Earth and Planetary Science Letters最新文献

{"title":"Structural characterization of archaeal GDGT cyclization: Linking physiological adaptation to paleotemperature reconstruction","authors":"Jiaming Zhou ,&nbsp;Liang Dong","doi":"10.1016/j.epsl.2025.119293","DOIUrl":"10.1016/j.epsl.2025.119293","url":null,"abstract":"<div><div>Glycerol dialkyl glycerol tetraethers (GDGTs), membrane lipids produced by archaea, have been widely utilized as biomarkers for paleotemperature reconstructions. While the relationship between GDGTs and temperature adaptation has been studied, the effects of structural modifications, specifically cyclopentane and cyclohexane rings, on membrane properties remains insufficiently understood. In this study, molecular dynamics simulations were employed to examine how these structural modifications influence GDGT membrance fluidity, with an emphasis on high-temperature adaptation in archaea. Our results demonstrate that an increasing number of cyclopentane rings is assoicated with reduced membrane fluidity, highlighting their role in facilitating high-temperature acclimation. Additionally, cyclohexane modifications in crenarchaeol, along with its isomerization, further reduce membrane fluidity. These findings indicate a clear link between lipid cyclization and thermal adaptation in archaea. Furthermore, the significant differences in membrane fluidity between GDGT-1 and GDGT-2 are consistent with the theoretical basis of the TEX₈₆ temperature proxy. Interestingly, while the cyclohexane modification of crenarchaeol in environmental samples suggests cold adaptation, this observation contrasts to findings from culture data and molecular dynamic simulations, suggesting the influence of additional factors. Based on these insights, we propose a novel sea surface temperatures reconstruction metric, TEX₈₆^MD, which enhances the accuracy of the TEX₈₆ proxy, and provides broader global applicability, especially in the polar regions.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"657 ","pages":"Article 119293"},"PeriodicalIF":4.8,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551706","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":"Stress-controlled reaction pattern in the layered lower crust: Field evidence","authors":"Marie Baïsset ,&nbsp;Loïc Labrousse ,&nbsp;Philippe Yamato ,&nbsp;Anaïs Cochet","doi":"10.1016/j.epsl.2025.119270","DOIUrl":"10.1016/j.epsl.2025.119270","url":null,"abstract":"<div><div>Stress can strongly modify the mechanical and transport properties of rocks. This effect is particularly important for metamorphic equilibria in subduction zones where metamorphic reactions and deformation are often concomitant. However, the impact of stress on the propagation of high pressure metamorphic reactions remains largely under-explored. The island of Holsnøy (Norway) shows incipient eclogitization affecting layered continental granulites along shear zones and puzzling finger-shaped structures. While eclogite shear zones suggest that reaction progress is controlled by strain, a mechanism is still required to explain the propagation of finger-shaped reaction fronts in adjacent low-strain domains. Here, we present a detailed structural analysis of the partially eclogitized Holsnøy massif that highlights the relationship between fingers and shear zones in the anisotropic granulite. We show that these structures are not randomly distributed. Finger-shaped eclogite fronts preferentially propagate along the granulite foliation when layering is at high angle to the local maximal principal stress <em>σ</em>₁. This feature can be described using the Damköhler number from the theory of reactive transport. Conjunction of anisotropic eclogitization kinetics and anisotropic stress state actually controls the possible development of finger-shaped reaction fronts.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"657 ","pages":"Article 119270"},"PeriodicalIF":4.8,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143534671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Grain-scale feedback between deformation mechanisms and metamorphic reactions: Dissolution-precipitation processes in the lower crust (Kågen gabbros)","authors":"Louise Mérit ,&nbsp;Mathieu Soret ,&nbsp;Benoît Dubacq ,&nbsp;Philippe Agard ,&nbsp;Jacques Précigout ,&nbsp;Holger Stünitz","doi":"10.1016/j.epsl.2025.119275","DOIUrl":"10.1016/j.epsl.2025.119275","url":null,"abstract":"<div><div>Strain localization within crustal shear zones involves intricate feedback between deformation mechanisms, metamorphic reactions and fluid circulation. Despite evidence that these high-deformation zones proceed at least partly through dissolution-precipitation creep, available creep laws so far only account for dislocation creep and/or solid-state diffusion processes. Deciphering the role and the contribution of dissolution-precipitation creep to strain accommodation is now required to further understand the rheological behavior of polymineralic crustal rocks. This study combines high-resolution microstructural and compositional analytical techniques to track the progressive deformation of the Kågen metagabbros, at and below grain scale. The Kågen metagabbros preserved a strain and re-equilibration gradient over outcrop-scale, where metamorphic re-equilibrations and fluid infiltration took place at constant pressure and temperature representative of lower crustal conditions (ca. 1 GPa - 660 ± 25 °C). The comparison and quantification of chemical and microstructural information in this shear zone, through pixel-per-pixel and grain-per-grain correlated EPMA and EBSD maps, enables tracking grain-scale deformation mechanisms as well as the interplay between grain size reduction, mineral reactions, phase mixing and material transfer. Dissolution-precipitation creep appears dominant for strain accommodation in the Kågen metagabbros shear zone. As deformation progresses, nucleation of new metamorphic minerals (clinopyroxene, plagioclase, amphibole) allow for grain size reduction and compositional homogenization through dissolution, transport and precipitation processes associated with fluid ingression along grain boundaries. Intracrystalline plastic deformation is here insignificant for strain accommodation. Thermodynamic modeling and textural analysis reveal that re-equilibration processes are spatially controlled by microdomains where equilibrium is reached locally, on a scale of ∼100 µm.</div><div>This study calls for integrating reactions, dissolution-precipitation processes, fluids and polymineralic assemblages into rheological laws for a reliable assessment of the mechanical evolution of metamorphic rocks.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"656 ","pages":"Article 119275"},"PeriodicalIF":4.8,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reactive dissolution of plagioclase in a basaltic melt: A chronometer for pre-eruptive volcanic processes","authors":"M. Masotta ,&nbsp;F. Colle ,&nbsp;S. Costa ,&nbsp;P. Landi","doi":"10.1016/j.epsl.2025.119249","DOIUrl":"10.1016/j.epsl.2025.119249","url":null,"abstract":"<div><div>Dissolution and reaction textures of plagioclase phenocrysts in basaltic rocks testify to perturbations of the magmatic system that are frequently associated with pre-eruptive mixing processes. Dissolution-reaction experiments performed at 150 MPa and 1150–1300 °C are used to examine and quantify the timescales of reactive dissolution of plagioclase in a basaltic melt. Simple dissolution occurs under high degrees of plagioclase undersaturation, whereas, at conditions near the plagioclase <em>liquidus</em>, reactive dissolution is expressed by a noticeable decrease in crystal size and the formation of An-rich reaction zones. The total amount of crystal dissolution (<em>d_dissolution</em>) and the width of the reaction zone (<em>d_reaction</em>) increase with time according to an exponential law, yet more rapidly than what predicted by assuming diffusion in plagioclase as the rate limiting factor. The remarkably fast dissolution rate (∼10^–8 m/s) is explained by the formation of planar dissolution interfaces that initially accelerate the dissolution process, whilst the increasing textural maturation of the reaction zone counteracts this effect. A chronometer for retrieving the timescales of reactive dissolution from the width of reaction bands and rims in plagioclase phenocrysts contained in basaltic rocks is derived from the experimental data. The application of this chronometer to Stromboli volcano (Italy), where reaction rims in plagioclase are attributed to the pre-eruptive mixing between a deeper volatile-rich magma (<em>lp</em>-magma) with a degassed magma residing at shallow depths (hp-magma), permits to determine a characteristic timescale of 161±43 min for mixing episodes preceding more energetic eruptions.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"656 ","pages":"Article 119249"},"PeriodicalIF":4.8,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520197","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":"Redox processes at the slab-mantle interface: Evidence from reduced carbon inclusions in mantle wedge peridotites","authors":"Yi Su 苏懿 ,&nbsp;Shuning Li 李姝宁 ,&nbsp;Ren-Xu Chen ,&nbsp;Yong-Fei Zheng","doi":"10.1016/j.epsl.2025.119272","DOIUrl":"10.1016/j.epsl.2025.119272","url":null,"abstract":"<div><div>Carbonate-bearing fluids derived from subducting slabs are important agents in crust-mantle interactions that can modify the composition and oxidation state of the overlying mantle wedge. Here we use magnesite-bearing metasomatic veins as well as fluid inclusions in the mantle wedge harzburgite to investigate multiple stages of fluid-mantle interactions which initialize the mantle oxidation and chemical transformation of carbon-bearing species. We find that compositional growth zones in metasomatic minerals record three stages of changes in <em>f</em>O₂, fluctuating from FMQ-1 to FMQ-5 and back to FMQ-1.5. Such <em>f</em>O₂ fluctuation corresponds to the presence of carbon-bearing species with varying valence states, including magnesite, amorphous carbon, graphite, nanosized diamond, as well as methane and organic compounds. We suggest that multiple stages of fluid-mantle interactions, regulated by oxidation states of the evolving carbonaceous fluid, provide a mechanism for the abiotic formation of organic carbon at the slab-mantle interface.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"656 ","pages":"Article 119272"},"PeriodicalIF":4.8,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511211","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":"From hydrated silica to quartz: Potential hydrothermal precipitates found in Jezero crater, Mars","authors":"P. Beck ,&nbsp;O. Beyssac ,&nbsp;E. Dehouck ,&nbsp;S. Bernard ,&nbsp;M. Pineau ,&nbsp;L. Mandon ,&nbsp;C. Royer ,&nbsp;E. Clavé ,&nbsp;S. Schröder ,&nbsp;O. Forni ,&nbsp;R. Francis ,&nbsp;N. Mangold ,&nbsp;C.C. Bedford ,&nbsp;A.P. Broz ,&nbsp;E.A. Cloutis ,&nbsp;J.R. Johnson ,&nbsp;F. Poulet ,&nbsp;T. Fouchet ,&nbsp;C. Quantin-Nataf ,&nbsp;C. Pilorget ,&nbsp;R.C. Wiens","doi":"10.1016/j.epsl.2025.119256","DOIUrl":"10.1016/j.epsl.2025.119256","url":null,"abstract":"<div><div>On Earth, silica-rich phases from opal to quartz are important indicators and tracers of geological processes. Hydrated silica, such as opal, is a particularly good matrix for the preservation of molecular and macroscopic biosignatures. Cherts, a type of silica-dominated rocks, provide a unique archive of ancient terrestrial life while quartz is the emblematic mineral of the Earth's continental crust. On Mars, hydrated silica has been detected in several locations based on remote sensing and rover-based studies. In the present article we report on the detection of cobbles made of hydrated silica (opal or chalcedony), as well as well-crystallized quartz. These detections were made with the SuperCam instrument onboard Perseverance (Mars 2020 mission), using a combination of LIBS, infrared and Raman spectroscopy. Quartz-dominated stones are detected unambiguously for the first time on the Martian surface, and based on grain size and crystallinity are proposed to be of hydrothermal origin. Although these rocks were all found as float, we propose that these detections are part of a common hydrothermal system, and represent different depths / temperatures of precipitation. This attests that hydrothermal processes were active in and around Jezero crater, possibly triggered by the Jezero crater-forming impact. These silica-rich rocks, in particular opaline silica, are very promising targets for sampling and return to Earth given their high biosignature preservation potential.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"656 ","pages":"Article 119256"},"PeriodicalIF":4.8,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143511210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A general machine learning model of aluminosilicate melt viscosity and its application to the surface properties of dry lava planets","authors":"Charles Le Losq ,&nbsp;Clément Ferraina ,&nbsp;Paolo A. Sossi ,&nbsp;Charles-Édouard Boukaré","doi":"10.1016/j.epsl.2025.119287","DOIUrl":"10.1016/j.epsl.2025.119287","url":null,"abstract":"<div><div>Ultra-short-period exoplanets like K2-141 b likely have magma oceans on their dayside, which play a critical role in redistributing heat within the planet. This could lead to a warm nightside surface, measurable by the James Webb Space Telescope, offering insights into the planet's structure. Accurate models of properties like viscosity, which can vary by orders of magnitude, are essential for such studies.</div><div>We present a new model for predicting molten magma viscosity, applicable in diverse scenarios, including magma oceans on lava planets. Using a database of 28,898 viscosity laboratory measurements on phospho-alumino-silicate melts, spanning superliquidus to undercooled temperatures and pressures up to 30 GPa, we trained a greybox artificial neural network, refined by a Gaussian process. This model achieves high predictive accuracy (RMSE <span><math><mo>≈</mo><mn>0.4</mn><msub><mrow><mi>log</mi></mrow><mrow><mn>10</mn></mrow></msub></math></span> Pa⋅s) and can handle compositions from SiO₂ to multicomponent magmatic and industrial glasses, accounting for pressure effects up to 30 GPa for compositions such as peridotite.</div><div>Applying this model, we calculated the viscosity of K2-141 b's magma ocean under different compositions. Phase diagram calculations suggest that the dayside is fully molten, with extreme temperatures primarily controlling viscosity. Even in the absence of major volatiles (H, C, N), a tenuous rock-vapour atmosphere (0.1 bar) might exist around a 40° radius from the substellar point. At higher longitudes, atmospheric pressure drops, and by 90°, magma viscosity rapidly increases as solidification occurs. The nightside surface is likely solid, but previously estimated surface temperatures above 400 K imply a partly molten mantle, supporting geothermal flux through vertical convection.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"656 ","pages":"Article 119287"},"PeriodicalIF":4.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143510643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Earth's earliest known extensive, thick carbonate platform suggested by new age constraints","authors":"Philip Fralick ,&nbsp;Donald W. Davis ,&nbsp;Munira Afroz ,&nbsp;Brittany Ramsay ,&nbsp;Laureline Patry ,&nbsp;Dylan Wilmeth ,&nbsp;Martin Homann ,&nbsp;Pierre Sansjofre ,&nbsp;Robert Riding ,&nbsp;Stefan V. Lalonde","doi":"10.1016/j.epsl.2025.119273","DOIUrl":"10.1016/j.epsl.2025.119273","url":null,"abstract":"<div><div>Proterozoic and Phanerozoic carbonate platforms have provided considerable information on how the flora, fauna and water chemistry of warm, shallow seas evolved through time. This contrasts with the relative scarcity of Archean examples of these extensive repositories of biochemical and chemical sediments. Until now the late Neoarchean Campbellrand-Malmani and Hamersley carbonate platforms have provided the only examples of extensive, thick Archean carbonate deposits. Scattered outcrop areas of Mesoarchean carbonate, up to 400 m thick, are present in western Superior Province, but past geochronology has assigned significantly different ages to them. A reappraisal of previously dated felsic volcanic rocks as sandstones, combined with new U-Pb zircon geochronology conducted on intermediate to felsic tuffs, determined that four of these carbonate occurrences, now scattered over 2300 km², were deposited between 2.87 Ga and 2.85 Ga. The realization that an extensive, thick carbonate platform, and deeper water chronostratigraphic equivalents (Slate Bay Assemblage), are probably present in this area provides a basis for future comprehensive studies of the relationships between the various types of depositional processes and compositions of seawater chemistry developed on and above the Mesoarchean seafloor.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"656 ","pages":"Article 119273"},"PeriodicalIF":4.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The partitioning of selenium and tellurium between sulfide liquid and silicate melt and their abundances in the silicate Earth","authors":"Zhiwei Liu ,&nbsp;Yuan Li","doi":"10.1016/j.epsl.2025.119277","DOIUrl":"10.1016/j.epsl.2025.119277","url":null,"abstract":"<div><div>Near-chondritic relative abundances of sulfur (S), selenium (Se), and tellurium (Te) observed in mantle peridotites have been used to support the hypothesis of a carbonaceous chondrite-like late veneer added to the proto-Earth. However, the extent to which the observed S, Se, and Te compositions represent the signature of the silicate Earth remains a topic of debate. The concentrations of Se and Te in mantle-derived melts, such as mid-ocean ridge basalts (MORBs), can help clarify this issue, provided we have a precise understanding of the behavior of Se and Te during magmatic differentiation and mantle partial melting. Here we conduct laboratory experiments to determine the sulfide liquid–silicate melt partition coefficients of Se and Te (<span><math><msubsup><mi>D</mi><mrow><mi>S</mi><mi>e</mi><mo>,</mo><mspace></mspace><mi>T</mi><mi>e</mi><mspace></mspace></mrow><mrow><mi>S</mi><mi>u</mi><mi>l</mi><mo>/</mo><mi>S</mi><mi>i</mi><mi>l</mi></mrow></msubsup></math></span>) at crust–mantle conditions. Our results indicate that <span><math><msubsup><mi>D</mi><mrow><mi>S</mi><mi>e</mi><mo>,</mo><mspace></mspace><mi>T</mi><mi>e</mi><mspace></mspace></mrow><mrow><mi>S</mi><mi>u</mi><mi>l</mi><mo>/</mo><mi>S</mi><mi>i</mi><mi>l</mi></mrow></msubsup></math></span> range from 180 to 2200 for Se and from 1000 to 25,400 for Te, exhibiting an inverted U-shaped dependence on the FeO_tot content in silicate melt. We parameterize <span><math><msubsup><mi>D</mi><mrow><mi>S</mi><mi>e</mi><mo>,</mo><mspace></mspace><mi>T</mi><mi>e</mi><mspace></mspace></mrow><mrow><mi>S</mi><mi>u</mi><mi>l</mi><mo>/</mo><mi>S</mi><mi>i</mi><mi>l</mi></mrow></msubsup></math></span> as a multi-function of the compositions of silicate melt and sulfide liquid, with pressure (0.5–2.5 GPa), temperature (1273–1973 K), and oxygen fugacity (FMQ-5 to FMQ+1.5; FMQ refers to the fayalite–magnetite–quartz buffer) having negligible effects on <span><math><msubsup><mi>D</mi><mrow><mi>S</mi><mi>e</mi><mo>,</mo><mspace></mspace><mi>T</mi><mi>e</mi><mspace></mspace></mrow><mrow><mi>S</mi><mi>u</mi><mi>l</mi><mo>/</mo><mi>S</mi><mi>i</mi><mi>l</mi></mrow></msubsup></math></span>. Applying our parameterization to magmatic differentiation can effectively account for the Se, Te, and Cu systematics observed in both MORBs and oxidized arc magmas. More significantly, when applied to mantle partial melting, alongside high-precision Se and Te concentration data from MORBs, our parameterization yields superchondritic S/Se, S/Te, and Se/Te ratios in the depleted MORB mantle and primitive mantle, compared to carbonaceous chondrites. These findings suggest that the S, Se, and Te abundances in the silicate Earth were likely established during the main accretion phase, with the late veneer playing only a minor role.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"656 ","pages":"Article 119277"},"PeriodicalIF":4.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes in thermoluminescence sensitivity of 110°C glow peak of quartz grains from sediments of River Ganga: Observation and implications","authors":"S. Parida,&nbsp;R.K. Kaushal,&nbsp;N. Chauhan,&nbsp;A.K. Singhvi","doi":"10.1016/j.epsl.2025.119267","DOIUrl":"10.1016/j.epsl.2025.119267","url":null,"abstract":"<div><div>The luminescence sensitivity of minerals is being increasingly used to extract information related to geological and geomorphic phenomena experienced by rocks and sediments. Luminescence sensitivity of quartz depends on the source rock, and subsequent changes in it by exposure to ionizing radiation, heating (e.g. forest fires) and daylight exposures during cycles of sedimentation, burial and remobilisation. In the case of sediments, the travel distance has often been implicated for changes in luminescence sensitivity (LS; TLS for thermoluminescence sensitivity and OSLS for optically stimulated luminescence sensitivity).</div><div>This study documents changes in TLS of quartz grains from active bar sediments from four transects totalling to ∼4000 km in the Ganga River system (the Ganga, Yamuna, Ramganga and Chambal rivers), and examines its possible use for sediment provenance and in the estimation of sediment fluxes at confluences. This study enables following observations:</div><div>1. In a given reach between two major tributary confluences, TLS in UV and blue emissions for both bleached and unbleached samples showed similar behaviour. However, OSLS showed large variability, due possibly to changes caused by bleaching (Singhvi et al., 2011). This suggest that the often used OSLS on bleached samples should be avoided for such provenance studies.</div><div>2. No clear dependence of TLS on transport distance was seen, due possibly to the fact that these rivers transport sediments under turbid flow conditions and therefore, most grains do not receive the requisite daylight exposure.</div><div>3. TLS of quartz grains from rocks, regolith and fluvial sediments from the Chambal and Ramganga basins suggest that duration of sediment generation processes is key to sensitisation of quartz TLS. This observation leads to a plausible suggestion that TLS can serve as a surrogate of denudation rates, currently being estimated using cosmogenic isotopes.</div><div>4. Large variations in TLS in the areas of sand mining, offer a potential to use it in estimating the volumes of sands extracted, a factor critical for sustainability of river systems and economics. This needs to be explored further.</div><div>5. Single-grain OSLS suggests that grains with signal-to-background ratio (S/B) 5–50 contribute significantly towards OSLS and changes in the population of grains with S/B 5–50 and &gt; 50 could also serve as tracer for sediment provenance.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"656 ","pages":"Article 119267"},"PeriodicalIF":4.8,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143480172","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}