The isotopic origin of Lord Howe Island reveals secondary mantle plume twinning in the Tasman Sea

Rogers, Angus; Flanigan, Michaela; Nebel, Oliver; Nebel-Jacobsen, Yona; Arculus, Richard; Miller, Lowell A.; Smith, I. E.; Mather, Ben; Kendrick, Mark A.; O’Neill, Hugh St. C.

doi:10.1016/j.chemgeo.2023.121374

Cited by 2 publications

(1 citation statement)

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“…The Lord Howe Seamount Chain (yellow symbols on Figure 9) is interpreted as an Oligocene‐Pliocene age‐progressive hotspot track that records the northward movement of the Australian Plate lithosphere (Mortimer et al., 2018; Rogers et al., 2023; Seton et al., 2019). Apart from the large guyots at its northern end, the Lord Howe Seamount Chain has minimal magnetic expression, with the age‐progressive seamounts marked by small positive anomalies less than 30 km across.…”

Section: Discussionmentioning

confidence: 99%

Reconnaissance Basement Geology and Tectonics of North Zealandia

Mortimer,

Williams,

Seton

et al. 2023

Tectonics

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New rock dredge samples supply key information to establish the tectonic and geological framework of the northern two‐thirds of the 95% submerged Zealandia continent. The R/V Investigator voyage IN2016T01 to the Fairway Ridge, Coral Sea, obtained poorly sorted poly‐lithologic pebbly to cobbly sandstones, well sorted fine grained sandstones, mudstones, bioclastic limestones, and basaltic lavas. Post‐cruise analytical work comprised petrography, whole rock geochemical and Sr and Nd isotopic analyses, and U‐Pb zircon, Rb‐Sr, and Ar‐Ar geochronology. A Fairway Ridge cobbly sandstone has a ∼95 Ma (early Late Cretaceous) depositional age; two biotite granite cobbles are 111 ± 1 and 128 ± 1 Ma in age, and some volcanic pebbles are also likely Early Cretaceous. Fairway Ridge basalts have intraplate alkaline chemistry and are of Late Eocene age (∼40–36 Ma). By analogy with South Zealandia, we interpret strong positive continental magnetic anomalies of North Zealandia to mainly result from Late Cretaceous to Cenozoic intraplate basalts, many of them rift‐related lavas. A new basement geological map of North Zealandia shows the position of the Mesozoic Gondwana magmatic arc axis (Median Batholith) and other major geological units. This study completes onland and offshore reconnaissance geological mapping of the entire 5 Mkm2 Zealandia continent.

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Section: Discussionmentioning

confidence: 99%