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The Fisher Valley basin (FVB), located adjacent to the Onion Creek salt diapir, Paradox basin, Utah, USA, constitutes one of the thickest collections of Quaternary sediments within the Colorado Plateau. These sediments are important for constraining regional paleoclimate environments as well as recent tectonic movement of the Onion Creek salt diapir. Here, we combine magnetic susceptibility data with previously published age constraints (Bishop Tuff and Lava Creek B ash) into a cyclostratigraphic analysis of these sediments. We present a refined and astronomically tuned age model that demonstrates that deposition of the upper basin fill was between ca. 765 ka and 212 ± 8 ka. Correlating this chronologic model to environmental magnetic proxies, we show that from ca. 765 ka to ca. 535 ka, magnetic mineral assemblages deposited during glacials were characterized by generally finer grain sizes (elevated χARM/χlow) than during interglacials. These data are consistent with glacial periods being characterized by either wetter conditions amenable to pedogenesis, or drier conditions associated with increased concentrations of windblown dust. Interglacials are characterized by generally coarser magnetic grain sizes (lower χARM/χlow), consistent with periods of episodic alluvial and colluvial deposition in the FVB. At ca. 535 ka, χARM/χlow reach their lowest value (coarsest magnetic grain size) and then begin a progressive transition to higher values, consistent with a generally fining upward stratigraphic sequence throughout the rest of the section. This transition at ca. 535 ka coincides with a peak in sediment accumulation rate of ∼19 cm/k.y. and is most plausibly linked to halokinetic activity of the nearby Onion Creek salt diapir. Thus, although sediments in the FVB appear to be sensitive to global climate patterns between 765 ka and ca. 535 ka, local tectonic processes appear to episodically obscure this sensitivity. 

ABSTRACT Microorganisms are important catalysts for the oxidation of reduced inorganic sulfur compounds. One environmentally important source of reduced sulfur is metal sulfide minerals that occur in economic mineral deposits and mine waste. Previous research found thatSulfuriferulaspp. were abundant and active in long-term weathering experiments with simulated waste rock and tailings from the Duluth Complex, Northern Minnesota. We, therefore, isolated several strains ofSulfuriferulaspp. from these long-term experiments and characterized their metabolic and genomic properties to provide insight into microbe-mineral interactions and the microbial biogeochemistry in these and other moderately acidic to circumneutral environments. TheSulfuriferulastrains are all obligate chemolithoautotrophs capable of oxidizing inorganic sulfur compounds and ferrous iron. The strains grew over different pH ranges, but all grew between pH 4.5 and 7, matching the weathering conditions of the Duluth Complex rocks. All strains grew on the iron-sulfide mineral pyrrhotite (Fe_{1 −x}S, 0 <x< 0.125) as the sole energy source, as well as hydrogen sulfide and thiosulfate, which are products of sulfide mineral breakdown. Despite their metabolic similarities, each strain encodes a distinct pathway for the oxidation of reduced inorganic sulfur compounds as well as differences in nitrogen metabolism that reveal diverse genomic capabilities among the group. Our results show thatSulfuriferulaspp. are primary producers that likely play a role in sulfide mineral breakdown in moderately acidic to circumneutral mine waste, and the metabolic diversity within the genus may explain their success in sulfide mineral-rich and other sulfidic environments. IMPORTANCEMetal sulfide minerals, such as pyrite and pyrrhotite, are one of the main sources of reduced sulfur in the global sulfur cycle. The chemolithotrophic microorganisms that break down these minerals in natural and engineered settings are catalysts for biogeochemical sulfur cycling and have important applications in biotechnological processes such as biomining and bioremediation.Sulfuriferulais a recently described genus of sulfur-oxidizing bacteria that are abundant primary producers in diverse terrestrial environments, including waste rock and tailings from metal mining operations. In this study, we explored the genomic and metabolic properties of new isolates from this genus, and the implications for their ecophysiology and biotechnological potential in ore and waste from economic mineral deposits. 

Reaction of a model nitroaromatic pollutant with hematite-coated sand in column reactors leads to growth of goethite and evolving reactivity due to changes in accessible surface area. 

Geomagnetic methods allow us to explore the behavior of Earth's geodynamo, constrain Earth's composition and structure, and locate critical minerals and other resources essential for modern technologies and the energy transition. The magnetic properties of rocks and sediments are assumed to be stable and largely attributable to inorganic processes. This conventional view overlooks mounting evidence of microorganisms as key players in rock transformations and geological processes. Iron-bearing minerals are ubiquitous in most environments and are commonly used by microorganisms as electron donors and acceptors. Microorganisms modulate rock magnetic properties by creating, altering, and dissolving Fe-bearing minerals, potentially modifying the original magnetization, complicating interpretations of the magnetic record. This review provides an overview of biogenic pathways that modulate magnetic minerals and discusses common, yet underutilized, magnetic methods for capturing such behavior. Appreciating the influence of microbial activities on magnetic properties will improve our interpretations of Earth's geologic past and its elemental cycling.▪Microorganisms modulate rock magnetic properties, challenging traditional views of a geologically stable magnetic record formed solely by inorganic processes.▪Microbial iron cycling modulates magnetic properties modifying magnetic information recorded in rocks.▪Microbial processes may have impacted Earth's magnetic history more deeply than previously understood.▪Recognizing microbial contributions is critical for accurate interpretation of paleomagnetic and environmental magnetic records and could aid in the search for life on other planetary bodies. 

Abstract Speleothems are mineral deposits capable of recording detrital and/or chemical remanent magnetization at annual timescales. They can offer high‐resolution paleomagnetic records of short‐term variations in Earth's magnetic field, crucial for understanding the evolution of the dynamo. Owing to limitations on the magnetic moment sensitivity of commercial cryogenic rock magnetometers (∼10⁻¹¹ Am²), paleomagnetic studies of speleothems have been limited to samples with volumes of several hundreds of mm³, averaging tens to hundreds of years of magnetic variation. Nonetheless, smaller samples (∼1–10 mm³) can be measured using superconducting quantum interference device (SQUID) microscopy, with a sensitivity better than ∼10⁻¹⁵ Am². To determine the application of SQUID microscopy for obtaining robust high‐resolution records from small‐volume speleothem samples, we analyzed three different stalagmites collected from Lapa dos Morcegos Cave (Portugal), Pau d'Alho Cave (Brazil), and Crevice Cave (United States). These stalagmites are representative of a range of magnetic properties and have been previously studied with conventional rock magnetometers. We show that by using SQUID microscopy we can achieve a five‐fold improvement in temporal resolution for samples with higher abundances of magnetic carriers (e.g., Pau d'Alho Cave and Lapa dos Morcegos Cave). In contrast, speleothems with low abundances of magnetic carriers (e.g., Crevice Cave) do not benefit from higher resolution analysis and are best analyzed using conventional rock magnetometers. Overall, by targeting speleothem samples with high concentrations of magnetic carriers we can increase the temporal resolution of magnetic records, setting the stage for resolving geomagnetic variations at short time scales. 

Abstract The Duluth Complex (DC) contains sulfide‐rich magmatic intrusions that represent one of the largest known economic deposits of copper, nickel, and platinum group elements. Previous work showed that microbial communities associated with experimentally‐weathered DC waste rock and tailings were dominated by uncultivated taxa and organisms not typically associated with mine waste. However, those experiments were designed for kinetic testing and do not necessarily represent the conditions expected for long‐term environmental weathering. We used 16S rRNA gene methods to characterize the microbial communities present on the surfaces of naturally‐weathered and historically disturbed outcrops of DC material. Rock surfaces were dominated by diverse unculturedKtedonobacteria,Acetobacteria, andActinobacteria, with abundant algae and other phototrophs. These communities were distinct from microbial assemblages from experimentally‐weathered DC rocks, suggesting different energy and nutrient resources in environmental samples. Sulfide mineral incubations performed with and without algae showed that photosynthetic microorganisms could have an inhibitory effect on autotrophic populations, resulting in slightly lower sulfate release and differences in dominant microorganisms. The microbial assemblages from these weathered outcrops show how communities develop during weathering of sulfide‐rich DC rocks and represent baseline data that could evaluate the effectiveness of future reclamation of waste produced by large‐scale mining operations. 

Abstract. The upper Paleozoic Cutler Group of southern Utah, USA, is a key sedimentary archive for understanding the Earth-life effects of the planet's last pre-Quaternary icehouse–hothouse state change: the Carboniferous–Permian (C–P) transition, between 304 and 290 million years ago. Within the near-paleoequatorial Cutler Group, this transition corresponds to a large-scale aridification trend, loss of aquatic habitats, and ecological shifts toward more terrestrial biota as recorded by its fossil assemblages. However, fundamental questions persist. (1) Did continental drift or shorter-term changes in glacio-eustasy, potentially driven by orbital (Milankovitch) cycles, influence environmental change at near-equatorial latitudes during the C–P climatic transition? (2) What influence did the C–P climatic transition have on the evolution of terrestrial ecosystems and on the diversity and trophic structures of terrestrial vertebrate communities? The Paleozoic Equatorial Records of Melting Ice Ages (PERMIA) project seeks to resolve these issues in part by studying the Elk Ridge no. 1 (ER-1) core, complemented by outcrop studies. This legacy core, collected in 1981 within what is now Bears Ears National Monument, recovered a significant portion of the Hermosa Group and the overlying lower Cutler Group, making it an ideal archive for studying paleoenvironmental change during the C–P transition. As part of this project, the uppermost ∼ 450 m of the core were temporarily transferred from the Austin Core Repository Center to the Continental Scientific Drilling Facility at the University of Minnesota for splitting, imaging, and scanning for geophysical properties and spectrophotometry. Here we (1) review the history of this legacy core, (2) introduce recently obtained geophysical and lithologic datasets based on newly split and imaged core segments to provide a sedimentological and stratigraphic overview of the Elk Ridge no. 1 core that aligns more accurately with the currently recognized regional lithostratigraphic framework, (3) establish the position of the boundary between the lower Cutler beds and the overlying Cedar Mesa Sandstone in the core, and (4) outline our ongoing research goals for the core. In-progress work on the core aims to refine biostratigraphic and chemostratigraphic age constraints, retrieve the polarity stratigraphy, interrogate preserved cyclostratigraphy, analyze sedimentary structures and paleosol facies, investigate stable isotope geochemistry, and evaluate elemental abundance data from X-ray fluorescence (XRF) scanning. Together with outcrop studies throughout Bears Ears National Monument and its vicinity, these cores will allow the rich paleontological and paleoenvironmental archives recorded in the continental Carboniferous–Permian transition of western North America to be confidently placed in a robust chronologic context that will help test hypotheses relating ecosystem evolution to the Carboniferous rainforest collapse, initial decline of the Late Paleozoic Ice Age, and long-wavelength astronomical cycles pacing global environmental change. 

Abstract. Mineral specific surface area (SSA) increases as primaryminerals weather and restructure into secondary phyllosilicate, oxide, andoxyhydroxide minerals. SSA is a measurable property that captures cumulativeeffects of many physical and chemical weathering processes in a singlemeasurement and has meaningful implications for many soil processes,including water-holding capacity and nutrient availability. Here we reportour measurements of SSA and mineralogy of two 21 m deep SSA profiles attwo landscape positions, in which the emergence of a very small mass percent(<0.1 %) of secondary oxide generated 36 %–81 % of the total SSAin both drill cores. The SSA transition occurred near 3 m at bothlocations and did not coincide with the boundary of soil to weathered rock. The3 m boundary in each weathering profile coincides with the depth extentof secondary iron oxide minerals and secondary phyllosilicates. Althoughelemental depletions in both profiles extend to 7 and 10 m depth, themineralogical changes did not result in SSA increase until 3 m depth. Theemergence of secondary oxide minerals at 3 m suggests that this boundary may bethe depth extent of oxidation weathering reactions. Our results suggest thatoxidation weathering reactions may be the primary limitation in thecoevolution of both secondary silicate and secondary oxide minerals. Wevalue element depletion profiles to understand weathering, but our findingof nested weathering fronts driven by different chemical processes (e.g.,oxidation to 3 m and acid dissolution to 10 m) warrants the recognition thatelement depletion profiles are not able to identify the full set ofprocesses that occur in weathering profiles. 

Abstract A key objective of the Perseverance rover mission is to acquire samples of Martian rocks for future return to Earth. Eventual laboratory analyses of these samples would address key questions about the evolution of the Martian climate, interior, and habitability. Many such investigations would benefit greatly from samples of Martian bedrock that are oriented in absolute Martian geographic coordinates. However, the Mars 2020 mission was designed without a requirement for orienting the samples. Here we describe a methodology that we developed for orienting rover drill cores in the Martian geographic frame and its application to Perseverance's first 20 rock samples. To orient the cores, three angles were measured: the azimuth and hade of the core pointing vector (i.e., vector oriented along the core axis) and the core roll (i.e., the solid body angle of rotation around the pointing vector). We estimated the core pointing vector from the attitude of the rover's Coring Drill during drilling. To orient the core roll, we used oriented images of asymmetric markings on the bedrock surface acquired with the rover's Wide Angle Topographic Sensor for Operations and eNgineering (WATSON) camera. For most samples, these markings were in the form of natural features on the outcrop, while for four samples they were artificial ablation pits produced by the rover's SuperCam laser. These cores are the first geographically‐oriented (<2.7° 3σtotal uncertainty) bedrock samples from another planetary body. This will enable a diversity of paleomagnetic, sedimentological, igneous, tectonic, and astrobiological studies on the returned samples. 

Paleomagnetic, rock magnetic, or geomagnetic data found in the MagIC data repository from a paper titled: Testing the accuracy of absolute intensity estimates of the ancient geomagnetic field using copper slag material