A hidden Rodinian lithospheric keel beneath Zealandia, Earth’s newly recognized continent

R. E. Turnbull, J. J. Schwartz, M. L. Fiorentini, R. Jongens, N. J. Evans, T. Ludwig, B. J. McDonald, K. A. Klepeis

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

We present a data set of >1500 in situ O-Hf-U-Pb zircon isotope analyses that document the existence of a concealed Rodinian lithospheric keel beneath continental Zealandia. The new data reveal the presence of a distinct isotopic domain of Paleozoic–Mesozoic plutonic rocks that contain zircon characterized by anomalously low δ18O values (median = +4.1‰) and radiogenic ϵHf(t) (median = +6.1). The scale (>10,000 km2) and time span (>>250 m.y.) over which plutonic rocks with this anomalously low-δ18O signature were emplaced appear unique in a global context, especially for magmas generated and emplaced along a continental margin. Calculated crustal-residence ages (depleted mantle model, TDM) for this low-δ18O isotope domain range from 1300 to 500 Ma and are interpreted to represent melting of a Precambrian lithospheric keel that was formed and subsequently hydrothermally altered during Rodinian assembly and rifting. Recognition of a concealed Precambrian lithosphere beneath Zealandia and the uniqueness of the pervasive low-δ18O isotope domain link Zealandia to South China, providing a novel test of specific hypotheses of continental block arrangements within Rodinia.

Original languageEnglish
Pages (from-to)1009-1014
Number of pages6
JournalGeology
Volume49
Issue number8
DOIs
Publication statusPublished - 2021

Fingerprint

Dive into the research topics of 'A hidden Rodinian lithospheric keel beneath Zealandia, Earth’s newly recognized continent'. Together they form a unique fingerprint.

Cite this