Geoscience Australia

Abstract Characterizing carbonate aquifers presents significant challenges, especially when it involves determining groundwater flow zones at the field scale. The combination of seismic data and well logs, along with a suitable processing approach, supports this effort. We processed high-resolution reflection seismic data obtained from the Port Mayaca aquifer, located in Martin County, South Florida. We applied a forward solution algorithm to invert this data for impedance. The resulting images displayed anomalies associated with dense, tight limestone layers. These anomalies, combined with Formation MicroImager (FMI) data and micro-resistivity logs, lead to the existence of fractures. To enhance our analysis, we applied an artificial neural network (ANN) using seismic attributes from the seismic waveforms and the impedance data. The initial image produced by the ANN algorithm illustrates the pore space based on the aspect ratio log, which serves as the target data for the neural network model. The Python library Keras provided the framework needed to develop these network models. The application of the Keras software allows us to create images of pore aspect ratio, Stoneley (ST) wave permeability, and intrinsic permeability. The interpretation and analysis of these images revealed the connectivity of the pore space between narrow and wide channels, as well as the flow paths linked to the permeable zones. The ST wave permeability image highlights the major flow zones present in the inter-well region. The results of the data analysis demonstrate that a flow zone structure, defined by the aspect ratio, is part of a groundwater channel. We found that a permeable zone identified in the ST permeability image represents the total flow created by the interconnected vugs and fractures. We generated ELAN intrinsic permeability images to examine the aquifer’s pore structure, and we found that the areas with low-intrinsic permeability correlate with locations of dense, fractured limestone layers.

Over recent decades, strides have been made towards increasing the representation of underrepresented groups in geosciences. Nevertheless, notable disparities remain in prestige academic roles, defined here as journal editorial boards, conference organizing committees, and society boards, particularly concerning gender and geographic diversity. Focusing on the subdiscipline of coastal geoscience and engineering, this study evaluates current gender and geographic representation in these prestige roles, measures the progress rate in female representation, and explores strategies to close diversity gaps. Our findings indicate that women and individuals from the global south are underrepresented in these roles compared to their presence in professional society memberships or journal contributions. Although the representation of women in prestigious roles often showed improvement in 2024 compared to 2016, it still falls below the average representation of women in 2024. If current trends persist, only 20% of journal boards are projected to attain gender parity within the next ten years, while over half may regress or take over a century to achieve parity. Survey results reveal substantial variability in recruitment practices, with few organizations actively prioritizing diversity through efforts to achieve geographic representation and gender balance. We leverage these findings to provide actionable recommendations for improving recruitment strategies for prestige roles, stressing the importance of diversity as a catalyst for reduced bias, enhanced creativity, and increased rates of innovation. Ongoing monitoring of minority group representation within academic prestige roles is required to document the success of initiatives to secure continued progress towards equitable representation.

Intracontinental reverse faults in Otago and South Canterbury, Aotearoa-New Zealand, have complex surface morphologies. The Dunstan Fault and Fox Peak Fault are expressed at the surface by multiple parallel to sub-parallel fault traces. These traces can be hundreds of meters apart from each other and span a deformation zone up to 2-3km in width. We ask the following questions: Do all traces rupture together in each ground rupturing earthquake, or do they rupture independently? If traces rupture independently, is it random which trace ruptures in a given event, or is there a spatio-temporal pattern? What is the likelihood of a new trace rupturing in the next large earthquake? We use paleoseismic techniques to constrain the timings of past earthquakes on each trace. The results are compared to see if the same earthquake ruptured multiple traces. If we can tease out any spatio-temporal patterns, we may be able to answer the question: In a future ground rupturing earthquake, which trace/traces will rupture? The results have implications for fault zonation and fault displacement hazard analysis of intracontinental reverse faults in Aotearoa-New Zealand and beyond.

The rapid uptake in photovoltaics (PV) over the last few decades has substantially reduced the cost of their main component — the PV module. As a result, other direct and indirect costs are becoming significant expenses in new solar projects. Nevertheless, although comparisons are often made between costs and performance at a system-level, the role and variability of location-dependent expenses (such as transport and labor) on the final costs of solar power is less widely discussed. In this paper, we evaluate the levelized cost of electricity for utility-scale solar farms across Australia. The performance of conventional PV systems featuring bi-facial glass-based crystalline silicon modules is compared to novel configurations that utilize lightweight crystalline silicon modules. For this comparison, we introduce a new method that maps the levelized cost of electricity for installed PV, accounting for differences in panel, balance-of-system, installation and transportation costs, as well as the system’s yield. The results indicate that novel lightweight PV systems show a competitive advantage in remote areas where labor and transportation costs are increased, while reduced prices of the modules and extended lifespans for the lightweight PV systems can make such technologies competitive across the whole country. • A geospatial mapping approach for LCOE produced by photovoltaics is introduced. • The approach is applied to Australia, comparing glass-based and lightweight PV. • The sensitivity of intra-regional, location-dependent costs are explored. • Conventional PV systems are currently the most viable technology across Australia. • Cost reductions and increases in lifetimes will enhance viability of lightweight PV.

Australia's Antimony Supply Chain is a national snapshot of the antimony sector as of January 2026 including production, resources and exploration.<br>Antimony is a critical mineral essential for energy, defence and advanced manufacturing applications. While its traditional demand has come from flame retardants and lead‑acid batteries, consumption in these legacy sectors is declining due to material substitution, modern alloying practices, and the shift to lithium-ion batteries. Increasing recycling rates are meeting most metallurgical demand (e.g. lead-acid batteries), meaning primary supply growth is now tied largely to non-metallurgical, technology-driven uses. Antimony use in solar photovoltaic glass has expanded rapidly, and it continues to play an important role in electronics and certain semiconductor applications. Strategic applications include use in ammunition.

Summary Induced polarization (IP) effects in airborne electromagnetic (AEM) surveys have commonly been investigated in helicopter-borne systems, leaving both a bibliographic and application gap for fixed-wing configurations. This gap partly reflects the large relative number of helicopter compared to fixed wing AEM systems, but also the geometric complexity of fixed wing platforms. In these platforms, nine geometric parameters come into play: the pitch, roll, and yaw of both transmitter and receiver, plus the three-axis offsets between the coils. Shifts in these factors can distort the measured data in ways that aren’t uniquely attributable, making it hard to pinpoint whether negative recordings truly arise from IP or from geometry-related effects. The non-fixed geometry also complicates removal of the primary field, often requiring iterative processing steps that may suppress or alter spectral content linked to IP. With advances in airborne IP understanding from helicopter-borne systems, revisiting fixed-wing platforms is both timely and necessary. Part A of this two-part study addresses this issue using the TEMPEST™ fixed-wing system connecting numerical modelling with field evidence. A suite of synthetic two-layer models with variable resistivity and chargeability parameters was developed to evaluate the system’s sensitivity to polarizable structures. The experiments demonstrate that IP effects, including negative secondary field responses, can be reliably detected in fixed-wing AEM data, both in X and Z magnetic field components. The capacity of these systems to detect IP phenomena is, however, strongly dependent on the electrical conductance of the environment. For instance, both fixed-wing and helicopter-borne systems, elevated near-surface conductance enhances the amplitude of purely electromagnetic induction currents, which in turn can dominate the recorded response and obscure the comparatively weaker polarization currents. More in general, IP detectability depends on the strength of the EM response generated by induction currents flowing elsewhere, which can dominate the small reverse current flow from a polarizable target. This highlights the critical role of near-surface conductivity in controlling the expression of IP responses and underscores the need to carefully account for these factors when interpreting survey data. The synthetic results are then connected with field-scale observations from a subset of the AusAEM dataset, over 470 000 line-km of TEMPESTTM data, where negative responses align with areas of low shallow conductance, confirming the simulation results. These finding open the way to the Part B of this study, where TEMPESTTM data are inverted taking into account IP and compared with helicopter-borne results and geological information.

Abstract. Chemical abrasion (CA), a two-step process of annealing and partial dissolution, is routinely applied to zircon grains prior to U–Pb geochronology to dissolve portions of the grains affected by Pb loss prior to analysis. Despite the utility of the technique, it is not clear what the more HF-soluble material produced in the annealing step is, what degree of lattice damage causes it to form instead of zircon, how to predict if a specific sub-volume of a zircon will survive CA, or how any of these processes relate to Pb mobility. In this study, we use secondary ion mass spectrometry (SIMS), Raman spectroscopy, and atom probe tomography (APT) to constrain what happens to both concordant and discordant zircon during each step of the CA process. We find that zircon in SIMS sputter craters which have undergone Pb loss generally have more heterogeneous Raman band widths than in those sputter craters where Pb has been retained. Annealing drastically reduces Raman band widths, but some heterogeneity is still present in discordant sputter craters. APT results from all samples which successfully ran were homogeneous in U, Pb, Th, and most other elements in all cases. This makes it hard to link Pb loss and lattice damage at the submicrometre scale by direct imaging in this study. However, as the zircon sputter craters with Pb loss show homogeneous APT results, we recommend against using homogeneous APT results as an indicator of closed-system U–Pb behaviour.

<strong class="journal-contentHeaderColor">Abstract.</strong> The bottom mixed layer (BML) of the abyssal ocean regulates heat exchange between the deep interior and seafloor, driving water-mass transformation and influencing global circulation. Spatial variability of the BML was examined in the under-sampled abyssal Pacific Ocean using surface-to-seafloor temperature and pressure observations over 4 months in 2023&ndash;24. Given the typical decadal repeat rate of global hydrographic sections, subdecadal variability in the abyssal ocean has remained poorly resolved. While constrained in coverage, our observations contribute towards filling this gap for the central and eastern abyssal Pacific Ocean. Four methods were used to determine the BML thickness, with the threshold method providing the most reliable estimates. The mean BML thickness was 226 &plusmn; 172 with added repeat hydrographic sections providing context and additional data points. At each BML data point we determined the slope, the terrain roughness and the extracted predicted internal tide energy dissipation (over five different low-mode processes and high-mode local processes) at 50 km scales from publicly available datasets. These factors were input into a Random Forest Regressor (RF) model, the first time machine learning techniques have been applied to investigate BML thickness. The RF feature importance scores identified bottom depth, total internal tide energy dissipation, followed by slope, as the strongest predictors of BML thickness, revealing the importance of low-mode internal wave energy losses in this abyssal setting. Targeted and sustained observations near the seafloor at gateway regions of abyssal pathways are vital for understanding energy exchange that influences meridional overturning circulation. Our results highlight a regime where sustained low-mode internal tide energy loss, modulated by topographic slope and depth, governs the BML thickness in the abyssal Pacific. However, the rate at which BML thickness changes over time and the processes that cause these changes remain key unresolved factors.