Cordillera Zealandia: A Mesozoic arc flare-up on the palaeo-Pacific Gondwana Margin.

ABSTRACT: Two geochemically and temporally distinct components of the Mesozoic Zealandia Cordilleran arc indicate a shift from low to high Sr/Y whole rock ratios at c. 130 Ma. Recent mapping and a reappraisal of published Sr-Nd data combined with new in-situ zircon Hf isotope analyses supports a genetic relationship between the two arc components. A reappraisal of geophysical, geochemical and P-T estimates demonstrates a doubling in thickness of the arc to at least 80 km at c. 130 Ma. Contemporaneously, magmatic addition rates shifted from ~14 km³/my per km of arc to a flare-up involving ~100 km³/my per km of arc. Excursions in Sr-Nd-Hf isotopic ratios of flare-up rocks highlight the importance of crust-dominated sources. This pattern mimics Cordilleran arcs of the Americas and

SUBMITTER: Milan LA 

PROVIDER: S-EPMC5428235 | biostudies-literature | 2017 Mar

REPOSITORIES: biostudies-literature