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Global warming has caused widespread surface lowering of mountain glaciers. By comparing two firn cores collected in 2018 and 2020 from Corbassière glacier in Switzerland, we demonstrate how vulnerable these precious archives of past environmental conditions have become. Within two years, the soluble impurity records were destroyed by melting. The glacier is now irrevocably lost as an archive for reconstructing major atmospheric aerosol components. Information on past environmental conditions stored within high-altitude glaciers is being lost due to accelerated melting associated with climate change, according to ice core analysis from a Swiss glacier.

In 2015, a continuous 15.4 m snow/firn core was recovered from central South Georgia Island at ∼850 m a.s.l. All firn core samples were analyzed for major (Al, Ca, Mg, Na, K, Ti and Fe) and trace element concentrations (Sr, Cd, Cs, Ba, La, Ce, Pr, Pb, Bi, U, As, Li, S, V, Cr, Mn, Co, Cu and Zn) and stable water isotopes. The chemical and isotopic signal is well preserved in the top 6.2 m of the core. Below this depth, down to the bottom of the core, signal dampening is observed in the majority of the elemental species making it difficult to distinguish a seasonal signal. Thirteen elements (As, Bi, Ca, Cd, Cu, K, Li, Mg, Na, Pb, S, Sr and Zn) have crustal enrichment factor values higher than 10 suggesting sources in addition to those found naturally in the crust. While this study shows that 850 m a.s.l. is not high enough to preserve a record including recent years, higher-elevation (>1250 m a.s.l.) glaciers may be likely candidates for ice core drilling to recover better-preserved, continuous, recent to past glaciochemical records.

Wetlands, critical yet vulnerable ecosystems worldwide, are increasingly threatened by contamination from anthropogenic activities. This study investigates the spatial and vertical distribution of 17 major and trace elements in sediment cores from the Anzali International Wetland, a Ramsar site in Iran under pressure from urbanization, agriculture, and industry. Cores were sliced at 2-cm intervals and analyzed via ICP-MS to reconstruct historical trends and evaluate spatiotemporal distributions, sources, and ecological risks using geoaccumulation index (I geo ), enrichment factor (EF), and pollution load index (PLI). Multivariate analyses (PCA, HCA) identified lithogenic (Al, Fe), carbonate-associated (Ca, Sr), and anthropogenic (Cd, Pb, Zn) elemental groupings. Severe Cd contamination (I geo > 5; EF > 40) was found at site 1, linked to industrial/agricultural discharges, while sites 2 and 3 showed moderate heavy metal enrichment. Cd, Cr, and Ni exceeded sediment quality guidelines, indicating significant ecological risk. Vertical profiles revealed contamination peaks at 24–26 cm (Site 1) and 50–62 cm (Site 2), correlating with historical pollutant influx. Sediment texture and organic matter influenced metal binding. PLI confirmed significant pollution (PLI > 3) across all sites, with Cd posing the highest risk. This study underscores the critical role of integrated sediment core analysis in reconstructing pollution history and informing targeted management strategies to protect and restore vulnerable aquatic ecosystems globally.

Ice crystals are mechanically and dielectrically anisotropic. They progressively align under cumulative deformation, forming an ice-crystal-orientation fabric that, in turn, impacts ice deformation. However, almost all the observations of ice fabric are from ice core analysis, and its influence on the ice flow is unclear. Here, we present a non-linear inverse approach to process co- and cross-polarized phase-sensitive radar data. We estimate the continuous depth profile of georeferenced ice fabric orientation along with the reflection ratio and horizontal anisotropy of the ice column. Our method approximates the complete second-order orientation tensor and all the ice fabric eigenvalues. As a result, we infer the vertical ice fabric anisotropy, which is an essential factor to better understand ice deformation using anisotropic ice flow models. The approach is validated at two Antarctic ice core sites (EPICA (European Project for Ice Coring in Antarctica) Dome C and EPICA Dronning Maud Land) in contrasting flow regimes. Spatial variability in ice fabric characteristics in the dome-to-flank transition near Dome C is quantified with 20 more sites located along with a 36 km long cross-section. Local horizontal anisotropy increases under the dome summit and decreases away from the dome summit. We suggest that this is a consequence of the non-linear rheology of ice, also known as the Raymond effect. On larger spatial scales, horizontal anisotropy increases with increasing distance from the dome. At most of the sites, the main driver of ice fabric evolution is vertical compression, yet our data show that the horizontal distribution of the ice fabric is consistent with the present horizontal flow. This method uses polarimetric-radar data, which are suitable for profiling radar applications and are able to constrain ice fabric distribution on a spatial scale comparable to ice flow observations and models.

Direct pore scale simulations of two-fluid flow on digital rock images provide a promising tool to understand the role of surface wetting phenomena on flow and transport in geologic reservoirs. We present computational protocols that mimic conventional special core analysis laboratory (SCAL) experiments, which are implemented within the open source LBPM software package. Protocols are described to simulate unsteady displacement, steady-state flow at fixed saturation, and to mimic centrifuge experiments. These methods can be used to infer relative permeability and capillary curves, and otherwise understand two-fluid flow behavior based on first principles. Morphological tools are applied to assess image resolution, establish initial conditions, and instantiate surface wetting maps based on the distribution of fluids. Internal analysis tools are described that measure essential aspects of two-fluid flow, including fluid connectivity and surface measures, which are used to track transient aspects of the flow behavior as they occur during simulation. Computationally efficient workflows are developed by combining these components with a two-fluid lattice Boltzmann model to define hybrid methods that can accelerate computations by using morphological tools to incrementally evolve the pore-scale fluid distribution. We show that the described methods can be applied to recover expected trends due to the surface wetting properties based on flow simulation in Benntheimer sandstone.

We construct a high‐resolution shear‐wave velocity (VS) model for the uppermost 100 m using ambient noise tomography near the West Antarctic Ice Sheet Divide camp. This is achieved via joint inversion of Rayleigh wave phase velocity and H/V ratio, whose signal‐to‐noise ratios are boosted by three‐station interferometry and phase‐matched filtering, respectively. The VS shows a steep increase (0.04–0.9 km/s) in the top 5 m, with sharp interfaces at ∼8–12 m, followed by a gradual increase (1.2–1.8 km/s) between 10 and 45 m depth, and to 2 km/s at ∼65 m. The compressional‐wave velocity and empirically‐obtained density profile compares well with the results from Herglotz–Wiechert inversion of diving waves in active‐source shot experiments and ice core analysis. Our approach offers a tool to characterize high‐resolution properties of the firn and shallow ice column, which helps to infer the physical properties of deeper ice sheets, thereby contributes to improved understanding of Earth's cryosphere. Plain Language Summary Accurately determining the physical properties of Antarctic ice sheets enhances our understanding of climate change impacts on the Earth's cryosphere and improves sea level rise predictions. The uppermost ∼100 m of ice sheets are often covered by firn, an intermediate material between fresh granular snow and glacier ice. Firn acts as a buffer between the atmosphere and deep ice, playing a critical role in the mass balance, flow, and dynamics of the ice sheet. In this study, we use advanced techniques to measure seismic velocities of the top ∼100 m of the ice sheet and thus characterize the properties of the firn layer. Using a week‐long record of seismic ambient noise, we obtain velocity models that reveal the detailed structure of the firn layer, including rapid velocity increases over depth that indicate rapid changes in compaction and slight lateral velocity variations. These models were validated through favorable comparisons to conventional analyses and ice core records, and can be used to estimate other important ice properties (e.g., density) via empirical relationships. Our approach could easily be up‐scaled to long‐term monitoring of larger areas, to help inform predictive models of ice sheet dynamics. Key Points We denoise fundamental‐mode Rayleigh waves extracted from ambient noise recorded in West Antarctic via three‐station interferometry We improve the quality of Rayleigh wave H/V ratio measurements with phase‐matched filtering The high‐resolution Vs model obtained by jointly inverting phase velocities and H/V ratios reveals high‐resolution firn structures

This study presents an integrated formation evaluation of the Middle Miocene syn-rift sandstones of the Hammam Faraun Member from the southern Gulf of Suez. Core data, XRD, wireline logs, and gas chromatography data have been utilized to assess the reservoir characteristics. Three lithofacies are identified from the cored intervals: (i) fine to medium-grained massive sandstone (F-1), (ii) low-angle cross-bedded fine-grained sandstone (F-2); and (iii) coarse to very coarse-grained massive sandstone (F-3). The dominantly massive nature of the sand units with sharp erosive base and bottom rip-up clasts strongly indicates a high energy channel or fan deposit. XRD analysis reveals quartz and feldspar to be the dominant constituents of this calcareous arkose. Montmorillonite and kaolinite are the major clay phases, along with minor illite. Routine core analysis of a total of 168 core plugs indicates meso- to megaporous sandstones with porosity up to 28% and Kh up to 1171 mD. Permeability anisotropy analysis exhibits the dominance of primary depositional fabric and isotropic pores. Wireline log analysis yielded shale volume < 0.2 v/v, porosity ~ 0.18–0.24 v/v, and water saturation ~ 0.33–0.49 v/v. Various gas ratios (wetness, balance, character, and oil indicator ratio) estimated from the chromatograph data indicate the presence of liquid hydrocarbons within the studied reservoirs. The study concludes excellent reservoir properties in the Hammam Faraun clastic intervals of the Esh El Mellaha area.HighlightsHammam Faraun reservoirs consist of meso-megaporous calcareous arkose.Massive sands with sharp erosive base and bottom rip-up clasts indicates a high energy tidal deposit.Wireline logs indicate poor shale volume and considerable hydrocarbon saturation.Gas chromatography data confirms the presence of liquid hydrocarbon.

Current volcanic reconstructions based on ice core analysis have significantly improved over the past few decades by incorporating multiple-core analyses with a high temporal resolution from different parts of the polar regions into a composite common volcanic eruption record. Regional patterns of volcanic deposition are based on composite records, built from cores taken at both poles. However, in many cases only a single record at a given site is used for these reconstructions. This assumes that transport and regional meteorological patterns are the only source of the dispersion of the volcanic products. Here we evaluate the local-scale variability of a sulfate profile in a low-accumulation site (Dome C, Antarctica), in order to assess the representativeness of one core for such a reconstruction. We evaluate the variability with depth, statistical occurrence, and sulfate flux deposition variability of volcanic eruptions detected in five ice cores, drilled 1 m apart from each other. Local-scale variability, essentially attributed to snow drift and surface roughness at Dome C, can lead to a non-exhaustive record of volcanic events when a single core is used as the site reference, with a bulk probability of 30 % of missing volcanic events and close to 65 % uncertainty on one volcanic flux measurement (based on the standard deviation obtained from a five-core comparison). Averaging n records reduces the uncertainty of the deposited flux mean significantly (by a factor 1∕ √ n); in the case of five cores, the uncertainty of the mean flux can therefore be reduced to 29 %.

Digital rock physics (DRP) has undergone significant advancements in the use of various imaging techniques to acquire three-dimensional volumes and images of rock samples for the computation of petrophysical properties. This study focuses on developing a DRP workflow using high-resolution thin section scans for computing porosity and permeability in cuttings samples. The workflow was tested on quarry sandstone plug samples and artificially generated pseudo-cuttings before applying it to real cuttings from oil and gas wells. The results show that the porosity and permeability values obtained through the DRP workflow are statistically equivalent to those obtained through conventional routine core analysis (RCAL). The workflow was also able to handle the presence of various lithologies in real cuttings samples. The study demonstrates the feasibility of obtaining porosity and permeability values in cutting samples using the DRP approach, offering a fast and cost-effective methodology that provides additional data and allows linking petrophysical properties to image data from the cuttings.

The record of past greenhouse gas composition from ice cores is crucial for our understanding of global climate change. Future ice core projects will aim to extend both the temporal coverage (extending the timescale to 1.5 Myr) and the temporal resolution of existing records. This implies a strongly limited sample availability, increasing demands on analytical accuracy and precision, and the need to reuse air samples extracted from ice cores for multiple gas analyses. To meet these requirements, we designed and developed a new analytical system that combines direct absorption laser spectroscopy in the mid-infrared (mid-IR) with a quantitative sublimation extraction method. Here, we focus on a high-precision dual-laser spectrometer for the simultaneous measurement of CH4, N2O, and CO2 concentrations, as well as δ13C(CO2). Flow-through experiments at 5 mbar gas pressure demonstrate an analytical precision (1 σ) of 0.006 ppm for CO2, 0.02 ‰ for δ13C(CO2), 0.4 ppb for CH4, and 0.1 ppb for N2O, obtained after an integration time of 100 s. Sample–standard repeatabilities (1 σ) of discrete samples of 1 mL STP (Standard Temperature and Pressure) amount to 0.03 ppm, 2.2 ppb, 1 ppb, and 0.04 ‰ for CO2, CH4, N2O, and δ13C(CO2), respectively. The key elements to achieve this performance are a custom-developed multipass absorption cell, custom-made high-performance data acquisition and laser driving electronics, and a robust calibration approach involving multiple reference gases. The assessment of the spectrometer capabilities in repeated measurement cycles of discrete air samples – mimicking the procedure for external samples such as air samples from ice cores – was found to fully meet our performance criteria for future ice core analysis. Finally, this non-consumptive method allows the reuse of the precious gas samples for further analysis, which creates new opportunities in ice core science.