Volcanoes buried in Te Riu-a-Māui/Zealandia sedimentary basins

Bischoff, Alan; Barrier, Andrea; Beggs, Mac; Nicol, Andrew; Cole, Jim; Sahoo, Tusar R.

doi:10.1080/00288306.2020.1773510

Cited by 31 publications

(18 citation statements)

References 85 publications

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“…<0.5 s TwT) or no infill (Figure 5). In addition to the horst blocks, large composite volcanoes >10 km diameter also formed paleo‐highs in the Late Cretaceous post‐rift sequence which were not covered with sediment until the Latest Cretaceous or Paleocene (Figure 4b; Barrier et al., 2021; Bischoff et al., 2020).…”

Section: Results and Observationsmentioning

confidence: 99%

Sedimentary architecture of a Late Cretaceous under‐filled rift basin, Canterbury Basin, New Zealand

et al. 2021

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The Canterbury Basin in southeastern Zealandia was initiated during the late Albian (ca. 105 Ma) as a rift system, prior to the onset of seafloor spreading between Zealandia and eastern Gondwana at ca. 85 Ma. Basin‐fill architecture and sediment types have been determined from interpretation of 2D and 3D seismic‐reflection lines tied to five wells and compared to outcrop data from the literature. These data show that Cretaceous syn‐rift basin‐fill architecture was controlled by normal faulting, which produced basin and range topography that persisted for more that ca. 30 Myr after the cessation of faulting. Initial sedimentation was dominated by short drainage systems sourced from within the basin to produce alluvial fans along fault scarps, which inter‐fingered with axial‐flowing braided river conglomerates, coal measures and mudstone‐rich lake deposits in more central portions of the basins. Marine incursion of the basin from the east commenced during rifting and onset of Gondwana breakup, with maximum water depths achieved in the Oligocene. Post‐rifting, detrital sediments were mainly sourced locally from structural highs and augmented by pelagic sedimentation, which collectively draped and eventually buried most of the earlier‐formed horsts by the Early Eocene. The temporal persistence of basin and range topography reflected the low rates of erosion of horst blocks compared to the rates of fault displacement. The lack of substantial sediment input from outside of the rift basin was a key factor in the under‐filling of the Canterbury Basin. This research emphasises the key role played by sediment supply in rift basin filling. Despite an abundance of active faulting at initiation, some rift basins may fill slowly over tens of million years after rift cessation.

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Section: Results and Observationsmentioning

confidence: 99%

Sedimentary architecture of a Late Cretaceous under‐filled rift basin, Canterbury Basin, New Zealand

et al. 2021

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“…Facies models of submarine volcanoes (e.g. Allen et al, 2007;Bischoff et al, 2020) involve sector collapse and parasitic vents that can form breccias tens of km from central volcanoes.…”

Section: Dredge Sitesmentioning

confidence: 99%

The Norfolk Ridge seamounts: Eocene–Miocene volcanoes near Zealandia’s rifted continental margin

Mortimer

Patriat

Gans

et al. 2020

Australian Journal of Earth Sciences

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New age and geochemical data are used to investigate the origin of a ∼670 km-long line of eight seamount volcanoes along the western side of the Norfolk Ridge between New Caledonia and New Zealand. Altered lavas and limestones were dredged from three volcanoes during the 2015 Volcanic Evolution of South Pacific Arcs cruise of N/O l'Atalante, so a total of four, including the northernmost and southernmost, have now been directly sampled and analysed. Dating of lava and volcanic breccia clasts by Ar-Ar methods gives north-to-south ages from these sites of 31.3 ± 0.6, 33 ± 5, 21.5 ± 1.0 and 26.3 ± 0.1 Ma. These ages, along with supporting stratigraphic data on a fifth seamount from IODP borehole U1507, provisionally refute the hypotheses that the seamounts represent a southward-younging, age-progressive, intraplate volcanic chain on the Australian Plate or a subduction-related chain of restricted age range. Geochemically, the upper Eocene to lower Miocene lavas have alkaline and subalkaline basaltic compositions, and some could be shoshonitic. The location of the volcanoes along the western side of the Norfolk Ridge suggests an origin related to late Eocene and early Miocene melting near an intracontinental lithosphere-asthenosphere step. Involvement of a deep slab in petrogenesis is also possible. Key points1. Eight seamounts form a line along the Norfolk Ridge. 2. Dating and geochemistry indicate the seamount line is not a hotspot track. 3. A rift-related origin, possibly with influence by subduction, is proposed.

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“…Importantly, one of the intrusive fields is mapped close to the Toroa wellbore. This may correspond to the Toroa volcanic field interpreted by 36 . Apart from these two domains, it is also possible that there are more intrusive rocks buried within the Palaeocene and Cretaceous units.…”

Section: Resultsmentioning

confidence: 56%

“…Consequently, the seafloor mounds here are interpreted to be volcanic in origin, with fluids being derived and plumbed mainly via hydrothermal processes that post-dated Cenozoic intraplate volcanism in the GSB. Important volcanic edifices in the study area include the Tuatara volcanoes which were emplaced over 40 Myr 32 in the northern part of the study area and Pleistocene volcanoes 36 which were emplaced in the area south of the Toroa-1 well, close to the mapped seafloor mounds (Fig. 1 ).…”

Section: Discussionmentioning

confidence: 99%

“…In terms of volcanism, widespread and long-lived intraplate magmatic and volcanic activities occurred across Zealandia following the breakup of Gondwana in the Late Cretaceous and persisted throughout the Cenozoic 32 , 33 . The major intraplate volcanism in the GSB are dated Late Cretaceous, Palaeocene to Early Eocene, Late Eocene to Early Oligocene and Middle to Late Miocene 34 and are depicted by several buried volcanic features including the Late Cretaceous to Early Eocene (~ 85–45 Ma) Tuatara Volcanoes 32 , the Upper Eocene to Lower Oligocene (40–34 Ma) Waiareka–Deborah volcanoes 35 , the Early Miocene (16–11.7 Ma) Dunedin Volcano 35 and references therein, the Miocene (12–6 Ma) Akaroa and Lyttleton volcanoes 34 , 35 , the Oligocene to Early Miocene Papatowai volcanoes 36 and the Pleistocene Toroa volcanoes that have been observed in the shallow sediment column of the GSB 36 . Moreover, volcanic sequences representing Miocene volcanism have also been reported onshore 37 and from an offshore well 38 in the GSB, while Holocene volcanic activities were reported on the northern island of Zealandia 39 .…”

Section: Enigma Of Interpreting Seafloor Anomalies From Seismic Reflection Datamentioning

confidence: 99%

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Massive seafloor mounds depict potential for seafloor mineral deposits in the Great South Basin (GSB) offshore New Zealand

Omosanya

Lawal

Muhammad

et al. 2021

Sci Rep

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Seafloor mounds are enigmatic features along many continental margins and are often interpreted as gas hydrate pingoes, seep deposits, mud volcanoes, or hydrothermal mounds. When such mounds occur in basins with past volcanic activities, they have the potential to host seafloor metalliferous deposits, which is generally overlooked. Using geophysical datasets, we document the fluid plumbing systems that promoted the formation of seafloor mounds in the Great South Basin (GSB), offshore New Zealand. We also investigate these mounds as potential seafloor metalliferous deposits. Our results reveal 9 seafloor mounds (~ 137 m high) above gigantic (~ 5.4 km high) fluid escape pipes that are associated with deeper crystalline rocks. The structural make-up of the mounds, their geospatial relationships with the pipes and intrusive rocks, and geophysical properties suggest a primary volcanic or hydrothermal origin for the culpable fluids and mounds respectively. Fluids derived from deeper coal beds and shallow foraminiferal oozes in the basin constitute secondary fluid sources focused along polygonal faults and lateral flow cells. A main sub-vertical and minor lateral fluid plumbing patterns are proposed. The relationship between the mounds, pipes, underlying intrusive rocks, and upward routing of mineral-rich fluids could have implications for the formation of ore-grade mineral deposits on the seafloor in the GSB.

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Volcanoes buried in Te Riu-a-Māui/Zealandia sedimentary basins

Cited by 31 publications

References 85 publications

Sedimentary architecture of a Late Cretaceous under‐filled rift basin, Canterbury Basin, New Zealand

Sedimentary architecture of a Late Cretaceous under‐filled rift basin, Canterbury Basin, New Zealand

The Norfolk Ridge seamounts: Eocene–Miocene volcanoes near Zealandia’s rifted continental margin

Massive seafloor mounds depict potential for seafloor mineral deposits in the Great South Basin (GSB) offshore New Zealand

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