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Journal articles on the topic 'Calderas New Zealand'

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Author: Grafiati

Published: 10 December 2022

Last updated: 28 January 2023

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1

Cocchi, Luca, Fabio Caratori Tontini, Filippo Muccini, and Cornel E. J. de Ronde. "Magnetic Expression of Hydrothermal Systems Hosted by Submarine Calderas in Subduction Settings: Examples from the Palinuro and Brothers Volcanoes." Geosciences 11, no. 12 (December 10, 2021): 504. http://dx.doi.org/10.3390/geosciences11120504.

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Volcanism is the most widespread expression of cyclic processes of formation and/or destruction that shape the Earth’s surface. Calderas are morphological depressions resulting from the collapse of a magma chamber following large eruptions and are commonly found in subduction-related tectono-magmatic regimes, such as arc and back-arc settings. Some of the most impressive examples of seafloor hydrothermal venting occur within submarine calderas. Here, we show the results of magnetic investigations at two hydrothermally active submarine calderas, i.e., Palinuro Seamount in the Southern Tyrrhenian Sea, Italy, and Brothers volcano of the Kermadec arc, New Zealand. These volcanoes occur in different geodynamic settings but show similarities in the development of their hydrothermal systems, both of which are hosted within calderas. We present a new integrated model based on morphological, geological and magnetic data for the Palinuro caldera, and we compare this with the well-established model of Brothers caldera, highlighting the differences and common features in the geophysical expressions of both hydrothermal systems. For consistency with the results at Brothers volcano, we build a model of demagnetised areas associated with hydrothermal alteration derived from 3D inversion of magnetic data. Both these models for Brothers and Palinuro show that hydrothermal up-flow zones are strongly controlled by caldera structures which provide large-scale permeability pathways, favouring circulation of the hydrothermal fluids at depth.

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2

Barker, Simon J., Michael C. Rowe, Colin J. N. Wilson, John A. Gamble, Shane M. Rooyakkers, Richard J. Wysoczanski, Finnigan Illsley-Kemp, and Charles C. Kenworthy. "What lies beneath? Reconstructing the primitive magmas fueling voluminous silicic volcanism using olivine-hosted melt inclusions." Geology 48, no. 5 (February 27, 2020): 504–8. http://dx.doi.org/10.1130/g47422.1.

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Abstract Understanding the origins of the mantle melts that drive voluminous silicic volcanism is challenging because primitive magmas are generally trapped at depth. The central Taupō Volcanic Zone (TVZ; New Zealand) hosts an extraordinarily productive region of rhyolitic caldera volcanism. Accompanying and interspersed with the rhyolitic products, there are traces of basalt to andesite preserved as enclaves or pyroclasts in caldera eruption products and occurring as small monogenetic eruptive centers between calderas. These mafic materials contain MgO-rich olivines (Fo79–86) that host melt inclusions capturing the most primitive basaltic melts fueling the central TVZ. Olivine-hosted melt inclusion compositions associated with the caldera volcanoes (intracaldera samples) contrast with those from the nearby, mafic intercaldera monogenetic centers. Intracaldera melt inclusions from the modern caldera volcanoes of Taupō and Okataina have lower abundances of incompatible elements, reflecting distinct mantle melts. There is a direct link showing that caldera-related silicic volcanism is fueled by basaltic magmas that have resulted from higher degrees of partial melting of a more depleted mantle source, along with distinct subduction signatures. The locations and vigor of Taupō and Okataina are fundamentally related to the degree of melting and flux of basalt from the mantle, and intercaldera mafic eruptive products are thus not representative of the feeder magmas for the caldera volcanoes. Inherited olivines and their melt inclusions provide a unique “window” into the mantle dynamics that drive the active TVZ silicic magmatic systems and may present a useful approach at other volcanoes that show evidence for mafic recharge.

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3

Shane, Philip A. R., and Paul C. Froggatt. "Discriminant Function Analysis of Glass Chemistry of New Zealand and North American Tephra Deposits." Quaternary Research 41, no. 1 (January 1994): 70–81. http://dx.doi.org/10.1006/qres.1994.1008.

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AbstractMajor, trace, and rare earth element analyses of volcanic glass are used separately or in combination for correlating Quaternary tephras, often by graphical or simple comparative methods. We have taken a statistical approach using discriminant function analysis (DFA) to assess the relative discriminating power of the different elements in volcanic glasses from several tectonovolcanic provinces. We found that major oxides are powerful discriminating variables for widespread tephras from the Taupo Volcanic Zone in New Zealand and here they can be more discriminating than trace elements. A wide selection of tephras from the western United States can also be distinguished on major oxides alone, particularly those from Cascade Range volcanoes. For tephras from large intracontinental calderas, such as Long Valley or Yellowstone, REE and trace elements are more effective at discriminating than major oxides. However, tephras erupted from the Long Valley area can be distinguished on major oxide composition by DFA, despite their similar chemistry. The selection and relative significance of different elements for discriminating tephras depends on the total data set being compared, as well as the source volcano and the individual eruptive events. Caution must be exercised in the nonstatistical selection of compositional data for characterizing tephras: DFA is a more powerful and objective tool for the comparison of tephra chemistry.

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4

Eberhart-Phillips, Donna, Stephen Bannister, and Martin Reyners. "Attenuation in the mantle wedge beneath super-volcanoes of the Taupo Volcanic Zone, New Zealand." Geophysical Journal International 220, no. 1 (October 9, 2019): 703–23. http://dx.doi.org/10.1093/gji/ggz455.

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SUMMARY The Taupo Volcanic Zone has a 120-km-long section of rhyolitic volcanism, within which is a 60-km-long area of supervolcanoes. The underlying subducted slab has along-strike heterogeneity due to the Hikurangi Plateau's prior subduction history. We studied 3-D Qs (1/attenuation) using t* spectral decay from local earthquakes to 370-km depth. Selection emphasized those events with data quality to sample the low Qs mantle wedge, and Qs inversion used varied linking of nodes to obtain resolution in regions of sparse stations, and 3-D initial model. The imaged mantle wedge has a 250-km-long 150-km-wide zone of low Qs (<300) at 65–85 km depth which includes two areas of very low Qs (<120). The most pronounced low Qs feature underlies the Mangakino and Whakamaru super-eruptive calderas, with inferred melt ascending under the central rift structure. The slab is characterized by high Qs (1200–2000), with a relatively small area of reduction in Qs (<800) underlying Taupo at 65-km depth, and adjacent to the mantle wedge low Qs. This suggests abundant dehydration fluids coming off the slab at specific locations and migrating near-vertically upward to the volcanic zone. The seismicity in the subducted slab has a patch of dense seismicity underlying the rhyolitic volcanic zone, consistent with locally abundant fractures and fluid flux. The relationship between the along-arc and downdip slab heterogeneity and dehydration implies that patterns of volcanism may be strongly influenced by large initial outer rise hydration which occurred while the edge of the Hikurangi Plateau hindered subduction. A second very low Qs feature is 50-km west above the 140-km-depth slab. The distinction suggests involvement of a second dehydration peak at that depth, consistent with some numerical models.

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5

Davy, Bryan. "Seismic Reflection Profiling of the Taupo Caldera, New Zealand." Exploration Geophysics 24, no. 3-4 (September 1993): 443–54. http://dx.doi.org/10.1071/eg993443.

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6

Johnston, David, Brad Scott, Bruce Houghton, Douglas Paton, David Dowrick, Pilar Villamor, and John Savage. "Social and economic consequences of historic caldera unrest at the Taupo volcano, New Zealand and the management of future episodes of unrest." Bulletin of the New Zealand Society for Earthquake Engineering 35, no. 4 (December 31, 2002): 215–30. http://dx.doi.org/10.5459/bnzsee.35.4.215-230.

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In 1998, changes in a number of indicators (earthquakes and uplift) at two of New Zealand's active volcanic caldera systems (Okataina and Taupo) resulted in increased public, local and central government awareness and some concern about the potential significance of volcanic unrest at a caldera volcano. This paper summarises the episodes of unrest recorded at Taupo caldera since 1895. There have been four significant events (1895, 1922, 1963-64 and 1983) that have included earthquake activity and ground deformation. Caldera unrest is one of the most difficult situations the volcanological and emergency management communities will have to deal with. There is potential for adverse social and economic impacts to escalate unnecessarily, unless the event is managed appropriately. Adverse response to caldera unrest may take the form of the release of inappropriate advice, media speculation, unwarranted emergency declarations and premature cessation of economic activity and community services. A non-volcanic-crisis time provides the best opportunity to develop an understanding of the caldera unrest phenomena, and the best time to establish educational programmes, funding systems for enhanced emergency response and volcano surveillance and to develop co-ordinated contingency plans.

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7

AHYONG, SHANE T., and CAROLINE A. FARRELLY. "First Australian records of Ethusina (Crustacea: Decapoda: Ethusidae) and additional records from New Zealand." Zootaxa 4486, no. 2 (September 27, 2018): 161. http://dx.doi.org/10.11646/zootaxa.4486.2.5.

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Deep water ethusid crabs, genus Ethusina, are confirmed for the first time from Australia, with additional distribution records from New Zealand waters. Prior to the present study, Ethusina was reported from Australia on the basis of a single unidentified species from southwestern Australia. Four species are reported herein: Ethusina castro Ahyong, 2008, E. ciliacirrata Castro, 2005, E. robusta (Miers, 1886), and E. rowdeni Ahyong, 2008. Ethusina castro, previously known only from the female holotype from northern New Zealand is reported for the first time from eastern Australia, the Lord Howe Rise and Monowai Caldera, including the first known males. Ethusina ciliacirrata, described from Vanuatu, is confirmed from the Coral Sea and southwestern Australia. Ethusina rowdeni, from New Zealand, and the widespread E. robusta are recorded for the first time from Australia.

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8

Beresford, S. W., and J. W. Cole. "Kaingaroa Ignimbrite, Taupo Volcanic Zone, New Zealand: Evidence for asymmetric caldera subsidence of the Reporoa Caldera." New Zealand Journal of Geology and Geophysics 43, no. 3 (September 2000): 471–81. http://dx.doi.org/10.1080/00288306.2000.9514903.

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9

D., Milner, Cole J., and Wood C. "Asymmetric, multiple-block collapse at Rotorua Caldera, Taupo Volcanic Zone, New Zealand." Bulletin of Volcanology 64, no. 2 (April 1, 2002): 134–49. http://dx.doi.org/10.1007/s00445-001-0191-0.

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10

Cole, J. W., and K. D. Spinks. "Caldera volcanism and rift structure in the Taupo Volcanic Zone, New Zealand." Geological Society, London, Special Publications 327, no. 1 (2009): 9–29. http://dx.doi.org/10.1144/sp327.2.

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11

Ashwell, P. A., B. M. Kennedy, D. M. Gravley, F. W. von Aulock, and J. W. Cole. "Insights into caldera and regional structures and magma body distribution from lava domes at Rotorua Caldera, New Zealand." Journal of Volcanology and Geothermal Research 258 (May 2013): 187–202. http://dx.doi.org/10.1016/j.jvolgeores.2013.04.014.

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12

Illsley-Kemp, Finnigan, Pasan Herath, Calum J. Chamberlain, Konstantinos Michailos, and Colin J. N. Wilson. "A decade of earthquake activity at Taupō Volcano, New Zealand." Volcanica 5, no. 2 (October 27, 2022): 335–48. http://dx.doi.org/10.30909/vol.05.02.335348.

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Taupō, New Zealand, is an active caldera volcano that in recent times has erupted on average every ~500 years, with the latest explosive eruption in 232±10 CE. Monitoring at Taupō is challenging as there has been no eruptive activity in documented history; however, Taupō does undergo periods of unrest on roughly a decadal timescale, such as in 2019. Key to identifying these unrest periods is understanding what represents 'normal' inter-unrest activity. In this study, we generate an earthquake catalogue for Taupō for 2010–2019 inclusive, consisting of 46,481 earthquakes. This shows that the Taupō region has background earthquake rates of 50–200 earthquakes per month and the 2019 unrest episode was preceded by an exponential increase in earthquake rate. We also show that when attenuation is accounted for there is no evidence for low-frequency earthquakes at Taupō, and that this is an important consideration for volcano monitoring and determining the presence of significant magma movement.

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13

Acosta Hospitaleche, Carolina, Martin Chavez, and Omar Fritis. "Fossil penguins (Pygoscelis calderensis sp. nov.) in the Bahía Inglesa Formation (Middle Miocene-Pliocene), Chile." Andean Geology 33, no. 2 (June 30, 2010): 327. http://dx.doi.org/10.5027/andgeov33n2-a06.

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Three new penguin skulls (Spheniscidae), assigned to the new species Pygoscelis calderensis sp. nov. from the Bahía Inglesa Formation of Middle Miocene-Pliocene age located south of Caldera on the coast of the III Región de Atacama, Chile (27°00'S, 70°45'W to 28°00', 71°00'W), are described. This finding broadens the geographic and chronologic distribution of the genus, constituting its most northern record. Before the present work, the genus was known from the Late Pliocene of New Zealand. This record, together with other faunistic evidences, suggests the existence of periods or cold oceanic currents during the Neogene.

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14

Hunt, T. M. "Gravity anomalies, caldera structure, and subsurface geology in the Rotorua area, New Zealand." Geothermics 21, no. 1-2 (February 1992): 65–74. http://dx.doi.org/10.1016/0375-6505(92)90068-k.

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15

Lamarche, Geoffroy. "Seismic reflection survey in the geothermal field of the rotorua caldera, new zealand." Geothermics 21, no. 1-2 (February 1992): 109–19. http://dx.doi.org/10.1016/0375-6505(92)90072-h.

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16

Belt, Karen. "Novel Scientific Evidence and Judicial "Gatekeeping": R v Calder and Daubert v Merrell Dow Pharmaceuticals Compared." Victoria University of Wellington Law Review 28, no. 2 (May 1, 1998): 399. http://dx.doi.org/10.26686/vuwlr.v28i2.6076.

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This article examines the approach of the High Court to the admissibility of novel scientific expert evidence in R v Calder (Unreported, 12 April 1995, High Court, Christchurch Registry, T 154/94). In Calder, Tipping J establishes a "gatekeeping" role for judges which requires them to test novel scientific evidence for relevance and reliability. The article compares that approach with the approach taken by the United States Supreme Court in Daubert v Merrell Dow Pharmaceuticals (1993) 125 L Ed 2d 469. The implications of such a test are considered. Although the Court of Appeal has not considered the issues raised in Calder, the article concludes that the approach is the most suitable one for New Zealand.

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17

de Ronde, Cornel E. J., Susan E. Humphris, Tobias W. Höfig, and Agnes G. Reyes. "Critical role of caldera collapse in the formation of seafloor mineralization: The case of Brothers volcano." Geology 47, no. 8 (June 6, 2019): 762–66. http://dx.doi.org/10.1130/g46047.1.

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Abstract Hydrothermal systems hosted by submarine arc volcanoes commonly include a large component of magmatic fluid. The high Cu-Au contents and strongly acidic fluids in these systems are similar to those that formed in the shallow parts of some porphyry copper and epithermal gold deposits mined today on land. Two main types of hydrothermal systems occur along the submarine portion of the Kermadec arc (offshore New Zealand): magmatically influenced and seawater-dominated systems. Brothers volcano hosts both types. Here, we report results from a series of drill holes cored by the International Ocean Discovery Program into these two types of hydrothermal systems. We show that the extent of hydrothermal alteration of the host dacitic volcaniclastics and lavas reflects primary lithological porosity and contrasting spatial and temporal contributions of magmatic fluid, hydrothermal fluid, and seawater. We present a two-step model that links the changes in hydrothermal fluid regime to the evolution of the volcano caldera. Initial hydrothermal activity, prior to caldera formation, was dominated by magmatic gases and hypersaline brines. The former mixed with seawater as they ascended toward the seafloor, and the latter remained sequestered in the subsurface. Following caldera collapse, seawater infiltrated the volcano through fault-controlled permeability, interacted with wall rock and the segregated brines, and transported associated metals toward the seafloor and formed Cu-Zn-Au–rich chimneys on the caldera walls and rim, a process continuing to the present day. This two-step process may be common in submarine arc caldera volcanoes that host volcanogenic massive sulfide deposits, and it is particularly efficient at focusing mineralization at, or near, the seafloor.

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18

Davy, B. W., and T. G. Caldwell. "Gravity, magnetic and seismic surveys of the caldera complex, Lake Taupo, North Island, New Zealand." Journal of Volcanology and Geothermal Research 81, no. 1-2 (April 1998): 69–89. http://dx.doi.org/10.1016/s0377-0273(97)00074-7.

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19

Spinks, Karl D., Valerio Acocella, Jim W. Cole, and Kari N. Bassett. "Structural control of volcanism and caldera development in the transtensional Taupo Volcanic Zone, New Zealand." Journal of Volcanology and Geothermal Research 144, no. 1-4 (June 2005): 7–22. http://dx.doi.org/10.1016/j.jvolgeores.2004.11.014.

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20

Smith, N., J. Cassidy, C. A. Locke, J. L. Mauk, and A. B. Christie. "The role of regional-scale faults in controlling a trapdoor caldera, Coromandel Peninsula, New Zealand." Journal of Volcanology and Geothermal Research 149, no. 3-4 (January 2006): 312–28. http://dx.doi.org/10.1016/j.jvolgeores.2005.09.005.

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21

Smith, Robyn C. M. "Post-eruption sedimentation on the margin of a caldera lake, Taupo Volcanic Centre, New Zealand." Sedimentary Geology 74, no. 1-4 (November 1991): 89–138. http://dx.doi.org/10.1016/0037-0738(91)90036-d.

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22

WEBBER, W. RICHARD. "A new species of Alvinocaris (Crustacea: Decapoda: Alvinocarididae) and new records of alvinocaridids from hydrothermal vents north of New Zealand." Zootaxa 444, no. 1 (March 1, 2004): 1. http://dx.doi.org/10.11646/zootaxa.444.1.1.

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Alvinocaris niwa n. sp. is described from hydrothermal vents at the Brothers Caldera and Rumble V Seamount on the southern Kermadec Ridge, midway between the Kermadec Islands and Bay of Plenty, New Zealand. Four hundred specimens of Alvinocaris longirostris Kikuchi & Ohta, 1995, described from Japan, are recorded at the Brothers. The presence of a possible third Alvinocaris at Rumble V and one or two species of Chorocaris at Brothers are also reported. Eighty-eight specimens of A. niwa and 41 of A. longirostris were measured and examined to assess morphological variation. Morphological characters used to distinguish alvinocaridids are shown to be highly variable. Pairwise correlations with carapace length indicate that numbers of teeth, spines and setae are generally not related to shrimp size. Descriptions based on small numbers of specimens are thus questionable. The new species is characterised by: short rostrum; paired sternal spines on abdominal somites I III; long stylocerite and robust distolateral spine on the antennular proximal segment, with a subterminal spine; two ventral spines on antennal basal segment; row of spines on distal segment of maxilliped III; and two rows of spines on flexor surface of P3 P5 dactyls. It is the shallowest alvinocaridid yet discovered and also inhabits the greatest depth range, at over 700 m.

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23

Charlier, B. L. A., and C. J. N. Wilson. "Chronology and Evolution of Caldera-forming and Post-caldera Magma Systems at Okataina Volcano, New Zealand from Zircon U–Th Model-age Spectra." Journal of Petrology 51, no. 5 (April 16, 2010): 1121–41. http://dx.doi.org/10.1093/petrology/egq015.

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24

Davy, Bryan, and Hugh Bibby. "Seismic reflection imaging of the Haraharo Caldera boundary beneath Lake Tarawera, Okataina Volcanic Centre, New Zealand." New Zealand Journal of Geology and Geophysics 48, no. 1 (March 2005): 153–66. http://dx.doi.org/10.1080/00288306.2005.9515106.

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25

Seebeck, H., A. Nicol, T. A. Stern, H. M. Bibby, and V. Stagpoole. "Fault controls on the geometry and location of the Okataina Caldera, Taupo Volcanic Zone, New Zealand." Journal of Volcanology and Geothermal Research 190, no. 1-2 (February 2010): 136–51. http://dx.doi.org/10.1016/j.jvolgeores.2009.04.011.

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26

Henry, Matt. "The settler's plot: how stories take place in New Zealand - By Alex Calder." New Zealand Geographer 68, no. 1 (April 2012): 71–72. http://dx.doi.org/10.1111/j.1745-7939.2012.01222_2.x.

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27

Beresford, S. W., and J. W. Cole. "Kawerau Ignimbrite: A 0.24 Ma ignimbrite erupted from the Okataina caldera complex, Taupo Volcanic Zone, New Zealand." New Zealand Journal of Geology and Geophysics 43, no. 1 (March 2000): 109–15. http://dx.doi.org/10.1080/00288306.2000.9514873.

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28

Suzuki, Yohey, Masae Suzuki, Shinji Tsuchida, Ken Takai, Koki Horikoshi, Alan J. Southward, William A. Newman, and Toshiyuki Yamaguchi. "Molecular investigations of the stalked barnacleVulcanolepas osheaiand the epibiotic bacteria from the Brothers Caldera, Kermadec Arc, New Zealand." Journal of the Marine Biological Association of the United Kingdom 89, no. 4 (May 15, 2009): 727–33. http://dx.doi.org/10.1017/s0025315409000459.

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The hydrothermal-vent barnacleVulcanolepas osheaiof the subfamily Neolepadinae is one of the most conspicuous organisms at the Brothers Caldera, south Kermadec Arc, New Zealand. Like a neolepad species found in the Lau Basin,V. osheaiharbours filamentous bacteria on its elongated cirral setae. To define the phylogenetic affiliation of the epibiotic bacteria and the nutrition of the barnacle host, we conducted molecular phylogenetic and isotopic analyses. Analysis of 16S rRNA gene sequences of microbial communities on the cirral setae showed that among 91 bacterial sequences investigated, 28 sequences were related to the ɛ-proteobacterial endosymbiont ofAlviniconchaaff.hessleri; 11 sequences were related to the epibiont of the bresiliid shrimpRimicarisexoculata. Fluorescencein situhybridization showed that in contrary to results from the 16S rRNA gene-sequence library, approximately 80% of the filamentous bacteria hybridized with a probe targeting the sequences related to the epibiont of the bresiliid shrimpR. exoculata. The fatty-acid profiles of the filamentous bacteria and the host barnacle both contained high levels of monounsaturated C16and C18fatty acids, and the carbon isotopic compositions of the biomass and monounsaturated C16and C18fatty acids of both the bacteria and barnacle were nearly identical. This would suggest that the nutrition of the barnacle is highly dependent on bacteria thriving around the barnacle, including the epibiotic bacteria.

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29

Hamling, Ian J., Geoff Kilgour, Sigrun Hreinsdóttir, Edward Bertrand, and Stephen Bannister. "Estimating the distribution of melt beneath the Okataina Caldera, New Zealand: An integrated approach using geodesy, seismology and magnetotellurics." Journal of Volcanology and Geothermal Research 426 (June 2022): 107549. http://dx.doi.org/10.1016/j.jvolgeores.2022.107549.

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30

Milner, D. M., J. W. Cole, and C. P. Wood. "Mamaku Ignimbrite: a caldera-forming ignimbrite erupted from a compositionally zoned magma chamber in Taupo Volcanic Zone, New Zealand." Journal of Volcanology and Geothermal Research 122, no. 3-4 (April 2003): 243–64. http://dx.doi.org/10.1016/s0377-0273(02)00504-8.

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31

Cole, J. W., S. J. A. Brown, R. M. Burt, S. W. Beresford, and C. J. N. Wilson. "Lithic types in ignimbrites as a guide to the evolution of a caldera complex, Taupo volcanic centre, New Zealand." Journal of Volcanology and Geothermal Research 80, no. 3-4 (February 1998): 217–37. http://dx.doi.org/10.1016/s0377-0273(97)00045-0.

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32

Caratori Tontini, F., M. A. Tivey, C. E. J. Ronde, and S. E. Humphris. "Heat Flow and Near‐Seafloor Magnetic Anomalies Highlight Hydrothermal Circulation at Brothers Volcano Caldera, Southern Kermadec Arc, New Zealand." Geophysical Research Letters 46, no. 14 (July 28, 2019): 8252–60. http://dx.doi.org/10.1029/2019gl083517.

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33

Hodgson, K. A., and I. A. Nairn. "The c. AD 1315 syn‐eruption and AD 1904 post‐eruption breakout floods from Lake Tarawera, Haroharo caldera, North Island, New Zealand." New Zealand Journal of Geology and Geophysics 48, no. 3 (September 2005): 491–506. http://dx.doi.org/10.1080/00288306.2005.9515128.

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34

Briggs, R. M., and B. W. J. Fulton. "Volcanism, structure, and petrology of the Whiritoa-Whangamata coastal section, Coromandel Volcanic Zone, New Zealand: Facies model evidence for the Tunaiti caldera." New Zealand Journal of Geology and Geophysics 33, no. 4 (October 1990): 623–33. http://dx.doi.org/10.1080/00288306.1990.10421380.

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35

Smith, Victoria, Phil Shane, and Ian Nairn. "Insights into silicic melt generation using plagioclase, quartz and melt inclusions from the caldera-forming Rotoiti eruption, Taupo volcanic zone, New Zealand." Contributions to Mineralogy and Petrology 160, no. 6 (April 23, 2010): 951–71. http://dx.doi.org/10.1007/s00410-010-0516-0.

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36

Kósik, Szabolcs, Károly Németh, Martin Danišík, Jonathan N. Procter, Axel K. Schmitt, Bjarne Friedrichs, and Robert B. Stewart. "Shallow subaqueous to emergent intra-caldera silicic volcanism of the Motuoapa Peninsula, Taupo Volcanic Zone, New Zealand – New constraints from geologic mapping, sedimentology and zircon geochronology." Journal of Volcanology and Geothermal Research 411 (March 2021): 107180. http://dx.doi.org/10.1016/j.jvolgeores.2021.107180.

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37

Cole, J. W., C. D. Deering, R. M. Burt, S. Sewell, P. A. R. Shane, and N. E. Matthews. "Okataina Volcanic Centre, Taupo Volcanic Zone, New Zealand: A review of volcanism and synchronous pluton development in an active, dominantly silicic caldera system." Earth-Science Reviews 128 (January 2014): 1–17. http://dx.doi.org/10.1016/j.earscirev.2013.10.008.

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38

Hopkins, Jenni L., Janine E. Bidmead, David J. Lowe, Richard J. Wysoczanski, Bradley J. Pillans, Luisa Ashworth, Andrew B. H. Rees, and Fiona Tuckett. "TephraNZ: a major- and trace-element reference dataset for glass-shard analyses from prominent Quaternary rhyolitic tephras in New Zealand and implications for correlation." Geochronology 3, no. 2 (September 23, 2021): 465–504. http://dx.doi.org/10.5194/gchron-3-465-2021.

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Abstract. Although analyses of tephra-derived glass shards have been undertaken in New Zealand for nearly four decades (pioneered by Paul Froggatt), our study is the first to systematically develop a formal, comprehensive, open-access reference dataset of glass-shard compositions for New Zealand tephras. These data will provide an important reference tool for future studies to identify and correlate tephra deposits and for associated petrological and magma-related studies within New Zealand and beyond. Here we present the foundation dataset for TephraNZ, an open-access reference dataset for selected tephra deposits in New Zealand. Prominent, rhyolitic, tephra deposits from the Quaternary were identified, with sample collection targeting original type sites or reference locations where the tephra's identification is unequivocally known based on independent dating and/or mineralogical techniques. Glass shards were extracted from the tephra deposits, and major- and trace-element geochemical compositions were determined. We discuss in detail the data reduction process used to obtain the results and propose that future studies follow a similar protocol in order to gain comparable data. The dataset contains analyses of glass shards from 23 proximal and 27 distal tephra samples characterising 45 eruptive episodes ranging from Kaharoa (636 ± 12 cal yr BP) to the Hikuroa Pumice member (2.0 ± 0.6 Ma) from six or more caldera sources, most from the central Taupō Volcanic Zone. We report 1385 major-element analyses obtained by electron microprobe (EMPA), and 590 trace-element analyses obtained by laser ablation (LA)-ICP-MS, on individual glass shards. Using principal component analysis (PCA), Euclidean similarity coefficients, and geochemical investigation, we show that chemical compositions of glass shards from individual eruptions are commonly distinguished by major elements, especially CaO, TiO2, K2O, and FeOtt (Na2O+K2O and SiO2/K2O), but not always. For those tephras with similar glass major-element signatures, some can be distinguished using trace elements (e.g. HFSEs: Zr, Hf, Nb; LILE: Ba, Rb; REE: Eu, Tm, Dy, Y, Tb, Gd, Er, Ho, Yb, Sm) and trace-element ratios (e.g. LILE/HFSE: Ba/Th, Ba/Zr, Rb/Zr; HFSE/HREE: Zr/Y, Zr/Yb, Hf/Y; LREE/HREE: La/Yb, Ce/Yb). Geochemistry alone cannot be used to distinguish between glass shards from the following tephra groups: Taupō (Unit Y in the post-Ōruanui eruption sequence of Taupō volcano) and Waimihia (Unit S); Poronui (Unit C) and Karapiti (Unit B); Rotorua and Rerewhakaaitu; and Kawakawa/Ōruanui, and Okaia. Other characteristics, including stratigraphic relationships and age, can be used to separate and distinguish all of these otherwise-similar tephra deposits except Poronui and Karapiti. Bimodality caused by K2O variability is newly identified in Poihipi and Tahuna tephras. Using glass-shard compositions, tephra sourced from Taupō Volcanic Centre (TVC) and Mangakino Volcanic Centre (MgVC) can be separated using bivariate plots of SiO2/K2O vs. Na2O+K2O. Glass shards from tephras derived from Kapenga Volcanic Centre, Rotorua Volcanic Centre, and Whakamaru Volcanic Centre have similar major- and trace-element chemical compositions to those from the MgVC, but they can overlap with glass analyses from tephras from Taupō and Okataina volcanic centres. Specific trace elements and trace-element ratios have lower variability than the heterogeneous major-element and bimodal signatures, making them easier to fingerprint geochemically.

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Shane, Phil, Victoria C. Smith, and Ian A. Nairn. "High temperature rhyodacites of the 36 ka Hauparu pyroclastic eruption, Okataina Volcanic Centre, New Zealand: Change in a silicic magmatic system following caldera collapse." Journal of Volcanology and Geothermal Research 147, no. 3-4 (October 2005): 357–76. http://dx.doi.org/10.1016/j.jvolgeores.2005.04.015.

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Smith, Victoria, Phil Shane, and Ian Nairn. "Using quartz and plagioclase to gain insight into chemical and thermal evolution of the Rotoiti magma prior to the caldera-forming eruption ±55 ka, New Zealand." IOP Conference Series: Earth and Environmental Science 3 (October 1, 2008): 012016. http://dx.doi.org/10.1088/1755-1307/3/1/012016.

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Burt, R. M., S. J. A. Brown, J. W. Cole, D. Shelley, and T. E. Waight. "Glass-bearing plutonic fragments from ignimbrites of the Okataina caldera complex, Taupo Volcanic Zone, New Zealand: remnants of a partially molten intrusion associated with preceding eruptions." Journal of Volcanology and Geothermal Research 84, no. 3-4 (September 1998): 209–37. http://dx.doi.org/10.1016/s0377-0273(98)00039-0.

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42

Reysenbach, Anna-Louise, Emily St. John, Jennifer Meneghin, Gilberto E. Flores, Mircea Podar, Nina Dombrowski, Anja Spang, et al. "Complex subsurface hydrothermal fluid mixing at a submarine arc volcano supports distinct and highly diverse microbial communities." Proceedings of the National Academy of Sciences 117, no. 51 (December 4, 2020): 32627–38. http://dx.doi.org/10.1073/pnas.2019021117.

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Hydrothermally active submarine volcanoes are mineral-rich biological oases contributing significantly to chemical fluxes in the deep sea, yet little is known about the microbial communities inhabiting these systems. Here we investigate the diversity of microbial life in hydrothermal deposits and their metagenomics-inferred physiology in light of the geological history and resulting hydrothermal fluid paths in the subsurface of Brothers submarine volcano north of New Zealand on the southern Kermadec arc. From metagenome-assembled genomes we identified over 90 putative bacterial and archaeal genomic families and nearly 300 previously unknown genera, many potentially endemic to this submarine volcanic environment. While magmatically influenced hydrothermal systems on the volcanic resurgent cones of Brothers volcano harbor communities of thermoacidophiles and diverse members of the superphylum “DPANN,” two distinct communities are associated with the caldera wall, likely shaped by two different types of hydrothermal circulation. The communities whose phylogenetic diversity primarily aligns with that of the cone sites and magmatically influenced hydrothermal systems elsewhere are characterized predominately by anaerobic metabolisms. These populations are probably maintained by fluids with greater magmatic inputs that have interacted with different (deeper) previously altered mineral assemblages. However, proximal (a few meters distant) communities with gene-inferred aerobic, microaerophilic, and anaerobic metabolisms are likely supported by shallower seawater-dominated circulation. Furthermore, mixing of fluids from these two distinct hydrothermal circulation systems may have an underlying imprint on the high microbial phylogenomic diversity. Collectively our results highlight the importance of considering geologic evolution and history of subsurface processes in studying microbial colonization and community dynamics in volcanic environments.

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Zellmer, Georg F., Jun-Ichi Kimura, Claudine H. Stirling, Gert Lube, Phil A. Shane, and Yoshiyuki Iizuka. "Genesis of Recent Mafic Magmatism in the Taupo Volcanic Zone, New Zealand: Insights into the Birth and Death of Very Large Volume Rhyolitic Systems?" Journal of Petrology 61, no. 2 (February 2020). http://dx.doi.org/10.1093/petrology/egaa027.

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Abstract Mafic magmatism of the rifting Taupo Volcanic Zone (TVZ) of the North Island, New Zealand, is volumetrically minor, but is thought to tap the material that provides the heat source for voluminous rhyolite production through partial melting of the crust, which ultimately results in very large volume explosive eruptions. We have studied the major and trace element chemistry of 14 mafic samples from across the entire TVZ, and the U isotopic composition of whole-rocks, groundmasses and separates of mafic mineral phases from a selection of nine samples (with the remaining five too sparsely phyric for mineral separation). Some minerals yield significant 234U enrichments despite groundmass and whole-rock close to 238U–234U secular equilibrium, pointing to uptake of variably hydrothermally altered antecrystic minerals prior to the eruption of originally sparsely phyric to aphyric mafic magmas. However, incompatible trace element patterns indicate that there are three chemically distinct groups of samples, and that samples may be used to derive primary melt compositions. We employ the latest version of the Arc Basalt Simulator (ABS5) to forward model these compositions, deriving mantle source parameters including mantle fertility, slab liquid flux, mantle volatile content, degree of melting, and P–T conditions of melt segregation. We show that mafic rocks erupted in areas of old, now inactive calderas constitute low-degree, deep melts, whereas those in areas of active caldera-volcanism are high-degree partial melts segregated from a less depleted source at an intermediate depth. Finally, high-Mg basaltic andesites erupted in the SW and NE of the TVZ point to a fertile, shallow mantle source. Our data are consistent with a petrogenetic model in which mantle melting is dominated by decompression, rather than fluid fluxing, and progresses from shallow to deeper levels with time. Melt volumes initially increase to a tipping point, at which large-scale crustal melting and caldera volcanism become prominent, and then decrease owing to progressive depletion of the mantle wedge by melting, resulting in the dearth of heat provided and eventual cessation of very large volume rhyolitic volcanism. ABS5 modelling therefore supports the notion of a direct link between the chemistry of recently erupted mafic magmas and the long-term activity and evolution of rhyolitic volcanism in the TVZ.

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Martin, Andrew J., John W. Jamieson, Cornel E. J. de Ronde, Susan E. Humphris, Stephen Roberts, Christopher J. MacLeod, Yuanfeng Cai, Chao Zhang, Lucy E. M. Schlicht, and Tatsuo Nozaki. "Hydrothermal Alteration Within the Brothers Submarine Arc Volcano, Kermadec Arc, New Zealand." Economic Geology, July 13, 2022. http://dx.doi.org/10.5382/econgeo.4962.

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Abstract The hydrothermally active Brothers volcano on the Kermadec arc, New Zealand, hosts two geochemically distinct hydrothermal systems within a single caldera. At the NW Caldera, metal-sulfide–rich black smoker spires form on the caldera wall. In contrast, Fe-rich crusts and native sulfur-rich chimneys occur at the resurgent central Upper Cone. Previous studies have revealed that the contrasting styles of hydrothermalism relate to the variable contribution of magmatic volatiles between these sites, with the Upper Cone experiencing relatively higher amounts of magmatic volatile influx. We present results of a study of the hydrothermal alteration within Brothers volcano based on core samples to a depth of 453 meters below sea floor (mbsf) from both the Upper Cone (Site U5128) and NW Caldera sites (Site U1527 and U1530), drilled by the International Ocean Discovery Program. The dacitic to rhyolitic breccias that make up the volcano are variably altered to alteration mineral assemblages consisting of chlorite + quartz, illite + pyrophyllite, natroalunite + pyrophyllite, and smectite-rich assemblages. The distribution and textures of the alteration minerals within and between different sites at Brothers volcano reflect variations in temperature, fluid pH, and fluid flux. We find that natroalunite only occurs at the Upper Cone, while alteration at the NW Caldera is more diverse and is characterized by both chlorite and pyrophyllite-rich alteration, indicating that seawater-derived hydrothermal fluids overprinted earlier magmatic volatile-influenced alteration. Our data indicate that in magmatic volatile-dominated systems, the alteration mineralogy transitions from natroalunite to pyrophyllite-rich with increasing age or maturity. This is accompanied by a distinct change in sample texture from dominantly bleached selvages to a more massive, equigranular texture.

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Lee, Hyun Joo, Jung Hun Seo, Cornel E. J. de Ronde, and Christoph A. Heinrich. "Fluid Inclusion Evidence for Subseafloor Magmatic-Hydrothermal Processes at Brothers Volcano, Kermadec Arc, New Zealand." Economic Geology, April 20, 2022. http://dx.doi.org/10.5382/econgeo.4884.

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Abstract Brothers volcano is a submarine dacitic caldera located on the southern Kermadec arc. It is host to the NW Caldera vent field (Site U1530 and Hole U1530A) that locally discharges more focused, metal-rich fluids, and the Upper Cone hydrothermal vent field (Site U1528 and Hole U1528D) that discharges predominantly diffuse, acidic fluids (pH 1.9). These two active vent sites were drilled in 2018 by the International Ocean Discovery Program (IODP) Expedition 376. Fluid inclusions hosted in anhydrite, quartz, barite, and alunite recovered from drill core samples were studied by microthermometry, Raman spectroscopy, and laser ablation-inductively coupled plasma-mass spectrometery (LA-ICP-MS) to obtain detailed depth profiles of temperature, salinity, and composition of the hydrothermal fluids. These analyses allow for a better understanding of complex hydrothermal processes such as phase separation and an assessment of magmatic-hydrothermal contributions while making reference to the dynamics of the deep hydrothermal fluid that rises beneath the hydrothermal vents at Brothers. The fluid inclusions have homogenization temperatures (Th) ranging from 149° to 358°C and salinities between 0.7 and 10.0 wt % NaCl equiv at the Upper Cone site and Th of 254° to 394°C and salinities between 0.7 and 9.8 wt % NaCl equiv at the NW Caldera site. Microthermometry of fluid inclusions hosted in sulfate minerals from the NW Caldera site indicates subseafloor mixing between hydrothermal fluids and seawater. The enrichment of vapor-partitioning elements B and As in the fluid inclusions suggests phase separation subseafloor, which may be accompanied by halite dissolution and precipitation. Highly diverging Cl/Br values provide indirect evidence for halite dissolution that occurred via subseafloor convection of seawater. Petrographic observations made of the fluid inclusions, such as the recognition of combined liquid-rich and vapor-rich “boiling assemblages” and the occurrence of CO2 in the inclusions, indicate phase separation of hydrothermal fluids. The CO2 and the content of trace elements and metals in the fluid inclusions are significantly higher than that reported for Brothers vent fluid values, which reflects a magmatic-hydrothermal contribution. At the NW Caldera site, relatively high-temperature hydrothermal fluids with high Cu (max 560 ppm) and Zn (max 740 ppm) mixed with seawater before discharging at the sea floor. Depth profiles of the fluid inclusion data identify a few specific depths of channelized (focused) hydrothermal fluid flow. We suggest that the hydrothermal fluids are mainly focused along lithological contacts which act as permeable pathways, enhancing subseafloor hydrothermal fluid flow.

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Sas, May, Phil Shane, Takeshi Kuritani, Georg F. Zellmer, Adam J. R. Kent, and Mitsuhiro Nakagawa. "Mush, melts and metasediments: A history of rhyolites from the Okataina Volcanic Centre, New Zealand, as captured in plagioclase." Journal of Petrology, May 1, 2021. http://dx.doi.org/10.1093/petrology/egab038.

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Abstract The Okataina Volcanic Centre (OVC), located in the Taupo Volcanic Zone, New Zealand, is a dominantly rhyolitic magmatic system in an arc setting, where eruptions are thought to be driven by mafic recharge. Here, Sr-Pb isotopes, and compositional and textural variations in plagioclase phenocrysts from ten rhyolitic deposits (two caldera, one immediately post-caldera, four intra-caldera, and three extra-caldera) are used to investigate the OVC magmatic system and identify the sources and assimilants within this diverse mush zone. Plagioclase interiors exhibit normal and reverse zoning, and are commonly in disequilibrium with their accompanying glass, melt inclusions, and whole rock compositions. This indicates that the crystals nucleated in melts that differed from their carrier magma. In contrast, the outermost rims of crystals exhibit normal zoning that is compositionally consistent with growth in cooling and fractionating melts just prior to eruption. At the intra-crystal-scale, the total suite of 87Sr/86Sr ratios are highly variable (0.7042–0.7065 ± 0.0004 average 2se), however, the majority (95%) of the crystals are internally homogeneous within error. At whole-crystal-scale (where better precision is obtained) 87Sr/86Sr ratios are much more homogeneous (0.70512–0.70543 ± 0.00001 average 2se) and overlap with their host whole rock Sr isotopic ratios. Whole-crystal Pb isotopic ratios also largely overlap with whole rock Pb ratios. The plagioclase and whole rock isotopic compositions indicate significant crustal assimilation (≥20%) of Torlesse-like metasediments (local basement rock) by a depleted mid-ocean ridge mantle magma source, and Pb isotopes require variable fluid-dominant subduction flux. The new data support previous petrogenetic models for OVC magmas that require crystal growth in compositionally and thermally distinct magmas within a complex of disconnected melt-and-mush reservoirs. These reservoirs were rejuvenated by underplating basaltic magmas that serve as an eruption trigger. However, the outermost rims of the plagioclase imply interaction between silicic melts and eruption-triggering mafic influx is largely limited to heat and volatile transfer, and results in rapid mobilization and syn-eruption mixing of rhyolitic melts. Finally, relatively uniform isotopic compositions of plagioclase indicate balanced contributions from the crust and mantle over the lifespan of the OVC magmatic system.

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Steer, Philip. "Alex Calder. The Settler’s Plot: How Stories Take Place in New Zealand." Journal of New Zealand Studies, no. 10 (January 1, 2011). http://dx.doi.org/10.26686/jnzs.v0i10.1173.

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48

Stucker, V. K., C. E. J. de Ronde, K. J. Laurence, and A. M. Phillips. "Rare Time Series of Hydrothermal Fluids for a Submarine Volcano: 14 Years of Vent Fluid Compositions for Brothers Volcano, Kermadec Arc New Zealand." Economic Geology, June 24, 2022. http://dx.doi.org/10.5382/econgeo.4922.

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Abstract Hydrothermal vent fluids from Brothers submarine arc volcano were previously collected in 2004, 2005, and 2017. We present new data from 2018 along with a unique time series of a submarine volcano hosting two distinct types of hydrothermal venting to better understand subsurface processes and how they evolve over time. Samples were collected from known venting locations along the NW Caldera, the Upper and Lower Cone sites, and the newly sampled Upper Caldera site. The NW Caldera wall and Upper Caldera vent fluid compositions are controlled by high-temperature water-rock interactions and phase separation between 2004 and 2018. Fe/Mn molar values suggest that the magmatic impact on all fields has been increasing over time. The Upper Cone has varying influences, including short term pulses of magmatic degassing, as revealed in K-Mg-SO4 ternary diagrams, Fe/Mn values, and δD and δ18O data. The Lower Cone is dominated by low temperatures and CO2 degassing and shows a pulse in magmatic influence in 2017, followed by a decrease toward earlier conditions in 2018. The 2017 pulse was accompanied by the increase of an enigmatic, soluble MgSO4 phase, potentially due to the “mining” of a magmatic brine sequestered inside the cone. Stable isotope data across the sites indicate pulses of magmatic waters in 2004 and 2017, immediately followed by episodes of more seawater-dominated fluids in 2005 and 2018. Magmatic degassing, phase separation, permeability, and mineral solubility all strongly influence changes in vent fluid composition. This study highlights the dynamic nature of the Brothers volcano hydrothermal system and the changes in fluid chemistry that may affect resultant mineralization.

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Brathwaite, Robert L., and Andrew J. Rae. "Epithermal Zeolite Alteration Associated with Siliceous Sinters, Hydrothermal Eruption Breccias, and Gold-Silver Mineralization, Central Taupo Volcanic Zone, New Zealand." Economic Geology, March 14, 2021. http://dx.doi.org/10.5382/econgeo.4820.

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Abstract In the central Taupo Volcanic Zone, extensive zeolite (mordenite ± clinoptilolite) alteration occurs in late Quaternary rhyolitic vitric tuffs that were deposited in a lake formed by caldera collapse following the ~290 Ka Ohakuri ignimbrite eruptions. Glass shards in lacustrine vitric tuffs of the Ngakuru Formation and in the underlying Ohakuri Formation ignimbrite are replaced by mordenite ± clinoptilolite, along with hydrothermal adularia, opal-A, opal-CT, and cristobalite. This mineral assemblage is also found in the outer alteration zones of the nearby Ohakuri and Tahunaatara epithermal gold prospects. Evaluation of whole-rock chemical analyses indicates that the zeolitized vitric tuffs show a slight gain in K, and Na, Ca loss relative to unaltered Ohakuri Formation pumice, which is reflected in the presence of hydrothermal adularia in the alteration assemblage. The mordenite ± clinoptilolite alteration is associated with siliceous sinters and hydrothermal eruption breccias that were formed in recently active (39–1.5 Ka) geothermal systems. By analogy with geothermal systems elsewhere in the Taupo Volcanic Zone at Wairakei and Ohaaki, the mordenite ± clinoptilolite alteration was formed from dilute alkali-chloride aqueous liquid at 60° to 150°C. Based on the close association of the mordenite ± clinoptilolite alteration with siliceous sinters and hydrothermal eruption breccias in the central Taupo Volcanic Zone, it is classified as shallow, low-temperature, epithermal alteration. Mordenite ± clinoptilolite alteration has also been identified in Quaternary rhyolitic caldera settings in Japan and the United States, where it is termed “caldera-type zeolitization.” In exploration for epithermal Au-Ag deposits in rifted arc settings, such alteration may be overlooked, given its subtle appearance and distal location relative to veins that mark upflow areas.

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Rubin, Allison, Kari M. Cooper, Marissa Leever, Josh Wimpenny, Chad Deering, Tyrone Rooney, Darren Gravley, and Qing-zhu Yin. "Changes in magma storage conditions following caldera collapse at Okataina Volcanic Center, New Zealand." Contributions to Mineralogy and Petrology 171, no. 1 (December 15, 2015). http://dx.doi.org/10.1007/s00410-015-1216-6.

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