic intraplate volcanism of Zealandia. Earth-Science Reviews, 98 (1-2). pp. 38-64. DOI 10.1016/j.earscirev.2009.10.002.

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Supplementary data:

Abstract

In order to constrain better the distribution, age, geochemistry and origin of widespread Cenozoic intraplate volcanism on Zealandia, the New Zealand micro-continent, we report new 40Ar/39Ar and geochemical (major and trace element and Sr–Nd–Hf–Pb isotope) data from offshore (Chatham Rise, Campbell and Challenger Plateaus) and onland (North, South, Auckland, Campbell, Chatham and Antipodes Islands of New Zealand) volcanism on Zealandia. The samples include nephelinite, basanite through phonolite, alkali basalt through trachyte/rhyolite, and minor tholeiite and basaltic andesite, all of which have ocean island basalt (OIB)-type trace element signatures and which range in age from 64.8 to 0.17 Ma. Isotope ratios show a wide range in composition (87Sr/86Sr = 0.7027–0.7050, 143Nd/144Nd = 0.5128–0.5131, 177Hf/176Hf = 0.2829–0.2831, 206Pb/204Pb = 18.62–20.67, 207Pb/204Pb = 15.54–15.72 and 208Pb/204Pb = 38.27–40.34) with samples plotting between mid-ocean-ridge basalts (MORB) and Cretaceous New Zealand intraplate volcanic rocks.

Major characteristics of Zealandia's Cenozoic volcanism include longevity, irregular distribution and lack of age progressions in the direction of plate motion, or indeed any systematic temporal or spatial geochemical variations. We believe that these characteristics can be best explained in the context of lithospheric detachment, which causes upwelling and melting of the upper asthenospheric mantle and portions of the removed lithosphere. We propose that a large-scale seismic low-velocity anomaly, that stretches from beneath West Antarctica to Zealandia at a depth of > 600 km may represent a geochemical reservoir that has been in existence since the Cretaceous, and has been supplying the upper mantle beneath Zealandia with HIMU-type plume material throughout the Cenozoic. In addition, the sources of the Cenozoic intraplate volcanism may be at least partially derived through melting of locally detached Zealandia lower lithosphere

Document Type: Article
Keywords: intraplate volcanism, Zealandia, 40-Ar/39-Ar age dating, geochemistry, lithospheric removal, mantle plume
Research affiliation: Kiel University
OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS
Refereed: Yes
Open Access Journal?: No
Publisher: Elsevier
Projects: Future Ocean
Expeditions/Models/Experiments:
Date Deposited: 24 Feb 2010 15:02
Last Modified: 23 Sep 2019 22:41
URI: https://oceanrep.geomar.de/id/eprint/6188

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