S. J. Barker

S. J. Barker
Victoria University of Wellington ·  School of Geography, Environment and Earth Sciences

BSc (Hons), MSc, PhD

About

49
Publications
25,153
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Introduction
My research specialties include volcanology, geochemistry, petrology, and the development of novel techniques to study magmatic systems and the timing and impacts of large explosive volcanic eruptions on the environment, climate, and humans. My research entails two main streams of investigation: field studies of volcanic deposits and geochemical analysis of rocks and minerals. The combination of these two approaches provides insights into the processes that go on prior to eruptions.
Additional affiliations
January 2015 - present
University of Auckland
Position
  • PostDoc Position
January 2015 - January 2015
Victoria University of Wellington
Position
  • PostDoc Position

Publications

Publications (49)
Article
Full-text available
A major challenge in volcanology is determining the factors that control the frequency and magnitude of eruptions at hazardous caldera volcanoes. Understanding the critical sequence of events that may lead to future eruptions is vital for volcanic monitoring and risk assessment. Here we use magma chemistry and mineral diffusion modeling to interpre...
Article
Full-text available
Supereruptions (>1015 kg ≈ 450 km3 of ejected magma) have received much attention because of the challenges in explaining how and over what time intervals such large volumes of magma are accumulated, stored, and erupted. However, the processes that follow supereruptions, particularly those focussed around magmatic recovery, are less fully documente...
Article
Full-text available
New zircon U-Th model age and trace element data sets are presented from Taupo volcano (New Zealand), to investigate the timescales and broad-scale magmatic processes involving zircon crystallisation after the caldera-forming 25.4 ka Oruanui supereruption. Detailed 14C-based chronologies and controls on vent locations allow the timing and location...
Article
Full-text available
Many submarine caldera volcanoes are blanketed with deposits of highly vesicular pumice, typically attributed to vigorous explosive activity. However, it is challenging to relate volcanic products to specific eruptive styles in submarine volcanism. Here we document vesicularity and textural characteristics of pumice clasts dredged from the submarin...
Article
Full-text available
The geochemistry of pyroclasts sampled from four volcanoes along the Kermadec arc in the SW Pacific is used to investigate the genesis of silicic magmas in a young (< 2 Myr), archetypical intra-oceanic arc setting. Raoul, Macauley and Raoul SW volcanoes in the northern Kermadec arc, and Healy volcano in the southern Kermadec arc have all recently e...
Article
Full-text available
Chemical anomalies in polar ice core records are frequently linked to volcanism; however, without the presence of (crypto)tephra particles, links to specific eruptions remain speculative. Correlating tephras yields estimates of eruption timing and potential source volcano, offers refinement of ice core chronologies, and provides insights into volca...
Article
Full-text available
Volatile measurements in mineral-hosted sealed melt inclusions, and open-ended embayments, have previously been used to study magma ascent dynamics in large rhyolitic eruptions. However, despite occurring more frequently, smaller-volume explosive events remain under-studied. We present magmatic volatile data from quartz-hosted melt inclusions and e...
Article
Full-text available
The ~25.5‐ka Ōruanui supereruption (Taupō volcano, New Zealand) erupted >1100 km3 of pyroclastic material during the Last Glacial Maximum. The impacts of this event on climate and the New Zealand environment remain unresolved, particularly on ecological timescales. Using sediment cores from Onepoto maar palaeolake, Auckland (~240 km upwind from sou...
Article
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Oxygen isotopes are useful for tracing interactions between magmas, crustal rocks and surface‐derived waters. We use them here to consider links between voluminous silicic magmatism and large‐scale hydrothermal circulation in New Zealand's central Taupō Volcanic Zone (TVZ). We present >350 measurements of plagioclase, quartz, hornblende and groundm...
Article
Full-text available
The transport and degassing pathways of volatiles through large silicic magmatic systems are central to understanding geothermal fluid compositions, ore deposit genesis, and volcanic eruption dynamics and impacts. Here, we document sulfur (S), chlorine (Cl), and fluorine (F) concentrations in a range of host materials in eruptive deposits from Taup...
Article
Full-text available
Lake Taupō (Taupō-nui-a-Tia) infills the composite caldera above an active rhyolitic magmatic system in the central Taupō Volcanic Zone (TVZ). Ground deformation is a key unrest indicator at Taupō volcano. We present a spreadsheet tool, TaupōInflate, to calculate and plot ground deformation from magmatic inflation at depth beneath Taupō caldera. Ex...
Article
Full-text available
We present a petrologic study of the ca. 110 ka Halarauður eruption (7 ± 6 km³ magma), associated with collapse of Krafla caldera in northeast Iceland. Whole-rock compositions of juvenile Halarauður products span a continuous range between quartz tholeiite basalt (50.0 wt% SiO2, 5.0 wt% MgO; Mg# 42) and rhyolite (74.6 wt% SiO2). Linear correlations...
Article
Full-text available
Intra-oceanic arcs are typically associated with intermediate (andesitic) cone volcanoes. However, caldera volcanoes may also form in these settings from very large eruptions, resulting in sudden changes to the magma reservoir. These reservoirs can then produce either semi-continuous or intermittent low-intensity volcanism between major caldera-pro...
Preprint
Intra-oceanic arcs are typically associated with intermediate (andesitic) cone volcanoes. However, caldera volcanoes may also form in these settings from very large eruptions, resulting in sudden changes to the magma reservoir. These reservoirs can then produce eithersemi-continuous or intermittent low-intensity volcanism between major caldera-prod...
Article
We consider here the validity, accuracy, and precision of rhyolite-MELTS modelling in inferring the pre-eruptive magma storage conditions for the caldera-forming 25.5 ka Oruanui and 232 CE (1.72 ka) Taupō eruptions at Taupō volcano, New Zealand as proposed by Pamukçu et al. (2020: Contrib Mineral Petrol 175: 48). There are four major issues with th...
Article
Full-text available
We present a full characterization of a 20 cm‐thick tephra layer found intercalated in the marine sediments recovered at Site U1524 during International Ocean Discovery Program (IODP) Expedition 374, in the Ross Sea, Antarctica. Tephra bedforms, mineral paragenesis, and major‐ and trace‐element composition on individual glass shards were investigat...
Article
Full-text available
We present a detailed petrologic study of rhyolites from seven eruptions spanning the full (∼190 k.y.) history of rhyolitic volcanism at Krafla volcano, northeast Iceland. The eruptions vary widely in size and style, but all rhyolites are crystal-poor (<6 modal%: plagioclase + augite ± pigeonite ± orthopyroxene ± titanomagnetite ± fayalite) and hav...
Article
Supereruptions are the largest explosive volcanic eruptions on Earth. They generate catastrophic, widespread ash-fall blankets and voluminous ignimbrites, with accompanying caldera collapse. However, the mechanisms of generation, storage and evacuation of the parental silicic magma bodies remain controversial. In this Review, we synthesize field, l...
Article
Full-text available
Plain Language Summary Taupō in New Zealand, is a large caldera volcano which has been very active in recent geological time, but has not erupted for about 1,800 years. However, in historical times it has undergone periods of unrest involving abundant, sometimes damaging earthquakes, and ground deformation, but no eruption. In 2019, Taupō volcano u...
Article
The magmatic systems that feed supereruptions result from high magma supply from depth that sustains large regions of partial melt in the shallow crust. However, many questions remain around the processes and timescales over which super-sized magmatic systems develop. We present new zircon age, trace elemental and isotopic data from the Jemez Mount...
Article
Full-text available
Tarawera volcano (New Zealand) is volumetrically dominated by rhyolitic lavas and pyroclastic deposits, but the most recent event in AD 1886 was a basaltic Plinian fissure eruption. In March 2019 a swarm of at least 64 earthquakes occurred to the NE of Tarawera volcano, as recorded by the New Zealand Geohazard Monitoring Network (GeoNet). We use se...
Article
Full-text available
Taupō volcano (New Zealand) is distinguished as the source of Earth's youngest supereruption (∼25.5 ka), with Lake Taupō occupying the resulting caldera. Taupō has also produced eruptions of a wide variety of sizes, styles and associated landscape responses over a ∼350 kyr period. Early Taupō (>54 ka) is poorly demarcated, merging with Maroa to the...
Article
Full-text available
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 a...
Article
Full-text available
Deposits of the ca. 110 ka Halarauður eruption of Krafla caldera (reconstructed volume = 7 ± 6 km3 dense rock equivalent) include the only spatter-rich ignimbrite known in Iceland, and an exceptionally rare lava-like basaltic ignimbrite. We present a revised stratigraphy and new whole-rock major-element data set for products of this unusual event,...
Poster
Abrupt volcanogenic cooling of the Earth - “volcanic winters” - has been documented after historic eruptions, but the impacts of the largest known events remains highly speculative. Scientific drilling of sediment and ice cores has recovered Antarctic palaeoclimate records that provide a unique opportunity to determine how and at what rate the clim...
Article
Full-text available
Hazard analysis at caldera volcanoes is challenging due to the wide range of eruptive and environmental conditions that can plausibly occur during renewed activity. Taupo volcano, New Zealand, is a frequently active and productive rhyolitic caldera volcano that has hosted the world's youngest known supereruption and numerous smaller explosive event...
Conference Paper
Full-text available
The Jemez Mountains volcanic field (JMVF) hosts two cataclysmic caldera-forming eruptions at 1.60 and 1.25 Ma that produced the rhyolitic Otowi Member (383 cubic kilometers) and Tshirege Member (∼400 cubic kilometers) of the Bandelier Tuff, respectively. These eruptive events postdate a long history (∼10 m.y.) of volcanism dominated by intermediate...
Conference Paper
The Taupō volcanic zone (TVZ), New Zealand, is a global end-member of continental volcanic arcs. The central TVZ features exceptionally high heat-flow and hosts one of the most productive and frequently active silicic mag-matic systems on Earth, which is ultimately driven by large volumes of mafic magma from the mantle. We here consider the possibl...
Article
Full-text available
Quenched juvenile mafic inclusions (enclaves) are an occasional but informative component in the deposits of large felsic eruptions. Typically, the groundmasses of these inclusions rapidly crystallize as the mafic magma is chilled against a more voluminous, cooler felsic host, providing a physical and chemical record of the nature and timing of maf...
Article
Rubin et al. (Reports, 16 June 2017, p. 1154) proposed that gradients in lithium abundance in zircons from a rhyolitic eruption in New Zealand reflected short-lived residence at magmatic temperatures interleaved with long-term “cold” (<650°C) storage. Important issues arise with the interpretation of these lithium gradients and consequent crystal t...
Article
Submarine volcanic eruptions are frequent and important events, yet they are rarely observed. Here we relate bathymetric and hydroacoustic images from the 2011-2012 El Hierro eruption with surface observations and deposits imaged and sampled by ROV. As result of the shallow submarine eruption, a new volcano named Tagoro grew from 375 to 89 m depth....
Article
Full-text available
A recent volcanic eruption near Tonga in the southwest Pacific created a new island, giving scientists a rare opportunity to explore the volcanic record of this remote region.
Article
Full-text available
We use comprehensive geochemical and petrological records from whole-rock samples, crystals, matrix glasses and melt inclusions to derive an integrated picture of the generation, accumulation and evacuation of 530 km³ of crystal-poor rhyolite in the 25.4 ka Oruanui supereruption (New Zealand). New data from plagioclase, orthopyroxene, amphibole, qu...
Article
Despite increasing recognition of silicic pumice-bearing deposits in the deep marine environment, the processes involved in explosive silicic submarine eruptions remain in question. Here we present data on bubble sizes and number densities (number of bubbles per unit of melt matrix) for deep submarine erupted pumices from three volcanoes (Healy, Ra...
Article
Full-text available
Critical to understanding explosive eruptions is establishing how accurately representative pyroclasts are of processes during magma vesiculation and fragmentation. Here, we present data on densities, and vesicle size and number characteristics, for representative pyroclasts from six silicic eruptions of contrasting size and style from Raoul volcan...
Article
Full-text available
Pyroclastic deposits from four caldera volcanoes in the Kermadec arc have been sampled from subaerial sections (Raoul and Macauley) and by dredging from the submerged volcano flanks (Macauley, Healy, and the newly discovered Raoul SW). Suites of 16–32 mm sized clasts have been analyzed for density and shape, and larger clasts have been analyzed for...
Article
Pumice textures from subaerial explosive eruptions have been relatively well documented yet little is known about their submarine equivalents. The Kermadec Arc presents a unique opportunity to investigate the processes of submarine explosive volcanism, as it contains silicic volcanoes of similar age that have erupted chemically similar magmas at di...
Article
Recent work has shown that silicic volcanism can be abundant in intra-oceanic subduction settings, and is often associated with large explosive caldera forming eruptions. Several major petrogenic questions arise from the generation and eruption of large silicic magma bodies in such a simple subduction setting, where continental crust is absent. We...
Article
Explosive volcanism involving crystal-poor dacite to rhyolite magmas is common in the young records of many volcanoes along the intraoceanic Kermadec arc. Such volcanism occurs at both submarine and subaerial volcanoes, and is often of a size that caldera collapse occurs. Three volcanoes present unique circumstances that can provide insights into t...
Article
Raoul Island is the emergent 30 square km portion of a > 200 cubic km volcanic edifice which rises 900 m from the sea floor along the Kermadec ridge. Although the island is composed mainly of basalt and basaltic andesite, the last 4000 years has seen several dacitic explosive eruptions associated with caldera formation [Lloyd & Nathan, N.Z. Geol. S...
Article
Recent work has shown that silicic volcanism can be abundant in intra-oceanic subduction settings, and is often associated with large explosive caldera-forming eruptions. Several major petrogenetic questions arise over the origin and eruption of large amounts of silicic magma at these relatively simple subduction settings. This study has investigat...

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