Taupo Volcanic Zone and Central Volcanic Region Backarc Structures of North Island, New Zealand

Cole, J. W.; Darby, Desmond J.; Stern, T. A.

doi:10.1007/978-1-4615-1843-3_1

Cited by 48 publications

(42 citation statements)

References 77 publications

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“…General reviews of the Taupo back-arc region are given by Cole et al (1995) and Wilson et al (1995). More specifically, the reader may consult Grindley (1960) for geology, Cole & Lewis (1981) for tectonics, Smith & Webb (1986) for seismicity, Stem (1985Stem ( ,1987 for heat flow, Darby & Meertens (1995) for geodetics, Bibby et al (1995) for resistivity and hydrothermal properties, and Smith et al (1989) for the plate tectonic significance of the TVZ.…”

Section: Introductionmentioning

confidence: 99%

Geodetic measurement of deformation in the Taupo Volcanic Zone, New Zealand: The north Taupo network revisited

Darby

Hodgkinson

Blick

2000

New Zealand Journal of Geology and Geophysics

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A previous geodetic estimate of 18 mm/yr horizontal extension for the Taupo Volcanic Zone (TVZ) immediately north of Lake Taupo for the period 1949-86 is re-examined for several reasons: this rate has not been confirmed by GPS surveys in the 1990s; newly compiled precise levelling data now allow us to estimate the extent of non-tectonic deformation attributable to the Wairakei geothermal field; and the precise levelling and lake-levelling data reveal a spatial variation in tectonic subsidence that casts doubt on the earlier assumption of homogeneous horizontal strain. We use the vertical and horizontal data to derive a Mogi point source model for the geothermal field, and this model allows us to correct the observed horizontal velocities of survey points. Statistical analysis of the corrected horizontal velocities shows that the strain across the TVZ is not homogeneous. When these factors are accounted for, an extension rate of 8 ± 2 mm/yr (1 SE) can be applicable for both 1949-86 and 1986-97. This is about half the previous estimate, which we now consider to be incorrect. The distribution of deformation differs between these periods, and the seismicity of the region shows temporal variations on a similar time-scale (decades). The extension rate is much greater than can be accounted for by seismic strain release, and the occurrence of historical earthquakes up to M = 6 indicates that a significant part of the measured extension represents seismic strain accumulation. The spatial heterogeneity of the strain partitions the region identically to that derived from geological studies of fault activity. In particular, there is a spatial concentration of extension and tilt about the Whangamata fault system.

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Section: Introductionmentioning

confidence: 99%

Geodetic measurement of deformation in the Taupo Volcanic Zone, New Zealand: The north Taupo network revisited

Darby

Hodgkinson

Blick

2000

New Zealand Journal of Geology and Geophysics

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“…Some extension may have occurred before this within the more broadly defined Central Volcanic Region immediately to the north. However, the structural, volcanic, and kinematic relationships between this area, the Taupo Volcanic Zone, and the Coromandel arc are open to debate (e.g., Stern 1987;Cole 1990;Cole et al 1995;. The northern extent of the North Island Shear Belt is uncertain, but it may not have continued beyond the continental-oceanic crustal boundary (see Gamble et al 1993), in the area roughly opposite the subduction cusp (Fig.…”

mentioning

confidence: 99%

Tectonic reconstructions of New Zealand: 40 Ma to the Present

King¹

2000

New Zealand Journal of Geology and Geophysics

340

369

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“…In either model, the MBF rhyolites, like the DPF bimodal volcanism, may reflect a rift within an ensialic island-arc setting that was outboard from both Gondwana and Laurentia. The modern Taupo Volcanic Zone in northern New Zealand, which reflects westward subduction of the Pacific Plate beneath the Australian Plate (Cole et al 1995(Cole et al , 2001, may provide a modern analogy. Magmatism within the Taupo Volcanic Zone began 8 million years ago, and so its duration is compatible with the range of magmatism recorded by the Dunn Point and McGillivray Brook formations.…”

Section: Discussionmentioning

confidence: 98%

Tectonic significance of Late Ordovician silicic magmatism, Avalon terrane, northern Antigonish Highlands, Nova Scotia ¹ This article is one of a series of papers published in CJES Special Issue: In honour of Ward Neale on the theme of Appalachian and Grenvillian geology.² Contribution to International Geological Correlation Programme (IGCP) Project 497.

2012

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Avalonia was a microcontinent during most of the Ordovician, separating the Iapetus Ocean to the north from the Rheic Ocean to the south. In the northern Antigonish Highlands, Nova Scotia, volcanic rocks (Dunn Point and McGillivray Brook formations) underlie Early Silurian -Early Devonian strata (Arisaig Group) and were thought to represent extension that heralded the development of the basin into which Arisaig Group strata were deposited. However, recent U-Pb (zircon, thermal ionization mass spectrometry) data from rhyolite in the Dunn Point Formation (DPF) yielded an age of 460.0 ± 3.4 Ma, and, here, we report a concordant age of 454.5 ± 0.7 Ma for an ignimbrite in the overlying McGillivray Brook Formation (MBF). These data confirm a ca. 10 million year gap between volcanism and onset of Arisaig Group deposition, which occurred after accretion of Avalonia to Baltica. The DPF and MBF both resemble A-type SiO2-rich magmas. The MBF has very high concentrations of Zr (745-1965 ppm), Y (65-213 ppm), Nb (57 to 185 ppm), and high Ga/Al. Several MBF samples exhibit strong LREE depletion, consistent with fractionation of LREE-bearing accessory phases. 3Ndt values for MBF (t = 455 Ma) range from +1.5 to +3.9, and overlap with DPF rhyolites that range from +2.9 to +3.7. Depleted mantle model ages for MBF and DPF samples unaffected by accessory phase fractionation are between 0.9 and 1.2 Ga and are similar to T DM values in older (Neoproterozoic, Cambrian) crustally derived felsic rocks, suggesting derivation from the lower crustal basement beneath the Antigonish Highlands. DPF and MBF rocks were probably erupted in a local extensional environment within an ensialic arc, perhaps analogous to the modern Taupo Volcanic Zone in northern New Zealand. Résumé : Avalonia était un microcontinent durant la plus grande partie de l'Ordovicien, séparant l'Océan Iapetus au nord de l'Océan Rhéique au sud. Dans la partie nord des terres hautes d'Antigonish, Nouvelle-Écosse, des roches volcaniques (formations de Dunn Point et de McGillivray Brook) reposent sous des strates datant du Silurien précoce -Dévonien précoce (Groupe d'Arisaig) et elles devaient représenter l'extension qui annonçait le développement du bassin dans lequel les strates du Groupe d'Arisaig ont été déposées. Toutefois, des données U-Pb récentes (zircon, spectrométrie de masse à ionisation thermique (TIMS)) d'une rhyolite de la Formation de Dunn Point ont indiqué un âge de 460,0 ± 3,4 Ma; nous rapportons ici un âge concordant de 454,5 ± 0,7 Ma pour une ignimbrite de la Formation de McGillivray Brook sus-jacente. Ces données confirment une lacune stratigraphique d'environ 10 millions d'années entre le volcanisme et le début de la déposition du Groupe d'Arisaig, qui a eu lieu après l'accrétion d'Avalonia à Baltica. Les formations de Dunn Point et de McGillivray Brook ressemblent toutes deux à des magmas de type A, riche en SiO 2 . La Formation de McGillivray Brook a des concentrations très élevées en Zr (745-1965 ppm), en Y (65-213 ppm), en Nb (57 à 185 ppm) et un rapport...

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Taupo Volcanic Zone and Central Volcanic Region Backarc Structures of North Island, New Zealand

Cited by 48 publications

References 77 publications

Geodetic measurement of deformation in the Taupo Volcanic Zone, New Zealand: The north Taupo network revisited

Geodetic measurement of deformation in the Taupo Volcanic Zone, New Zealand: The north Taupo network revisited

Tectonic reconstructions of New Zealand: 40 Ma to the Present

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