Article
Geosciences, Multidisciplinary
S. C. Pearson-Grant, E. A. Bertrand
Summary: Topography plays a significant role in localizing convective upflows in geothermal systems, improving the accuracy of models and the agreement between upflow locations and low-resistivity zones derived from 3-D inversion of magnetotelluric data.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geology
Ian J. Hamling
Summary: This paper documents new InSAR observation of deformation over the cone volcanoes within the TVZ including the Tongariro Volcanic complex (TVC) and White Island. Observations over White Island support earlier observations indicating the stability of the crater wall is controlled, at least in part, by the water level in the crater lake. Deformation over the TVC is dominated by continued subsidence above the 2012 Te Maari eruption site with no evidence of deformation elsewhere.
NEW ZEALAND JOURNAL OF GEOLOGY AND GEOPHYSICS
(2021)
Article
Geochemistry & Geophysics
Colin J. N. Wilson, Simon J. Barker, Bruce L. A. Charlier, Madison L. Myers, Kristian F. Hansen
Summary: In this study, the validity, accuracy, and precision of rhyolite-MELTS modelling in inferring pre-eruptive magma storage conditions for eruptions at Taupo volcano, New Zealand are evaluated. Four major issues with the modelling are identified, including inappropriate application, mineralogical differences, temperature conflicts, and pressure errors, leading to the conclusion that the model is too imprecise for confident application in determining magma storage depths in the Taupo Volcanic Zone.
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
(2021)
Article
Geochemistry & Geophysics
Finnigan Illsley-Kemp, Simon J. Barker, Colin J. N. Wilson, Calum J. Chamberlain, Sigrun Hreinsdottir, Susan Ellis, Ian J. Hamling, Martha K. Savage, Eleanor R. H. Mestel, Fabian B. Wadsworth
Summary: Taupo volcano in New Zealand is an active and potentially hazardous volcano that underwent a period of unrest in 2019 characterized by increased seismic activity and ground deformation within the caldera. The analysis shows the presence of an aseismic zone coinciding with an inflating source, indicating the location of a magma reservoir with a significant volume and melt fraction. This highlights the importance of monitoring and understanding the behavior of this volcanic system.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geochemistry & Geophysics
Dale H. Burns, Shanaka L. de Silva, Phil Shane, Matthew A. Coble
Summary: Our understanding of magmatism in the New Zealand North Island subduction system is limited by our knowledge of the deep arc crust, particularly in the northern Taupo Volcanic Zone (NTVZ). This study uses detailed analysis of crystalline phases and melt inclusions to investigate the magmatic processes occurring in the lower crust beneath Putauaki in the NTVZ. The findings suggest a multi-stage evolution in the lower crust, with deep assimilation of isotopically enriched lower crust and subsequent ascension of evolved melts into the lower crust.
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
(2022)
Article
Geochemistry & Geophysics
Dongdong Yao, Zhigang Peng, Yoshihiro Kaneko, Bill Fry, Xiaofeng Meng
Summary: Large earthquakes can trigger various types of seismic responses in different regions, leading to dynamic stress perturbations and changes in seismicity rates. Understanding these triggering patterns and susceptibilities is crucial for time-dependent earthquake forecasting.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
R. F. D. McGregor, F. Illsley-Kemp, J. Townend
Summary: The Taupo Volcanic Zone is part of the Tonga-Kermadec volcanic arc in New Zealand and is characterized by extensional tectonic processes and magmatic activities. The seismicity in the Taupo Fault Belt, which is adjacent to the Taupo volcano, is influenced by regional tectonic and deep mafic magmatic systems. An increase in seismic activity in 2001 outside the caldera suggests that a magmatic intrusion beneath Lake Taupo's Western Bay initiated the unrest in the fault belt.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Geochemistry & Geophysics
Bogdan Matviichuk, Matt A. King, Christopher S. Watson, Machiel S. Bos
Summary: The study uses GPS observations of ocean tide loading displacements to infer the anelastic properties of the asthenosphere, finding strong spatial coherence of M-2 residuals across the North Island of New Zealand. The best fit model combines tide model, spatially variable ocean density and water compressibility, and Earth model, suggesting the need to consider the region's rheological structure to explain the observations.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geosciences, Multidisciplinary
James D. Muirhead, Finnigan Illsley-Kemp, Simon J. Barker, Pilar Villamor, Colin J. N. Wilson, Peter Otway, Eleanor R. H. Mestel, Graham S. Leonard, Susan Ellis, Martha K. Savage, Stephen Bannister, Julie V. Rowland, Dougal Townsend, Ian J. Hamling, Sigrun Hreinsdottir, Bubs Smith, Ross McGregor, Madisen Snowden, Yaasameen Shalla
Summary: The study focuses on the magmatic-tectonic processes associated with volcanic unrest at silicic calderas. Short-term deformation patterns, such as uplift, subsidence, seismic activity, and ground shaking, are observed, while long-term behavior shows suppression of axial subsidence of the rift basin due to magma influx. Silicic volcanic eruptions are characterized by intense syn-eruptive deformation, extending beyond the caldera structure.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geochemistry & Geophysics
Robert L. Brathwaite, Anthony B. Christie, Michael F. Gazley
Summary: The sand sequence at the north head of the Waikato River consists of Awhitu Sands, Hood Sands, and Mitiwai Sands, with rich titanomagnetite deposits. The titanomagnetite in the sands is mainly derived from andesitic rocks of the Taranaki Volcanoes 220km to the south, indicating a multistage formation process.
MINERALIUM DEPOSITA
(2021)
Article
Geology
Peter M. Otway, Finnigan Illsley-Kemp, Eleanor R. H. Mestel
Summary: This paper presents the monitoring of vertical deformation in the Lake Taupo area and provides a 42-year dataset. The study found that subsidence is occurring in the lakebed, while uplift episodes are observed in the northeastern sector, indicating both tectonic and volcanic deformation in the region.
NEW ZEALAND JOURNAL OF GEOLOGY AND GEOPHYSICS
(2022)
Article
Geochemistry & Geophysics
Ayla S. Pamukcu, Guilherme A. R. Gualda, Darren M. Gravley
Summary: The study compared the large-to-super-sized Oruanui and Taupo eruptions, finding new data supporting previous suggestions about system characteristics and adding additional details to the original conclusions.
CONTRIBUTIONS TO MINERALOGY AND PETROLOGY
(2021)
Article
Geochemistry & Geophysics
J. E. Delano, A. Howell, T. A. Stahl, K. Clark
Summary: This study utilizes historical aerial photos to build pre- and post-earthquake digital surface models (DSMs) and measures surface deformation parameters to investigate the geometry and slip distribution of fault rupture. The technique shows high accuracy and resolution, and can better distinguish between new and pre-existing fault scarps.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
Kevin F. Lally, Jacqueline Caplan-Auerbach, John A. Power
Summary: Tanaga Island has four stratovolcanoes, with only Tanaga having a confirmed record of historical eruptive activity. The study uses seismic relocations to gain insight into volcanic and tectonic activity in the region. The results show that volcanic activity is relatively rare compared to tectonic activity.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2023)
Article
Geochemistry & Geophysics
Yasuhiro Hirai, Yoshihiko Tamura, Tomoki Sato, Takashi Miyazaki, Qing Chang, Bogdan S. Vaglarov, Jun-Ichi Kimura, Kaj Hoernle, Reinhard Werner, Folkmar Hauff, Christian Timm
Summary: This study presents the petrology of volcanic rocks dredged from the Kermadec arc, providing evidence for the occurrence of primary andesitic magmas in the arc. The thin crust of the Kermadec arc allows for low-pressure conditions in the uppermost mantle, enabling the generation of primary andesitic melts. This supports the hypothesis that primary andesitic magmas generate in arc where the crust is thin.
JOURNAL OF PETROLOGY
(2023)
Letter
Multidisciplinary Sciences
Robyn Pickering, Andy I. R. Herries, Jon D. Woodhead, John C. Hellstrom, Helen E. Green, Bence Paul, Terrence Ritzman, David S. Strait, Benjamin J. Schoville, John Hancox
Article
Geology
Tod Waight, Kirstine Malloch, Steve Weaver, Trevor Ireland, Roddy Muir
Summary: The Foulwind and Windy Point Granites are important components of high-field strength element-enriched Carboniferous granitoids in New Zealand's Western Province. With four identified phases, the rocks are enriched in high-field strength elements, with the Tauranga Bay and Lighthouse phases classified as ferroan A-type granites. Nd isotope compositions indicate involvement of multiple sources, and the A-type signatures can be explained by melting of mid-Paleozoic I-type granites with Greenland Group metasediments. The tectonic setting of the Foulwind Suite remains uncertain, potentially related to post-amalgamation processes following the generation of voluminous mid-Paleozoic granitoids in the region.
NEW ZEALAND JOURNAL OF GEOLOGY AND GEOPHYSICS
(2022)
Article
Multidisciplinary Sciences
Nao Nakanishi, Andrea Giuliani, Richard W. Carlson, Mary F. Horan, Jon Woodhead, D. Graham Pearson, Richard J. Walker
Summary: Globally distributed kimberlites show broadly chondritic initial Nd-143-Hf-176 isotopic systematics, suggesting they may originate from a chemically homogenous, relatively primitive mantle source. The study indicates that these kimberlites were possibly derived from long-lived early formed mantle reservoirs. The negative mu W-182 values in some kimberlites could be attributed to various factors such as W transfer, early silicate fractionation, or late-accreted materials.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Geochemistry & Geophysics
Robert W. Nicklas, Alan D. Brandon, Tod E. Waight, Igor S. Puchtel, James M. D. Day
Summary: Ocean island basalts exhibit significant variations in isotopic compositions, indicating contributions from multiple mantle sources including ancient refractory sources and recycled oceanic crustal components. Different isotopic systems show correlations, such as between Os and Pb, implying binary mixing between depleted and enriched sources. The presence of highly depleted mantle sources and recycled oceanic crust components are identified, with implications for the origin and evolution of the Icelandic plume.
Article
Geosciences, Multidisciplinary
Adam A. Garde, Nynke Keulen, Tod Waight
Summary: Sand-sized impactite melt grains, handpicked from a glaciofluvial sample near the Hiawatha impact crater in Northwest Greenland, provide new information about the crystallization and cooling history of this impact structure concealed by the Greenland Ice Sheet.
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
(2022)
Review
Geosciences, Multidisciplinary
Ake Johansson, Bernard Bingen, Hannu Huhma, Tod Waight, Rikke Vestergaard, Alvar Soesoo, Grazina Skridlaite, Ewa Krzeminska, Leonid Shumlyanskyy, Mark E. Holland, Christopher Holm-Denoma, Wilson Teixeira, Frederico M. Faleiros, Bruno Ribeiro, Joachim Jacobs, Chengcheng Wang, Robert J. Thomas, Paul H. Macey, Christopher L. Kirkland, Michael I. H. Hartnady, Bruce M. Eglington, Stephen J. Puetz, Kent C. Condie
Summary: This research compiles a large amount of magmatic U-Pb ages data from different blocks, revealing the temporal relationships and geological events among various blocks during the formation of Columbia and Rodinia. There is a certain degree of correlation between various blocks, but there are also significant differences.
PRECAMBRIAN RESEARCH
(2022)
Article
Geosciences, Multidisciplinary
Tod Waight, Mikael Stokholm, Benjamin Heredia, Tonny B. Thomsen
Summary: A granitic sample from Christianso island in Denmark was studied petrographically and geochemically. The U-Pb dating of zircon and titanite revealed an age of around 1500 Ma. The sample contains a significant number of inherited and disturbed zircons, indicating geological complexity and possible Pb loss. The petrographical and geochemical characteristics of Christianso granite are similar to those of A-type granites and gneisses found in Bornholm and southern Sweden.
BULLETIN OF THE GEOLOGICAL SOCIETY OF DENMARK
(2022)
Article
Multidisciplinary Sciences
Andrea Giuliani, Russell N. Drysdale, Jon D. Woodhead, Noah J. Planavsky, David Phillips, Janet Hergt, William L. Griffin, Senan Oesch, Hayden Dalton, Gareth R. Davies
Summary: The carbon cycle of Earth is influenced by the subduction of sedimentary material into the mantle. Changes in the composition of sedimentary subduction flux over Earth's history have had an unclear impact on the mantle carbon cycle. This study shows that the carbon isotopes of kimberlite magmas reflect a fundamental change in their deep-mantle source compositions during the Phanerozoic Eon. The findings suggest that biogeochemical processes on Earth's surface have a significant influence on the deep mantle, establishing a connection between the deep and shallow carbon cycles.
Article
Geochemistry & Geophysics
Hayden Dalton, Andrea Giuliani, Janet Hergt, David Phillips, Hugh O'Brien, Maxim D. Ballmer, Roland Maas, Jon Woodhead
Summary: The origin of kimberlites and related magmas is still unclear. This study investigates the isotopic signatures of different occurrences of kimberlites, lamproites, and ultramafic lamprophyres in Finland. The results suggest that these magmas have different sources and were emplaced in response to various tectonic events. The findings provide important insights into the origin and geological evolution of kimberlites.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Geochemistry & Geophysics
L. H. Pilbeam, T. M. Rasmussen, T. E. Waight, T. F. D. Nielsen
Summary: A model is developed to test the hypothesis of kimberlite formation. The model uses inversion calculations to calculate the mass fraction of xenocrystic minerals and the source mineralogy and melt degree in the source region. The calculation is applied to a data set from the Majuagaa kimberlite dyke, and the results support the simple model of kimberlite formation involving low-degree melting, melt extraction and concentration, and entrainment and reaction with lithospheric mantle material.
JOURNAL OF PETROLOGY
(2023)
Article
Geochemistry & Geophysics
William R. Hyde, Adam A. Garde, Nynke Keulen, Sebastian N. Malkki, Steven J. Jaret, Tod Waight, Pierre Beck, Iain McDonald, Nicolaj K. Larsen
Summary: Impact melt rocks collected near the Hiawatha impact structure in northwest Greenland provide valuable evidence for studying impact structures. The melt rocks exhibit various shock indicators and can be classified into three groups based on their textures and chemistry. The presence of well-preserved organic material suggests a dense high-latitude temperate forest in North Greenland at the time of impact. These findings demonstrate the potential to study hidden impact structures beneath an ice sheet by analyzing transported samples, which could lead to the discovery of other potential impact craters in Greenland and Antarctica.
METEORITICS & PLANETARY SCIENCE
(2023)
Review
Geosciences, Multidisciplinary
R. E. Turnbull, J. J. Schwartz, M. L. Fiorentini, K. A. Klepeis, R. Jongens, E. Miranda, N. J. Evan, T. Ludwig, T. Waight, K. Faure, B. J. McDonald
Summary: In this study, the crustal architecture of the Zealandia Cordillera along the former Gondwana supercontinent is examined using isotopic contour maps and mixing models. The results show that the lithospheric architecture influenced magmatism and deformation, while lower-plate processes also played a significant role. The isotopic comparisons across separated continental landmasses support previous correlations.
Article
Geosciences, Multidisciplinary
Andreas Petersson, Ulf Soderlund, Anders Schersten, Tod Waight, Mimmi K. M. Nilsson, Jeff Vervoort
Summary: While it is now common to use Hf isotope analysis of accessory zircon in intermediate to silicic rocks, analysis of whole-rock Lu-Hf isotope remains necessary for obtaining the initial Hf isotope signatures of old mafic rocks. However, whole-rock analysis is particularly important for Si-poor rocks with a metamorphic imprint due to the sensitivity of baddeleyite, commonly used for U-Pb age analyses of mafic rocks, to alteration and metamorphism. This study demonstrates the feasibility of using whole-rock analysis for determining initial Nd and Hf values in (meta-)mafic rocks despite deformation and metamorphism under hydrated amphibolite-grade conditions.
PRECAMBRIAN RESEARCH
(2023)
Article
Geochemistry & Geophysics
Nick Mortimer, Simon Williams, Maria Seton, Andy Calvert, Tod Waight, Rose Turnbull, Demian Nelson, Mike Palin, Jahandar Ramezani, Matthew W. Sagar, Andy Tulloch, Wanda Stratford, Julien Collot, Samuel Etienne
Summary: New rock dredge samples from the seabed of northern Zealandia provide key information for establishing the geological framework of this submerged continent. Analytical work on these samples, including petrography, geochemical analyses, and geochronology, reveals the depositional ages and composition of the rocks. This study, along with previous research and magnetic anomaly data, allows for the mapping of major geological units in North Zealandia.
Article
Environmental Sciences
Rieneke Weij, Jon D. Woodhead, J. M. Kale Sniderman, John C. Hellstrom, Elizabeth Reed, Steven Bourne, Russell N. Drysdale, Timothy J. Pollard
Summary: This study investigates the Naracoorte Cave Complex in Australia using dating techniques and analyses of charcoal and pollen. The results show that the caves began forming 1.34 million years ago and opened to the atmosphere 600,000 years ago, providing an upper limit on the accumulation of fossils.
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)