Preprints
Filtering by Subject: Geochemistry
Extensive Olivine Depletion in Archean Greenstone Belts: Evidence from Drill Core and Implications for Natural Hydrogen Generation
Published: 2026-11-13
Subjects: Earth Sciences, Geochemistry, Geology, Mineral Physics
Natural hydrogen models commonly assume that ultramafic rocks in Archean greenstone belts retain olivine for continued serpentinization, but the regional extent of preservation is poorly constrained. We analyze thermal-infrared mineral logs from 18,692 m of ultramafic drill core in 218 Western Australian boreholes. Olivine exceeds a defined spectral threshold in 97% of intrusion-hosted core but [...]
Classifying rock dissolution patterns using reaction persistence length and front velocity
Published: 2026-11-11
Subjects: Earth Sciences, Geochemistry, Hydrology
Acid–rock dissolution in carbonates underpins many natural and engineered subsurface processes. Péclet–Damköhler (Pe–Da) scaling is traditionally used to relate dissolution patterns to reaction kinetics, advection, and diffusion, but it fails to explain contrasting patterns in fluid–rock systems with similar pH. This is because Da does not capture reaction-rate changes along the flow path, and [...]
Contrasting terrestrial and marine sources of isoprenoid and branched glycerol monoalkyl glycerol tetraethers in marine sediments
Published: 2026-11-07
Subjects: Biogeochemistry, Geochemistry, Oceanography
Glycerol dialkyl glycerol tetraethers (GDGTs) are widely used as environmental proxies, yet the sources and environmental significance of the structurally related glycerol monoalkyl glycerol tetraethers (GMGTs) in marine sediments remain poorly constrained. We investigated isoprenoid and branched GMGTs in 16 coastal soils, 62 East China Sea surface sediments, five South China Sea sediment cores, [...]
A National Screening Framework for Critical Mineral Potential and Heavy Metal Hazard in U.S. Mine Waste
Published: 2026-11-07
Subjects: Earth Sciences, Environmental Health and Protection, Environmental Monitoring, Environmental Sciences, Geochemistry, Geology, Natural Resource Economics, Oil, Gas, and Energy, Other Earth Sciences
The U.S. Geological Survey (USGS) National Mine Waste Inventory (NMWI) Version 2.0 provides the first comprehensive national database of mine-waste features across the United States, but it does not directly evaluate their critical-mineral potential or environmental hazard. We linked 1,498 tailings, waste-rock, leach, and slag features at 343 sites to nearby public geochemical observations from [...]
Fertile or Barren: an open benchmark for testing geochemical fertility indices on mineralized and barren mafic-ultramafic intrusions.
Published: 2026-11-03
Subjects: Earth Sciences, Environmental Sciences, Geochemistry, Geology, Natural Resource Economics, Natural Resources Management and Policy, Oil, Gas, and Energy, Physical Sciences and Mathematics, Tectonics and Structure, Volcanology
Magmatic Ni-Cu-PGE sulfide deposits form through a sequence of processes (e.g., magma generation, transport, crustal interaction, sulfur saturation, and sulfide accumulation). These processes can modify whole-rock compositions in different ways, making it challenging to evaluate the geochemical fertility of mafic-ultramafic magmatic intrusions. Several whole-rock fertility indices have been [...]
Residue alkalinity limits microbial leaching of rare earth elements from industrial wastes
Published: 2026-11-02
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Physical Sciences and Mathematics, Sustainability
Microorganisms that make acids can recover rare earth elements from industrial residues such as red mud, coal fly ash, phosphogypsum and electronic waste. Most published studies test one organism on one residue, so their results are hard to transfer. Here we compiled 17 bioleaching studies, covering 10 residues, 5 groups of organisms and 217 runs. We described them all with one physical model, [...]
Lithologic Period Predicts Yttrium Enrichment in Western United States Stream Sediments
Published: 2026-11-01
Subjects: Applied Statistics, Design of Experiments and Sample Surveys, Earth Sciences, Geochemistry, Geology, Physical Sciences and Mathematics, Statistical Methodology, Statistical Models, Statistics and Probability
Screening ground for heavy rare earth prospecting potential at regional scale depends upon archived geochemistry, because favorable intrusive terrain in the western U.S. greatly exceeds what any drilling program could evaluate directly. This research examined whether the lithologic period of intrusive igneous terrain can reliably predict acid-leachable yttrium using only the stream sediment [...]
High-resolution 14C stratigraphy reveals decadal periodicity in stromatolite lamination
Published: 2026-10-30
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Physical Sciences and Mathematics
Stromatolites constitute amongst the oldest evidence for life on Earth and preserve laminated records throughout most of geological time. However, the timescales represented by their lamination remain poorly constrained. Here, we report the first high-resolution 14C dating combined with Bayesian age-depth modelling for three Holocene stromatolites from contrasting depositional environments. The [...]
Prospectivity model for magmatic Nickel, Copper, Cobalt, and Platinum-Group Elements in the Midcontinent Rift
Published: 2026-10-30
Subjects: Earth Sciences, Geochemistry, Geology, Geophysics and Seismology, Volcanology
Much of the Midcontinent Rift is concealed beneath glacial sediment, which limits direct geological observation and makes it difficult to evaluate the potential for undiscovered magmatic Ni–Cu–PGE deposits with publicly available data. The 1.1 Ga rift hosts the Eagle Ni–Cu–PGE deposit of northern Michigan, one of the few domestic sources of nickel, a critical mineral of the United States. We [...]
Triple oxygen isotope equilibrium between calcite and water: new constraints over 8–200 °C and their metrological implications
Published: 2026-10-29
Subjects: Earth Sciences, Geochemistry, Physical Sciences and Mathematics
High-precision measurements of carbonate oxygen-17 compositions are increasingly used for studying paleo-environments, hydrology, diagenesis, or biomineralization processes. Calibrating triple oxygen isotope equilibrium fractionations between calcite and water as a function of temperature provides a critical baseline for many applications. Here we report new observations constraining these [...]
Laboratory Spectroradiometric Temperature Retrieval of Silicates Using Linearized Wien Approximations and Polynomial Regression
Published: 2026-10-27
Subjects: Earth Sciences, Geochemistry, Geophysics and Seismology, Mineral Physics
Thermal infrared (TIR) remote sensing provides critical diagnostic capabilities for surface temperature and spectral emissivity retrieval. However, extracting these parameters from at-target radiance measurements is fundamentally ill-posed because Planck's radiation law non-linearly couples kinetic temperature and spectral emissivity, creating an underdetermined system of N spectral bands with [...]
Contour-crossing calculations quantify decadal changes in the pCO2 impacts of inorganic chemical weathering in the North American Arctic
Published: 2026-10-26
Subjects: Biogeochemistry, Earth Sciences, Geochemistry, Hydrology, Physical Sciences and Mathematics
Degradation of Arctic permafrost is altering biogeochemical dynamics by exposing previously frozen sediment to water, acids, and oxidants. While thaw-driven enhancement of carbonate and silicate mineral weathering results in drawdown of atmospheric carbon dioxide (pCO2), acting as a negative feedback on modern climate change, enhancement of sulfide mineral oxidation increases pCO2 and acts as a [...]
Data-efficient prediction of rare earth leaching from industrial residues with physics-constrained machine learning
Published: 2026-10-25
Subjects: Earth Sciences, Engineering, Geochemistry, Mining Engineering, Physical Sciences and Mathematics
Coal ash, mine-water sludge, red mud and phosphogypsum contain rare earth elements, and each new feedstock needs its own leaching recipe. LixaLearn couples a small neural network to closed-form rate laws for four metal hosts (exchange sites, fast-dissolving minerals, slow-dissolving minerals and a locked fraction), with part of the fast host limited by the solubility of its mineral. The network [...]
From rifting to collision: deep closure of a Wilson cycle during the Archean–Paleoproterozoic transition at the Carajás-Bacajá boundary, Amazonian Craton
Published: 2026-10-22
Subjects: Earth Sciences, Geochemistry, Geology, Tectonics and Structure
The Carajás-Bacajá boundary preserves complementary archives of continental rifting, passive-margin development, subduction, collision and post-collisional exhumation across the Archean-Paleoproterozoic transition. We present whole-rock lithogeochemistry, Sm-Nd isotopes, U-Pb zircon geochronology and thermobarometry from the Vila Santa Fé-Rio Preto association, a mafic-felsic granulitic [...]
Decoupling ore formation, ductile fabric and hydrothermal upgrading in the giant Salobo IOCG deposit, Carajás Province, Brazil
Published: 2026-10-22
Subjects: Earth Sciences, Geochemistry, Geology, Tectonics and Structure
The Salobo deposit is the largest Cu-Au deposit of the Carajás Mineral Province, northern Brazil, and is hosted by altered volcanosedimentary schists of the Itacaiúnas Supergroup along the Cinzento Lineament. Multiscale structural analysis, mineral chemistry and published geochronology define four structural families: Pre-Dn, Dn, Dn+1 and Dn+2. The Pre-Dn event comprises high-temperature K, K-Fe [...]