Sampling source heterogeneities that bind the Ontong Java Nui puzzle together

Tejada, M. L. G.; Sano, Takashi; Hanyu, Takeshi; Koppers, Anthony; Nakanishi, Masao; Ishikawa, Akira; Miyazaki, Takashi; Tani, Kazuo; Shimizu, Shoka; Chang, Qing; Vaglarov, Bogdan Stefanov

doi:10.7185/gold2021.6081

Cited by 2 publications

(3 citation statements)

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“…The Hikurangi Plateau is subducting along New Zealand's Hikurangi margin at a rate of ∼20–60 mm/year (Figure 1) (Mortimer & Parkinson, 1996; Reyners et al., 2011; Wallace et al., 2004). The Plateau is thought to have formed between ∼96 and 118 Ma as part of a larger Hikurangi‐Manihiki‐Ontong Java Plateau, which would represent the largest magmatic event preserved at Earth's surface (Coffin & Eldholm, 1994; Davidson et al., 2023; Hoernle et al., 2010; Taylor, 2006; Tejada et al., 2023; Timm et al., 2011). Rifting, followed by seafloor spreading at the Osbourn Trough separated the Hikurangi and Manihiki Plateaus, with the Hikurangi Plateau drifting south before its collision and incipient subduction at the Gondwana margin, which has been linked to the cessation of subduction in this region (Billen & Stock, 2000; Davy et al., 2008a; Hoernle et al., 2020; Lonsdale, 1997; Riefstahl et al., 2020; Wood & Davy, 1994).…”

Section: Introductionmentioning

confidence: 99%

Heterogeneous Crustal Structure of the Hikurangi Plateau Revealed by SHIRE Seismic Data: Origin and Implications for Plate Boundary Tectonics

Bassett,

Fujie,

Kodaira

et al. 2023

Geophysical Research Letters

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Marine multichannel and wide‐angle seismic data constrain the distribution of seamounts, sediment cover sequence and crustal structure along a 460 km margin‐parallel transect of the Hikurangi Plateau. Seismic reflection data reveals five seamount up‐to 4.5 km high and 35–75 km wide, with heterogeneous internal velocity structure. Sediment cover decreases south‐to‐north from ∼4.5 km to ∼1–2 km. The Hikurangi Plateau crust (VP 5.5–7.5 km/s) is 11 ± 1 km thick in the south, but thins by 3–4 km further north (∼7–8 km). Gravity models constructed along two seismic lines show the reduction in crustal thickness persists further east, coinciding with a bathymetric scarp. Gravity data suggest the transition in crustal thickness may reflect spatial variability in deformation and lithospheric extension associated with plateau breakup. Variability in the thickness of subducting crust may contribute to differences in megathrust geometry, upper‐plate stress state and high‐rates of contraction and uplift along the southern Hikurangi margin.

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Section: Introductionmentioning

confidence: 99%

Heterogeneous Crustal Structure of the Hikurangi Plateau Revealed by SHIRE Seismic Data: Origin and Implications for Plate Boundary Tectonics

Bassett,

Fujie,

Kodaira

et al. 2023

Geophysical Research Letters

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“…Moreover, the latest volcanic activity occurred at the Ob‐one seamount at 8.5 Ma (Figure 5, Table S5). Volcanic activity at the oceanic plateau is known to protracted magmatism occurring over several tens of millions of years (e.g., Coffin et al., 2002; Tejada et al., 2023). For example, volcanism at the Kerguelen Plateau started at the South Kerguelen Plateau at 119 Ma and continued to the North Kerguelen Plateau in the Cenozoic (e.g., Coffin et al., 2002).…”

Section: Discussionmentioning

confidence: 99%

“…For example, volcanism at the Kerguelen Plateau started at the South Kerguelen Plateau at 119 Ma and continued to the North Kerguelen Plateau in the Cenozoic (e.g., Coffin et al., 2002). On the Ontong Java Plateau, volcanic activity began at 125 Ma and has been reported to have continued until approximately 34 Ma (e.g., Smart et al., 2019; Tejada et al., 2023). However, these plateaus are large edifices that spread over 1,000 km.…”

Section: Discussionmentioning

confidence: 99%

The Conrad Rise Revisited: Eocene to Miocene Volcanism and Its Implications for Magma Sources and Tectonic Development

Sato,

Machida,

Meyzen

et al. 2023

JGR Solid Earth

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The Conrad Rise (CR), located midway between Antarctica and the Southwest Indian Ridge (SWIR), remains one of the least explored submarine large igneous provinces (LIPs) in the Indian Ocean to date. Relying on only seafloor paleomagnetic records, early studies hypothesized that the formation of the CR occurred during the Late Cretaceous. Here, we present new geochemical and geochronological data, including Sr‒Nd‒Pb‒Hf isotopes and 40Ar/39Ar data. Our results indicate that the uppermost part of the CR (Ob and Lena seamounts) unexpectedly formed later than previously predicted, at approximately 40 Ma in an intraplate setting. Another small seamount north of the Ob seamount formed later, at 8.5 Ma. The isotopic composition of lava from the small seamount north of the Ob seamount overlaps with that commonly defined by the Indian plume component. Overall, the isotopic variations defined by the volcanic suite from the CR could be accounted for by a three‐component mixing model involving the common component, lower continental crust, and depleted mantle endmembers. The newly obtained 40Ar/39Ar ages imply that the CR volcanism might have been triggered by major regional plate reorganizations during the middle to late Eocene and the late Miocene, inducing the release of a small upwelling rising from the African large low‐velocity province.

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Sampling source heterogeneities that bind the Ontong Java Nui puzzle together

Cited by 2 publications

References 0 publications

Heterogeneous Crustal Structure of the Hikurangi Plateau Revealed by SHIRE Seismic Data: Origin and Implications for Plate Boundary Tectonics

Heterogeneous Crustal Structure of the Hikurangi Plateau Revealed by SHIRE Seismic Data: Origin and Implications for Plate Boundary Tectonics

The Conrad Rise Revisited: Eocene to Miocene Volcanism and Its Implications for Magma Sources and Tectonic Development

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