ANU Research Publications
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The Australian National University's Research Publications collection is an online location for collecting, preserving and disseminating the scholarly output of the University. This service allows members of the University to share their research with the wider community. ANU Open Research accepts journal articles, conference papers, book chapters, working or technical papers and other forms of scholarly communication.
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Item Open Access Chromium stable isotope distributions in the southwest Pacific Ocean and constraints on hydrothermal input from the Kermadec Arc(Elsevier Ltd., 2023) Janssen, David J.; Gilliard, Delphine; Rickli, Jorg; Nasemann, Philipp; Koschinsky, Andrea; Hassler, Christel S; Bowie, Andrew; Ellwood, Michael; Kleint, Charlotte; Jaccard, SamuelSpecial attention has been given to chromium (Cr) as a paleoproxy tracing redox cycling throughout Earth’s history, due to differences in the solubility of its primary redox species at Earth’s surface (Cr(III) and Cr(VI)) and isotope fractionation associated with their interconversion. In turn, chromium’s paleoproxy potential has motivated studies of the modern ocean to better understand which processes drive its cycling and to constrain their impact on the Cr isotope composition (δ53Cr) of seawater. Here, we present total dissolved seawater Cr concentrations and δ53Cr along the GEOTRACES GP13 section. This section is a zonal transect extending from Australia in the subtropical southwest Pacific Ocean. Surface signals of local biological Cr cycling are minimal, in agreement with distributions of dissolved major nutrients as well as biologically-controlled trace metals in this low productivity, oligotrophic environment. Depth profiles have Cr concentration minima in surface waters and maxima at depth, and are largely shaped by the advection of nutrient- and Cr-rich subsurface waters rather than vertically-driven processes. Samples close to the sediment–water interface indicate important benthic Cr fluxes across the section. The GP13 transect crosses the hydrothermally-active Kermadec Arc. Hydrothermal fluids (consisting of <15% background seawater) were collected from three venting sites at the Brothers Volcano (along the Kermadec Arc). These fluids yielded near-crustal δ53Cr values (−0.17 to +0.08‰) and elevated [Cr] (7.5–23 nmol kg−1, hydrothermal endmember [Cr] ≈ 8–27 nmol kg−1), indicating that the Kermadec Arc may be an isotopically light Cr source. Dissolved [Fe] enrichments have been reported previously in deep waters (∼1600–3000 m) along the GP13 transect, east of the Kermadec Arc. These same waters show elevated [Cr] compared to Circumpolar Deep Water ([Cr] = 3.88 ± 0.11, δ53Cr = 0.89 ± 0.08, n = 32), with an average [Cr] accumulation of 0.71 ± 0.11 nmol kg−1 (1 SD), and an estimated δ53Cr of +0.46 ± 0.30‰ (2 SD, n = 9) for the accumulated Cr. Comparing high-temperature vent and neutrally buoyant plume data, hydrothermal-sourced Cr is likely negligable compared to Cr contributions from other processes (benthic fluxes, release from particles), and the advection of more Cr-rich Pacific Deep Water. It is unlikely that hydrothermal vents would be a major contributor within the regional or global biogeochemical Cr cycle, even if hydrothermal fluxes change by orders of magnitude, and therefore δ53Cr trends in the paleorecord may be attributable, at least in part, to major changes in other controls on Cr (e.g. widespread anoxia).Item Embargo Boron isotopes in blue diamond record seawater-derived fluids in the lower mantle(Elsevier, 2023) E. Regier, Margo; V. Smit, Karen; Chalk, Thomas B; Stachel, Thomas; Stern, Richard A; M. Smith, Evan; Foster, Gavin L; Bussweiler, Yannick; DeBuhr, Chris; Burnham, Antony; Harris, Jeffrey WBoron is a quintessential crustal element but its conspicuous presence in diamond – a mantle mineral – raises questions about potential subduction pathways for boron and other volatiles. It has been a long-standing goal to characterize the isotopic composition of boron in blue, boron-bearing (Type IIb) diamonds to reveal its origin. Mineral inclusions indicate that Type IIb diamonds crystallize at transition zone to lower mantle depths, meaning that if the boron is subducted it would trace a pathway of volatile elements into the deep mantle. Here, using off-line laser ablation sampling, we present the first boron isotope compositions, along with trace element contents and carbon isotope compositions, of a suite of blue diamonds mainly sourced from the Cullinan diamond mine in South Africa. The ten analyzed blue diamonds have a wide range in B, between −9.2 ± 2‰ and −0.5 ± 2‰, compared to the more restricted range for mid-ocean ridge basalts (−7.1 ± 0.9‰). Carbon isotope values for the blue diamonds range between −20.6 and −1.8‰, with a mode at −17‰, significantly more negative than the main mantle mode at −5‰. Combined, the boron and carbon isotope compositions require fluid input from subducted oceanic lithosphere down into deep mantle source regions of blue diamonds. This finding highlights a deep subduction pathway for volatiles to stoke the source regions of deeply-derived magmas.Item Open Access Characterization of Changes in Groundwater Storage in the Lachlan Catchment, Australia, Derived From Observations of Surface Deformation and Groundwater Level Data(Wiley Blackwell, 2022) Razeghi, Mahdiyeh; Tregoning, Paul; Shiezaei, Manoochehr; Ghobadi‑Far, Khosro; McClusky, Simon; Renzullo, LuigiGlobal Positioning System (GPS) deformation measurements were combined with groundwater level data to examine the spatiotemporal variability of groundwater storage in the Lachlan catchment located in central New South Wales (Australia). After correcting for effects of glacial isostatic adjustment, non-tidal oceanic and atmospheric loading as well as hydrologic loading using existing models, we show that the seasonal and interannual variability of ground deformation and hydraulic head level data, extracted using wavelet time-frequency analysis, exhibits an in-phase behavior, indicating that the observed surface deformation is the poroelastic response to groundwater pressure change in aquifer system. Combination of GPS displacement and groundwater level change enables the estimation of elastic skeletal specific storage coefficients, which were then used for estimating groundwater storage changes. The estimated groundwater storage changes clearly reflect the four climate events of the Lachlan catchment since 1996: (a) the Millennium drought over 1996–2009, (b) the 2011–2012 La Nina and two significant floods in 2012 and 2016, (c) the drought conditions from mid-2017 to late-2019, and (d) the return of La Nina conditions since early 2020. We also found annual and long-term groundwater storage variations of respectively urn:x-wiley:21699313:media:jgrb55985:jgrb55985-math-0001 and urn:x-wiley:21699313:media:jgrb55985:jgrb55985-math-0002 over the period 2012–2021. Moreover, we show that groundwater level fluctuations can be predicted from GPS displacement measurements and storage coefficients with sufficient accuracy (80% correlation and 70% RMS reduction when compared in terms of seasonal cycle). This study provides essential information that can contribute to future groundwater planning, management, and control over the Australian continent.Item Open Access Neoarchean to Rhyacian crustal records along the Middle Xingu River area, Amazonian craton(Sociedade Brasileira de Geologia, 2022) Buenano Macambira, Moacir José; Lacerda Vasquez, Marcelo; Conduru Monteiro, Pablo; Armstrong, RichardThe Carajás (3.0–2.5 Ga) and Xingu-Iricoumé (1.99–1.86 Ga) blocks comprise the Central Amazonia Province (CAP) that is in contact with the Maroni-Itacaiúnas Province (MIP) within the Amazonian craton. The CAP is the oldest portion (Nd-TDM) of the craton and corresponds to an Archean nucleus bordered by younger Paleo-Mesoproterozoic mobile belts, including the MIP. Because the location and tectonic boundaries between these provinces are insufficiently known, we carried out a geological survey along the Middle Xingu River, cutting the WNW-ESE regional trend, to further understand cratonic evolution of the MIP and its southeastern boundary in this key area. Geochronologic results (Pb-evaporation and U-Pb SHRIMP in zircon and monazite), supported by petrographic and field observations, allowed identification of the following lithotypes and their ages: migmatitic gneisses (2859–2080 Ma), tonalitic gneisses (2554 ± 3 Ma, 2480 ± 9 Ma), enderbites (2114 ± 3 Ma), charnockites (2094 ± 4 Ma, 2084 ± 2 Ma), granodiorites (2079 ± 3 Ma), leucogranitic vein (2075 ± 2 Ma), and pelitic paragneisses (2062 ± 8 Ma). These ages are related to the reworking of Archean crust during Rhyacian magmatic arc amalgamation (2.22–2.13 Ga) and collision in the Transamazonian cycle (ca. 2.1 Ga).Item Embargo The Politics of the Social Biographical Approach to Working-Class Leaders(Cambridge University Press, 2022) Nolan, MelanieIn this paper, I consider John French's biography, Lula and His Politics of Cunning: From Metalworker to President of Brazil (2020). French discusses his methodology, which he characterizes as "a social biographical approach". I argue that this methodology is already in historians' toolkit. Historians writing biography seem to start with first premises rather than building on what went before. I thus contextualize the methodology, situating French's biography of Lula within more general shifts in approaches to biography.Item Open Access Champions of change: The second-wave feminists who fought for equal pay(The Australian National University, 2021-08-30) Nolan, MelanieIt puts the spotlight on two feminists Patricia Ann Conlin (1939-1970) and Edna Ryan (1904-1997) and their second-wave feminism.Item Embargo Deep earthquake study still resonant at 100(Oxford University Press, 2022) Kennett, BrianA century on from the first dedicated geophysical publication by the RAS, Brian Kennett reflects on its first article, presenting evidence for deep earthquakes.Item Open Access Life sentences - Keeping biographies in the family(The Australian National University, 2022-08-06) Nolan, MelanieSome families seem to have a lot of writing talents and involvement in biographical practices. This piece explores one such family, Sir Leslie Stephen and his daughter, Virginia Woolf.Publication Open Access La Inevitable Resurreccion de los Cerebros de Boltzmann : una novela con ecuaciones [Second Edition](Ediciones Ayarmanot (Buenos Aires); Encuentro Incorporated (Canberra), 2024) Martín, Mario DanielPublication Open Access Iridio ennui vs the Boltzmann Brains: a novel with equations(Ayarmanot, 2024) Martín, Mario DanielIridio Ennui vs The Boltzmann Brains by Mario Daniel Martín is the translation of the second edition of La inevitable resurrección de los cerebros de Boltzmann (The electronic version of the novel is freely downloadable from: https://www.edicionesayarmanot.com/2024/07/cerebros-de-boltzmann-2da-edicion.html ) Ediciones Ayarmanot is now publishing both the second edition in Spanish and the English translation, in collaboration with Encuentro Incorporated of Canberra, Australia.Item Embargo Tinkering with the Temple of Fame or systematically reimagining the Australian Dictionary of Biography?(Professional Histories Association, Victoria, 2022) Nolan, MelanieAll readers of Circa will have used the Australian Dictionary of Biography (ADB), and some will have written entries. This paper sets out the technological and cultural changes which have led to the development and expansion of the ADB, which is now one part of a digital information suite. Where once revisions were envisaged of a 'tinkering' or corrigenda kind, now it is all too clear that the ADB needs revising systematically. The ADB's revision plans rely on its national collaboration, its volunteer and unpaid working party members and authors. This article reminds professional historians that the ADB will be only too pleased to hear from them if they come across candidates for inclusion in the dictionary. Indeed, it may well be able to commission proposers to write the entries.Item Metadata only L'Histoire cachée d’Australie(SBS, 2024) Fathi, RomainDans cette série de podcasts, nous allons vous faire découvrir l’Australie différèrent, à travers son histoire cachéeItem Metadata only Come Together [Live Performance](ANU School of Music, 2011-10-18) Nguyen, Le-TuyenDESCRIPTION: Original composition for guitar and percussion incorporating musical materials from the Vietnamese Gong culture which was recognized as World Intangible cultural heritage by UNESCO in 2005. RESEARCH CONTRIBUTION: 1)Incorporation of new combinations of sound sources: guitar, African djembe and Indian foot jingles. 2) The crossing-over and fusion of Western Art Music and world tradition music 3) The inclusion of new tuning for guitar RESEARCH SIGNIFICANCE: 1) Professor Salil Sachdev is Chair of Music Department at Bridgewater State University USA. 2) The Horace Auditorium is one of the main concert halls in Massachusetts USA.Item Metadata only Biography: An Historiography(Routledge, 2023) Nolan, MelanieBiography: An Historiography examines how Western historians have used biography from the nineteenth century to the present - considering the problems and challenges that historians have faced in their biographical practice systematically. This volume analyses the strategies and methods that historians have used in response to seven major issues identified over time to do with evidence, including but not limited to the problem of causation, the problem of fact and fiction, the problem of other minds, the problem of significance or representativeness, the problems of perspective, both macro and micro, and the problem of subjectivity and relative truth. This volume will be essential for both postgraduates and historians studying biography.Item Open Access A New Method for Relating Zircon Crystallisation to Petrogenetic Events(Oxford University Press, 2022) Miller, Laura; Cawood, Peter A.; Berry, AndrewThe trace element contents of zircon can provide unique insights into tectonothermal events, however, interpreting these data and identifying correlations with specific magmatic/metamorphic events can be challenging. This limits our ability to construct temporally constrained petrogenetic histories of complex metamorphic terranes. Unlocking the information that the rare earth element (REE) patterns of zircon contain is difficult because of the need to quantify differences. We have parametrised the shape of zircon REE patterns in terms of three independent parameters: average abundance, slope, and curvature. Quantifying REE patterns using independent shape parameters is similar to the use of REE ratios but is an improvement as (1) it uses information from all 14 REE rather than just two; (2) the use of two independent parameters (e.g. slope and curvature) is a more robust discriminant than the use of a single ratio; and (3) subtle variations in shape are easily distinguished enabling trends in the REE patterns of large datasets to be identified. Quantitative models were constructed showing how the shapes of the REE patterns of zircon change due to the co-crystallisation of other metamorphic minerals (monazite, apatite, and garnet). Diagnostic changes in shape enable the REE contents of zircon crystals or crystal zones to be accurately related to the growth of specific minerals and hence metamorphic events. The results were used to interpret the REE patterns of zircons from high-grade metamorphic terranes, which have experienced multiple deformation events (Val Malenco, Italy; Betic Cordillera, Spain; Seram, Indonesia; Lewisian Gneiss Complex, Scotland; Napier Complex, East Antarctica) and clearly identified zircon that crystallised in the presence of garnet. Quantitative comparison enabled zircon that crystallised prior to, synchronously with, or after garnet to be identified. Similar models can be used to interpret the REE patterns of monazite. This allows the relative timing of the growth of these minerals to be accurately constrained, which given the importance of zircon for geochronology and garnet for geobarometry has the potential to provide insights into the evolution of a metamorphic event.Item Open Access Shaping planetary health inequities: the political economy of the Australian growth model(Carfax Publishing, Taylor & Francis Group, 2023-08) Frank, Nicholas; Arthur, Megan; Friel, SharonPlanetary health equity the equitable enjoyment of good health and wellbeing in a sustainable ecosystem is under threat from anthropogenic climate change and economic and social inequities. Driving these major challenges is the global consumptogenic system that encourages excessive production and consumption goods and services that are harming human and planetary health. Growth models lie at the core of the consumptogenic system. This paper examines the sources of economic growth in Australia, the coalitions that sustain this approach politically, and the implications of these dynamics for planetary health equity. Australia's consumption-led growth model is underpinned by a combination of rising house prices and a permissive credit regime. This growth model is supported by a dominant growth coalition of producer interests, elements of organised labour, and property owners. The growth coalition has been able to successfully generate growth model policy convergence between the mainstream political parties. In turn this growth model, and associated growth coalition, has undermined the pursuit of planetary health equity in Australia by incentivising and driving excessive consumption, greenhouse gas emissions, and economic inequality.Item Open Access The DECam Local Volume Exploration Survey Data Release 2(Institute of Physics Publishing, 2022) Drlica-Wagner, Alex; Ferguson, P. S.; Adamow, M; Aguena, M; Allam, S; Andrade-Oliveira, F; Bacon, David; Bechtol, K; Bell, Eric F; Bertin, E; Lidman, ChristopherWe present the second public data release (DR2) from the DECam Local Volume Exploration survey (DELVE). DELVE DR2 combines new DECam observations with archival DECam data from the Dark Energy Survey, the DECam Legacy Survey, and other DECam community programs. DELVE DR2 consists of ∼160,000 exposures that cover >21,000 deg2 of the high-Galactic-latitude (∣b∣ > 10°) sky in four broadband optical/near-infrared filters (g, r, i, z). DELVE DR2 provides point-source and automatic aperture photometry for ∼2.5 billion astronomical sources with a median 5σ point-source depth of g = 24.3, r = 23.9, i = 23.5, and z = 22.8 mag. A region of ∼17,000 deg2 has been imaged in all four filters, providing four-band photometric measurements for ∼618 million astronomical sources. DELVE DR2 covers more than 4 times the area of the previous DELVE data release and contains roughly 5 times as many astronomical objects. DELVE DR2 is publicly available via the NOIRLab Astro Data Lab science platform.Item Embargo In retrospect: Fifty years of C4 photosynthesis(Springer Nature, 2016) Hibberd, Julian; Furbank, RobertItem Open Access Hierarchically Multiscale Vertically Oriented NiFeCo Nanoflakes for Efficient Electrochemical Oxygen Evolution at High Current Densities(Wiley - VCH Verlag GmbH & CO. KGaA, 2024) Riaz, Asim; Fusco, Zelio; Kremer, Felipe; Gupta, Bikesh; Zhang, Doudou; Jagadish, Chennupati; Tan, Hoe; Karuturi, SivaCrucial advancements in versatile catalyst systems capable of achieving high current densities under industrial conditions, bridging the gap between fundamental understanding and practical applications, are pivotal to propel the hydrogen economy forward. In this study, vertically oriented hierarchically multiscale nanoflakes of NiFeCo electrocatalysts are presented, developed by surface modification of a porous substrate with nano-structured nickel. The resulting electrodes achieve remarkably low overpotentials of 139 mV at 10 mAcm−2 and 248 mV at 500 mAcm−2. Further, scaled-up electrodes are implemented in a water-splitting electrolyser device exhibiting a stable voltage of 1.82 V to deliver a constant current density of 500 mA cm−2 for over 17 days. Moreover, the role of the unique structures on electrochemical activity is systematically investigated by fractal analysis, involving computation of structure factors such as Minkowski connectivity, fractal dimension, and porosity using scanning electron microscope images. It is found that such structures offer higher surface area than typical layered double hydroxide structures due to morphological coherence that results in a superhydrophilic surface, while the base Ni layer boosts the charge transfer. This study demonstrates a Ni/NiFeCo(OH)x heterostructure with highly porous morphology, a key to unlocking extremely efficient oxygen evolution reaction activity with exceptional stability. Moreover, fractal analysis is presented as a valuable tool to evaluate the electrochemical performance of catalysts for their structured morphology.Item Embargo Polysilicon Passivating Contacts in Mass Production: The Pursuit of Higher Efficiencies(IEEE, 2023) Zheng , Peiting; Phang, Pheng; Yang, Jie; Wang, Zhao; Chen, Jinjin; Wang, Er-Chien; Stuckelberger, Josua; Sio, Hang; Zhang, Xinyu; MacDonald, Daniel; Jin, HaoThe application of polysilicon passivating contacts in silicon solar cells has significantly increased the solar cell efficiencies in mass production and the technology is experiencing rapid growth in coming years. Commonly applied in the form of n-type doped polysilicon (poly-Si) passivating contacts on the rear surface to minimize parasitic absorption, the effective suppression of metal silicon interface recombination on the rear surface has in turn highlighted the limitations of the front surface boron diffusions. In this work, the optimization of the front surface boron diffusions and selective emitters, enhancement of the screen printing technology, and reduction of the poly-Si layer thickness have been integrated into large area commercial n-type silicon solar cells to reduce the front surface recombination, shading losses and parasitic absorption. The optimization culminated in improved short circuit current density of 42.24 mA/cm2, open circuit voltage of 719.1 mV and fill factor of 83.66%, and an overall independently certified solar cell efficiency of 25.41%. We present an updated model and loss analysis for the champion solar cell, which shows that front surface recombination remains as one of the primary losses. The updated model was utilized to identify the dependence of cell efficiency on surface recombination, contact resistivity and sheet resistance, and the criteria for further optimization of the front surface.