Sr, Nd, Hf and Pb isotope geochemistry of Early Miocene shoshonitic lavas from the South Fiji Basin: note

ABSTRACT

We present new Sr, Nd, Hf and Pb isotope data for Early Miocene shoshonitic and high-K lavas dredged from seamounts in the South Fiji Basin, southwest Pacific Ocean. Our analyses provide a useful reference dataset for this distinctive compositional suite. The shoshonitic lavas formed in an intra-oceanic back-arc basin setting and are broadly coeval with nearby arc and back-arc basin lavas. Further work in the region will be needed before the tectonic implications of the shoshonitic and high-K lavas are fully understood.

KEYWORDS:

• SW Pacific
• South Fiji Basin
• New Zealand
• shoshonite
• isotope geochemistry
• subduction
• back-arc basins
• Miocene

Acknowledgements

We thank Nick Walker for supplying the isotope data analysed at Brown University. Earlier versions of the manuscript were improved by comments from Kevin Faure, Alex Nichols and two anonymous referees. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The data that support the findings of this study are available within the article.

Additional information

Funding

This work was supported by the French Ministry of Foreign Affairs' Fonds Pacifique and the New Zealand Foundation for Research Science and Technology.