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 3 publications

(1 citation statement)

References 142 publications

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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%

Reconnaissance Basement Geology and Tectonics of North Zealandia

Mortimer,

Williams,

Seton

et al. 2023

Tectonics

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Increasing complexity in magmatic architecture of volcanoes along a waning hotspot

2023

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Pleistocene sea-level fluctuation shapes archipelago-wide population structure in the Endangered Lord Howe Island cockroachPanesthia lata

Adams,

Ewart,

Carlile

et al. 2024

Preprint

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Studies of biogeographic processes have often centred islands as model systems, yet questions remain about the role of Pleistocene sea-level fluctuations in shaping islands' biodiversity. One novel, potentially informative model system is the Lord Howe Island Group of Australia. Despite the World Heritage status of this archipelago, almost nothing is known of the biogeographic origins, evolutionary distinctiveness or genetic diversity of the ecological communities across its 28 islands. In this study, we focused on the cockroachPanesthia lata, an ecologically specialized invertebrate with one of the broadest recorded distributions of any LHIG species. To investigate the influence of Pleistocene sea-level fluctuations on LHIG fauna, we explored the phylogeography ofP. latausing single-nucleotide polymorphisms and complete mitochondrial genomes. Our analyses reveal that the lineage on the permanently isolated islet Ball's Pyramid is highly divergent from the remaining populations, while those on the episodically connected Lord Howe, Roach and Blackburn Islands experienced gene flow during the last glacial period. These results offer the first evidence that Pleistocene land bridges allowed for overland migration across the archipelago. Further, althoughP. latawas believed to have been locally extirpated by rodents on Lord Howe Island, we discovered two surviving, relict populations. We also detected high levels of inbreeding in all populations, emphasizing the need for ongoing conservation management. Finally, the combination of shallow genetic structure and low diversity suggests that genetic rescue from another island may be a viable strategy to conserve the Lord Howe Island population ofP. lata, as well as other species that have been similarly impacted by rodents.

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

Cited by 3 publications

References 142 publications

Reconnaissance Basement Geology and Tectonics of North Zealandia

Reconnaissance Basement Geology and Tectonics of North Zealandia

Increasing complexity in magmatic architecture of volcanoes along a waning hotspot

Pleistocene sea-level fluctuation shapes archipelago-wide population structure in the Endangered Lord Howe Island cockroachPanesthia lata

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