Earth and Planetary Science Letters最新文献

{"title":"Was the mantle warmer when Pangea broke up? insights from initial oceanic crustal thickness alongside the rifted margins of the Atlantic and Indian Oceans","authors":"Daniel Sauter ,&nbsp;Gianreto Manatschal ,&nbsp;Nick Kusznir ,&nbsp;Nicolas Coltice ,&nbsp;Pauline Chenin ,&nbsp;Marc Ulrich ,&nbsp;Marie Garbaciak ,&nbsp;Philippe Werner","doi":"10.1016/j.epsl.2026.119897","DOIUrl":"10.1016/j.epsl.2026.119897","url":null,"abstract":"<div><div>Insulation by the Pangean supercontinent has been suggested to have resulted in subcontinental mantle thermal anomalies and enhanced magmatic activity that may have influenced continental breakup. However, the thermal state of the mantle during the rifting of Pangea is not well established by geophysical and geochemical data. We present a compilation of oceanic crustal thicknesses next to the rifted margins of the Atlantic and Indian Oceans to investigate the variations of magma budget along the initial spreading centers, and thus the thermal state of the mantle immediately after breakup. We show that the initial oceanic crustal thickness values show a bimodal distribution with two modes centered around ∼5.5 km and ∼6.7 km. The first mode (∼5.5 km) corresponds mostly to initial oceanic crusts from the Equatorial Atlantic and is thinner than present-day normal oceanic crust (∼6.1 km thick). It could result from a cold thermal anomaly related to thick pre-opening equatorial continental lithosphere. The thicker than normal oceanic crusts of the second mode (∼6.7 km) could result from a small positive mantle potential temperature anomaly of 9–15 °C. In the Central Atlantic, which opened in Jurassic time after the Central Atlantic Magmatic Province event, this thermal anomaly could reach ∼60 °C at most to produce ∼9 km thick initial oceanic crust. We thus propose that the insulation effect of Pangea might have controlled locally the thermal state of the asthenosphere but it cannot be considered as a generally ubiquitous effect associated with the breakup of Pangea.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"680 ","pages":"Article 119897"},"PeriodicalIF":4.8,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147109","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sediment-derived deep forearc fluid caused coupled sulfur-Fe3+-enrichment in eclogite from the subducted Farallon plate","authors":"Sonja Aulbach ,&nbsp;Johannes E. Pohlner ,&nbsp;Richard A. Stern ,&nbsp;Heidi E. Höfer ,&nbsp;Daniel J. Schulze ,&nbsp;Herwart Helmstaedt","doi":"10.1016/j.epsl.2026.119883","DOIUrl":"10.1016/j.epsl.2026.119883","url":null,"abstract":"<div><div>Sulfur is a key element in geochemical cycles and ore formation, but where, how and in which speciation it is mobilised in subduction zones remains unclear. Here, we investigate the petrography, geochemistry and Sr-Nd-S-O isotopic composition of pyrite-bearing eclogite and omphacitite xenoliths from the Navajo Volcanic Field, which likely sample the oceanic crust of the Cretaceous Farallon Plate at sub-arc depths inaccessible to tectonically exhumed eclogites. After eclogitisation (∼2.4–3.3 GPa, 400-&lt;550 °C), the Farallon oceanic crust experienced two well-documented enrichment events: (1) Ingress of siliceous sediment-derived fluid converting eclogite to omphacitite under deep forearc conditions (∼3–3.5 GPa, &gt;500-&lt;600 °C) and (2) interaction with serpentinite-derived fluid with discrete formation of high-MgO garnet rims under sub-arc conditions (&gt;3.5 GPa, &gt;550 °C). This provides the exceptional opportunity to study the behaviour of sulfur during multi-stage metasomatism in deep subduction zones. High-MgO garnet rims, with mantle-like δ¹⁸O values (down to +5.62‰) that contrast with higher δ¹⁸O values in the garnet cores (up to +9.63‰), have distinctly lower Fe³⁺/ΣFe than the cores and are devoid of sulphide inclusions, documenting reduction – rather than oxidation – by serpentinite-derived fluid. Omphacitites have crustal Sr-Nd isotopic compositions, and pyrite is significantly co-enriched with omphacite, both showing marked oscillatory zoning. Supra-mid-ocean ridge basalt sulfur isotopic compositions in four pyrite grains (δ³⁴S_V-CDT = +0.62±0.05 to +9.03±0.09‰) and highly variable δ³⁴S_V-CDT (-5.60 to +5.86‰) in another grain indicate some incorporation of sulphate-derived sulfur in omphacitites, which also have higher bulk Fe³⁺/ΣFe than their precursor eclogites. In the absence of carbon-bearing minerals, the distinct enrichment of fluid-immobile Fe³⁺ in omphacitites combined with isotopically heavy S in pyrite are ascribed to iron-sulfur redox interactions via ingress of metasediment-derived fluid. The average fraction oxidised S needed to explain the Fe³⁺ enrichment in the omphacitites is lower than the total S that was added (corresponding to S⁶⁺/Σ<em>S</em> = 0.30±0.27, <em>n</em> = 15), adding to increasing evidence for substantial mobility of both reduced and oxidised S within subducted oceanic crust. The subduction-modified Farallon oceanic crust may become an oxygen source upon recycling into more reduced mantle regions and impart an ⁸⁷Sr-³⁴S-enriched signature without the direct involvement of metasedimentary components.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"680 ","pages":"Article 119883"},"PeriodicalIF":4.8,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146187282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coupled thermochemical evolution of the early Earth’s solid mantle and basal magma ocean: The role of melting and melt transport","authors":"Laura H. Lark ,&nbsp;Charles-Édouard Boukaré ,&nbsp;James Badro ,&nbsp;Henri Samuel","doi":"10.1016/j.epsl.2026.119880","DOIUrl":"10.1016/j.epsl.2026.119880","url":null,"abstract":"<div><div>Differentiation of Earth’s magma ocean likely created chemical heterogeneity, leading to a gradually stratified deep mantle overlying a basal magma ocean (BMO). The Earth’s thermochemical evolution hinges on the fate of this early stratification. At this stage, the solid mantle is near-solidus, so deep convective motions are probably strongly influenced by solid-liquid phase change. However, the preservation or modification of stratification is poorly understood in the presence of partial melting. We investigate the evolution of a compositionally stratified deep mantle considering melt-related processes and interaction between the solid mantle and BMO. We determine that bottom-heating of the stratified solid mantle by a radioactively heated BMO or a cooling core powers restructuring of stratification in two regimes: (1) if produced melt can drain effectively, downward percolation of fractional melt removes the enriched, dense, stratifying component to the growing BMO; (2) otherwise, hot or melt-rich plumes stir the initially stratified material, which retains its original composition. We present a numerically-validated analytical model which predicts both the timescale and the different regimes of stratification restructuring. Applying this model to Earth, we determine that gradual stratification in the deep solid mantle would have been restructured by the early Archean by drainage of low-degree partial melts. This process would leave the early Earth with a depleted deep mantle only slightly denser than the shallow mantle, and a voluminous BMO. The deep solid reservoirs may be relatively easily entrained into the convecting shallow mantle, whereas the BMO could act as a more persistent source of heterogeneity.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"680 ","pages":"Article 119880"},"PeriodicalIF":4.8,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A laboratory model for Jovian polar vortex crystals","authors":"Djihane Benzeggouta,&nbsp;Benjamin Favier,&nbsp;Michael Le Bars","doi":"10.1016/j.epsl.2026.119877","DOIUrl":"10.1016/j.epsl.2026.119877","url":null,"abstract":"<div><div>We present an experimental model in which three similar cyclonic vortices are released into the upper layer of a rotating, two-layer stratified fluid system with a free upper surface, and spontaneously organize into a stable, long-lived vortex crystal. We analyze the crystal organization using a simplified toy model, in which the radial dynamics arise from a balance between an attractive force (the <em>β</em>-effect) and repulsive interactions between neighboring vortices. The experimental equilibrium distance agrees with the toy-model predictions. It increases with lower cyclone shielding, a greater number of vortices, and the presence of a central vortex. The azimuthal drift of the vortex crystals strongly correlates with their radial spacing: when far apart, they drift westward due to the <em>β</em>-drift, as seen at Jupiter’s poles; when close, strong mutual advection leads to eastward drift.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"680 ","pages":"Article 119877"},"PeriodicalIF":4.8,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hydrogen diffusivity in iron-bearing olivine at asthenospheric mantle conditions","authors":"Sylvie Demouchy ,&nbsp;Catherine Thoraval ,&nbsp;Emmanuel Gardés ,&nbsp;Nathalie Bolfan-Casanova ,&nbsp;Tiziana Boffa-Ballaran ,&nbsp;Geeth Manthilake","doi":"10.1016/j.epsl.2026.119899","DOIUrl":"10.1016/j.epsl.2026.119899","url":null,"abstract":"<div><div>The effect of pressure on hydrogen diffusivity in San Carlos olivine (Fo₉₀) single crystals was determined from hydrogenation experiments in a multi-anvil press at 6, 9 and 12 GPa, and at high temperature (900-1300°C), for various durations. Crystallographically oriented prisms of gem-quality San Carlos olivine were hydrogenated under controlled oxygen fugacity (Ni-NiO) and silica activity (10% Opx). Polarized Fourier-transform infrared spectroscopy was used to quantify the hydroxyl distribution in the samples parallel to the crystallographic axes. The diffusivity of hydrogen is consistent with a single diffusion mechanism, proton-vacancy coupled diffusion, which is dominated by the presence of trivalent ions (infrared band doublet at 3357-3329 cm⁻¹). The inferred chemical diffusion coefficients are slower than in olivine hydrogenated at lower pressure (≤ 3 GPa) for the same diffusion mechanism and temperatures. Under the given experimental conditions, diffusion along the [001] axis is slightly faster than along [100] or [010]. A global fit to the data provides a master Arrhenius law of the metal vacancy diffusion (which rate-limits the hydrogen diffusion) along [001]: <span><math><mrow><msubsup><mi>D</mi><mrow><msub><mi>V</mi><mrow><mi>M</mi><mi>e</mi></mrow></msub></mrow><mrow><mo>[</mo><mn>001</mn><mo>]</mo></mrow></msubsup><mo>=</mo><msubsup><mi>D</mi><mrow><mn>0</mn><mo>,</mo><msub><mi>V</mi><mrow><mi>M</mi><mi>e</mi></mrow></msub></mrow><mrow><mo>[</mo><mn>001</mn><mo>]</mo></mrow></msubsup><mi>e</mi><mi>x</mi><mi>p</mi><mrow><mo>[</mo><mrow><mo>−</mo><mo>(</mo><mrow><mi>Q</mi><mo>+</mo><mi>P</mi><mi>V</mi></mrow><mo>)</mo><mo>/</mo><mi>R</mi><mi>T</mi></mrow><mo>]</mo></mrow></mrow></math></span>, with the pre-exponential factor<span><math><mrow><msubsup><mi>D</mi><mrow><mn>0</mn><mo>,</mo><msub><mi>V</mi><mi>Me</mi></msub></mrow><mrow><mo>[</mo><mn>001</mn><mo>]</mo></mrow></msubsup><mo>=</mo><msup><mrow><mn>10</mn></mrow><mrow><mo>−</mo><mn>4.00</mn><mo>(</mo><mo>±</mo><mn>0.46</mn><mo>)</mo></mrow></msup><msup><mrow><mrow><mi>m</mi></mrow></mrow><mn>2</mn></msup><msup><mrow><mrow><mi>s</mi></mrow></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math></span>, the activation energy Q=183,000(±12,000) J.mol⁻¹, and the activation volume V=3.38(±0.37)×10⁻⁶ m³.mol⁻¹, and where pressure (P) is in Pa and the temperature (T) is in K. Despite the pressure effect, hydrogen diffusion coefficients in the entire upper mantle remain fast enough to alter hydrogen concentrations at the grain scale, although too slow to enable km-scale re-equilibration of hydrogen-rich or hydrogen-poor anomalies. Melt migration is thus required to enable large-scale re-equilibration of H heterogeneities.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"680 ","pages":"Article 119899"},"PeriodicalIF":4.8,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146187281","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cratonic impact on clastic-dominated base metal deposits in continental rifts","authors":"Anne C. Glerum ,&nbsp;S. Brune ,&nbsp;J. M. Magnall ,&nbsp;P. Weis ,&nbsp;S. A. Gleeson","doi":"10.1016/j.epsl.2026.119881","DOIUrl":"10.1016/j.epsl.2026.119881","url":null,"abstract":"<div><div>Sediment-hosted zinc-lead deposits of the clastic-dominated (CD) type provide much needed metals for the energy transition and global urbanization. There is a spatial correlation between the present-day location of CD-type deposits and craton edges, although it is unclear whether this is a causal relationship. In this paper, we use numerical models of continental rifting to investigate whether proximity to cratonic lithosphere enhances the ore-forming potential during rift basin evolution. Our results show that narrow asymmetric and wide rifts respond differently to the presence of close cratonic edges. The potential for metallogenesis in narrow asymmetric rifts decreases with increasing proximity to the craton edge. In contrast, metal source rock area and ore-forming mechanisms increase when wide rifts form close to a craton edge. We attribute these responses to the increased lithospheric strength on the craton-ward side of the rift that determines not only the initial fault geometry, but also the subsequent fault development and migration direction. This modifies the spatial and temporal overlap of the components of the mineral system required for deposit formation, i.e., source rock, fluid-focussing faults, and deposit host rock. The greatest metallogenic potential is found in the narrow margin of narrow asymmetric rifts formed far from a craton edge; here, the largest area of source rock is concentrated in the main border basin. The link between craton edges and metallogenic potential, therefore, is hypothesized to be due to the preferred initialization of rifts next to, and the preferential preservation of deposits on, the edges of stable cratons.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"680 ","pages":"Article 119881"},"PeriodicalIF":4.8,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Accumulation of volatiles under salt crusts in the highly evaporative Qaidam basin: Implications for salt crust fluid processes on Mars","authors":"Jiaming Zhu ,&nbsp;Bo Wu ,&nbsp;Zikang Li ,&nbsp;Yiliang Li","doi":"10.1016/j.epsl.2026.119904","DOIUrl":"10.1016/j.epsl.2026.119904","url":null,"abstract":"<div><div>The behavior of volatiles is critically important for understanding crustal fluids and the potential existence of a subsurface biosphere on Mars. However, our knowledge of the volatile cycle on Mars is limited by insufficient data from landed rovers and orbiter sensors. Halite salt crusts are widespread in the Qaidam Basin on the northern Tibetan Plateau due to strong evaporation under hyperarid climate conditions. We observed that the halite-dominated salt crust in the desiccated playa area diverts fluids percolating from depth to the surface, leading to the formation of raised polygonal rims enriched in gypsum. We drilled through the salt crust using a hand mill and measured the instantaneous gas concentrations and compositions. Beneath the halite salt crust, significantly higher concentrations of H₂O, CO₂, and CH₄ were detected compared with levels in the atmospheric background and at the polygonal rims. The thickness of the salt crust ranges from approximately 0.3 to 1 m, with halite content primarily between 5 and 30 wt%, and is comparable in scale to the thickness (typically &lt;3 m) and abundance (10–25 wt%) of chloride deposits on Mars. These results suggest that similar salt crust formation should also be common in Martian crater basins subjected to long-term evaporation under hyperarid conditions. Furthermore, such salt crusts could trap deep volatiles, including potential biogenic gases, which may be detectable by gas spectrometers aboard Mars landers.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"680 ","pages":"Article 119904"},"PeriodicalIF":4.8,"publicationDate":"2026-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146147112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Continued continental weathering during snowball earth mitigated greenhouse gas buildup and prolonged global glaciation","authors":"Shintaro Kadoya ,&nbsp;Mohit Melwani Daswani","doi":"10.1016/j.epsl.2026.119837","DOIUrl":"10.1016/j.epsl.2026.119837","url":null,"abstract":"<div><div>Global glaciations, also known as snowball events, represent some of Earth’s most significant climate changes. The Neoproterozoic Sturtian glaciation lasted 4–15 times longer than the subsequent Marinoan glaciation, but the causes of this dramatic difference remain unclear. The standard theory attributes the termination of such events to a pause in silicate weathering due to the absence of liquid water on continents. However, recent evidence of syn-glacial dolomite precipitation suggests the possibility of continental weathering during global glaciation. We numerically investigate water-rock reactions under limited water and fresh rock supplies to identify the key factors controlling subglacial weathering and to evaluate their impact on the carbon cycle during global glaciation. The compositions of the discharge fluid and mineral assemblage reach their steady state over a timescale determined by the rate of fresh rock supply. These steady-state compositions are identical when the ratio of the meltwater production rate (<span><math><msub><mi>F</mi><mtext>w</mtext></msub></math></span>) to the fresh rock supply rate (<span><math><msub><mi>F</mi><mtext>r</mtext></msub></math></span>) is constant (<span><math><mrow><msub><mi>F</mi><mtext>w</mtext></msub><mo>/</mo><msub><mi>F</mi><mtext>r</mtext></msub><mo>=</mo><mi>k</mi></mrow></math></span>). Furthermore, the maximum estimated CO₂ consumption could match Earth’s volcanic CO₂ emission, assuming present-day Antarctic conditions for meltwater production and fresh rock supply. This finding contradicts the standard assumption that silicate weathering ceases during global glaciation and suggests a mechanism for the prolonged duration of the Sturtian glaciation. These results demonstrate that subglacial weathering represents a previously unrecognized feedback mechanism that could account for the dramatically different durations of Neoproterozoic snowball Earth events.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"679 ","pages":"Article 119837"},"PeriodicalIF":4.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental determination of equilibrium fractionation of triple oxygen isotopes between dissolved sulfite species and water","authors":"Yu Wei ,&nbsp;Hao Yan ,&nbsp;Yan Fang","doi":"10.1016/j.epsl.2026.119862","DOIUrl":"10.1016/j.epsl.2026.119862","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Sulfite, a key intermediate sulfoxyanion in both the reductive and oxidative sulfur cycles, rapidly exchanges oxygen isotopes with ambient water under circumneutral to acidic conditions. Equilibrium oxygen isotope fractionation factors (&lt;sup&gt;18&lt;/sup&gt;&lt;em&gt;α&lt;/em&gt; and &lt;sup&gt;17&lt;/sup&gt;&lt;em&gt;α&lt;/em&gt;) between sulfite and water are therefore critical for interpreting the triple oxygen isotope composition of sulfate and for constraining sulfur cycling. However, equilibrium &lt;sup&gt;18&lt;/sup&gt;&lt;em&gt;α&lt;/em&gt; values remain poorly constrained, with significant discrepancies among experimental and theoretical estimates, largely due to experimental challenges in determining sulfite oxygen isotope compositions and uncertainties in theoretical calibrations. Moreover, equilibrium &lt;sup&gt;17&lt;/sup&gt;&lt;em&gt;α&lt;/em&gt; values have previously been derived only through theoretical calculation. In this study, we applied a pH-shifting technique to eliminate kinetic isotope effects during sulfite precipitation. We also employed a recently developed high-temperature reduction–discharge–CO&lt;sub&gt;2&lt;/sub&gt;/O&lt;sub&gt;2&lt;/sub&gt; isotope exchange technique to minimize the influence of sulfite hygroscopicity and precisely measured the triple oxygen isotope composition of sulfite equilibrated with water across a pH range of 4.60 to 8.89 and temperature range of 12 to 55 °C. Our results show a consistent, monotonic dependence of oxygen isotope fractionation between bulk sulfite (encompassing all S(IV)-oxyanions, including SO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;2–&lt;/sup&gt; and the bisulfite isomers (HS)O&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;–&lt;/sup&gt; and SO&lt;sub&gt;2&lt;/sub&gt;(OH)&lt;sup&gt;–&lt;/sup&gt;) and water on both pH and temperature. We attribute the former to pH-controlled speciation of dissolved sulfite. From our data, we derived equilibrium fractionation factors for oxygen isotopes between bisulfite and water, and between sulfite (SO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;2–&lt;/sup&gt;) and water:&lt;/div&gt;&lt;div&gt;1000ln&lt;sup&gt;18&lt;/sup&gt;&lt;em&gt;α&lt;/em&gt;&lt;sub&gt;bisulfite–H2O&lt;/sub&gt; = (7.06 ± 1.06) × 10&lt;sup&gt;3&lt;/sup&gt;/T – 8.80 ± 3.49&lt;/div&gt;&lt;div&gt;1000ln&lt;sup&gt;18&lt;/sup&gt;&lt;em&gt;α&lt;/em&gt;&lt;sub&gt;sulfite–H2O&lt;/sub&gt; = (6.59 ± 1.32) × 10&lt;sup&gt;3&lt;/sup&gt;/T – 12.56 ± 4.34&lt;/div&gt;&lt;div&gt;The associated mass-dependent fractionation exponents (&lt;em&gt;θ&lt;/em&gt; = ln&lt;sup&gt;17&lt;/sup&gt;&lt;em&gt;α&lt;/em&gt;/ln&lt;sup&gt;18&lt;/sup&gt;&lt;em&gt;α&lt;/em&gt;) are temperature-independent within our studied range, with values of 0.5202 ± 0.0003 for bisulfite and 0.5155 ± 0.0008 for sulfite. These imply that the Δ′&lt;sup&gt;17&lt;/sup&gt;O values of bisulfite and sulfite are offset by -0.152‰ and −0.143‰, respectively, from that of ambient water (assuming a reference slope of 0.5305) at 25 °C. Our findings offer new insights into the isotope fractionations associated with microbial sulfate reduction and pyrite oxidation. The observed pH-dependent variations in sulfate δ&lt;sup&gt;18&lt;/sup&gt;O signatures during abiotic aerobic pyrite weathering may reflect oxidation of distinct sulfite species under variable pH conditions. Furthermore, the isotope fractionation observed between residual sulfate and water during microbial sulfat","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"679 ","pages":"Article 119862"},"PeriodicalIF":4.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comment on: Evolution of iron formation to ore during Ediacaran to early Paleozoic tectonic stability, by Fuentes et al. (2025)","authors":"B. Rasmussen ,&nbsp;J-W. Zi ,&nbsp;J.R. Muhling ,&nbsp;I.R. Fletcher","doi":"10.1016/j.epsl.2026.119864","DOIUrl":"10.1016/j.epsl.2026.119864","url":null,"abstract":"","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"679 ","pages":"Article 119864"},"PeriodicalIF":4.8,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146036667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}