Mapping the 4D lithospheric architecture of Zealandia using zircon O and Hf isotopes in plutonic rocks

Reconnaissance Basement Geology and Tectonics of North Zealandia

“…These initial εHf values are also within the range of New Zealand detrital zircons interpreted to have been derived from the Median Batholith arc(Campbell et al, 2020) and have substantially higher initial εHf than the +2.6 median (+2.3 mean) reported for 35 zircons from the 97 Ma rhyolite at DSDP 207 (Figure1) byvan der Meer et al (2018).Challenger Plateau granite zircons have median δ 18 O = 9.2 ± 1.9‰ (n = 10), and median initial εHf = −2.5 ± 3.2 (2σ error, n = 18) (Supplemental File 7 in Supporting Information S2). The Challenger Plateau granite O and Hf isotope values overlap those established for New Zealand's Karamea Suite inTurnbull et al (2023) (Figure5h).…”

“…is +13.2 to +5.2, with the mean and median values being +8.3 and +8.1 respectively (Supplemental File 4 in Supporting Information S2). The initial εHf values are within the range of plutons emplaced in the eastern part of the Median Batholith which are derived from relatively juvenile and/or mantle-like sources with limited involvement of older crust (Figure5h,Schwartz et al, 2021;Turnbull et al, 2023). These initial εHf values are also within the range of New Zealand detrital zircons interpreted to have been derived from the Median Batholith arc(Campbell et al, 2020) and have substantially higher initial εHf than the +2.6 median (+2.3 mean) reported for 35 zircons from the 97 Ma rhyolite at DSDP 207 (Figure1) byvan der Meer et al (2018).Challenger Plateau granite zircons have median δ 18 O = 9.2 ± 1.9‰ (n = 10), and median initial εHf = −2.5 ± 3.2 (2σ error, n = 18) (Supplemental File 7 in Supporting Information S2).…”