Earth and Planetary Science Letters最新文献

{"title":"Tungsten isotope evolution during Earth's formation and new constraints on the viability of accretion simulations","authors":"D.C. Rubie ,&nbsp;K.I. Dale ,&nbsp;G. Nathan ,&nbsp;M. Nakajima ,&nbsp;E.S. Jennings ,&nbsp;G.J. Golabek ,&nbsp;S.A. Jacobson ,&nbsp;A. Morbidelli","doi":"10.1016/j.epsl.2024.119139","DOIUrl":"10.1016/j.epsl.2024.119139","url":null,"abstract":"<div><div>The Hf-W isotopic system is the reference chronometer for determining the chronology of Earth's accretion and differentiation. However, its results depend strongly on uncertain parameters, including the extent of metal-silicate equilibration and the siderophility of tungsten. Here we show that a multistage core-formation model based on N-body accretion simulations, element mass balance and metal-silicate partitioning, largely eliminates these uncertainties. We modified the original model of Rubie et al. (2015) by including (1) smoothed particle hydrodynamics estimates of the depth of melting caused by giant impacts and (2) the isotopic evolution of ¹⁸²W. We applied two metal-silicate fractionation mechanisms: one when the metal delivered by the cores of large impactors equilibrates with only a small fraction of the impact-induced magma pond and the other when metal delivered by small impactors emulsifies in global magma oceans before undergoing progressive segregation. The latter is crucial for fitting the W abundance and ¹⁸²W anomaly of Earth's mantle. In addition, we show, for the first time, that the duration of magma ocean solidification has a major effect on Earth's tungsten isotope anomaly. We re-evaluate the six Grand Tack N-body simulations of Rubie et al. (2015). Only one reproduces ε¹⁸²W=1.9 ± 0.1 of Earth's mantle, otherwise accretion is either too fast or too slow. Depending on the characteristics of the giant impacts, results predict that the Moon formed either 143–183 Myr or 53–62 Myr after the start of the solar system. Thus, independent evaluations of the Moon's age provide an additional constraint on the validity of accretion simulations.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"651 ","pages":"Article 119139"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158123","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":"Thermal runaway and frictional melting in MORB-composition garnetite at high pressure: Implications for remote triggering of earthquakes in the transition zone","authors":"Fang Xu ,&nbsp;David P Dobson ,&nbsp;Katharina T Marquardt","doi":"10.1016/j.epsl.2025.119243","DOIUrl":"10.1016/j.epsl.2025.119243","url":null,"abstract":"<div><div>The origin of deep earthquakes remains enigmatic, but some seismic studies imply that in the deep transition zone transformation faulting cannot be the only (or even the major) mechanism. Here we present samples of co-existing basaltic-composition garnetite and San-Carlos-composition wadsleyite which were simultaneously deformed, resulting in a shear failure. Runaway frictional heating along the shear plane resulted in melting within the garnetite sample but not the wadsleyite sample. This fundamental difference in rupture evolution is also seen in the failure angles in the two samples, with the failure angle in the garnetite sample consistent with a low coefficient of friction, unlike the wadsleyite-hosted fault. Numerical shear-heating models confirm that the difference in behaviour is caused by the difference in thermal diffusivity of garnet and wadsleyite. We suggest therefore that thermal runaway is a viable mechanism for producing seismicity in crustal portions of subducted slabs in the deep transition zone.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"654 ","pages":"Article 119243"},"PeriodicalIF":4.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143300333","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":"Earthquake-triggered submarine canyon flushing transfers young terrestrial and marine organic carbon into the deep sea","authors":"Katherine L Maier ,&nbsp;Catherine E Ginnane ,&nbsp;Sebastian Naeher ,&nbsp;Jocelyn C Turnbull ,&nbsp;Scott D Nodder ,&nbsp;Jamie Howarth ,&nbsp;Sarah J Bury ,&nbsp;Robert G Hilton ,&nbsp;Jess IT Hillman","doi":"10.1016/j.epsl.2025.119241","DOIUrl":"10.1016/j.epsl.2025.119241","url":null,"abstract":"<div><div>Submarine canyons transfer substantial amounts of sediment and organic carbon (OC) into the deep ocean, nourishing deep-sea ecosystems and contributing to the global carbon cycle through OC burial and sequestration. Tracking lateral OC transport through submarine canyon systems is challenged by the deep-ocean setting, difficulties with constraining episodic depositional events, and the need to assess the composition and age of marine and terrestrial organic matter. We apply innovative parallel ramped pyrolysis oxidation-accelerator mass spectrometry and pyrolysis-gas chromatography-mass spectrometry with isotope analyses to track OC age and sources in the 2016 Kaikōura earthquake-triggered, canyon-flushing event that deposited along &gt;1300 km of a submarine canyon-channel system, offshore Aotearoa New Zealand. Specifically, these techniques allow us to determine the ages, sources, and partitioning of OC within the Kaikōura turbidite deposit and test hypotheses of how submarine canyon systems contribute to lateral OC flux and burial. Our results show that, despite considerable canyon floor erosion, substantial amounts of young OC were flushed into the deep sea, with relatively little (∼2 %) pre-Holocene OC contributions. Even without a direct connection between rivers and submarine canyons, most (∼55 %) of the OC in the Kaikōura event bed is from terrestrial sources. However, the deposit also contains substantial amounts (∼22 %) of marine-derived OC and ∼23 % of the material is of unassignable origin. Particle sorting imparts variability on the age and composition of OC within turbidite deposits and along the turbidity current flow path. Terrestrial-derived OC is preferentially older than marine-derived OC and concentrated in coarser particle sizes found more commonly at the deposit base and in proximal settings. Young, marine-derived OC is concentrated at the surface of the deposits and tends to be enriched in finer particle sizes. Such OC partitioning in turbidites supports the relevance of depositional models for predicting and quantifying distribution of OC in deep-sea deposits. Earthquake-triggered, canyon flushing events and resulting turbidites enhance OC burial efficiency and can sequester OC effectively, contributing an important carbon sink to the sedimentary carbon cycle.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"654 ","pages":"Article 119241"},"PeriodicalIF":4.8,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143300336","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":"Orogenic lamproites from Italy formed by mixing of highly potassic and shoshonitic melts","authors":"Antoine J.J. Bracco Gartner ,&nbsp;Igor K. Nikogosian ,&nbsp;Jan M. Aartsen ,&nbsp;Emrys L. Karlas ,&nbsp;Gareth R. Davies ,&nbsp;Janne M. Koornneef","doi":"10.1016/j.epsl.2025.119228","DOIUrl":"10.1016/j.epsl.2025.119228","url":null,"abstract":"<div><div>Strongly alkaline potassic magmas, such as lamproites and kimberlites, are prime examples of melts that require metasomatised mantle sources containing hydrous minerals, but the exact source assemblage and melt generation process is not well-understood. Here we investigate the source of orogenic lamproites and cogenetic shoshonites from the Plio-Pleistocene Tuscan magmatic province in central Italy, using the major-, volatile-, trace-element and Sr-Nd isotope compositions of melt inclusions (MIs) in Fo₈₄₋₉₅ olivine from Torre Alfina and Radicofani. The MIs hosted by exceptionally forsteritic olivine (Fo₉₃₋₉₅) have high K₂O (11–17 wt%), MgO (6–13 wt%) and low Al₂O₃ (7–13 wt%) and SiO₂ contents (47–56 wt%), clearly unlike the erupted lamproitic lavas. Their olivine hosts also contain carbon dioxide- and rare nitrogen-rich fluid inclusions. A second melt inclusion group, which occurs in Fo₈₈₋₉₃ olivine, records compositions that trend towards much lower K, Mg, and higher Al and Si contents. Both inclusion groups show positive correlations between P, F, Ca, Ti, and most trace elements, signifying an important and variable role for accessory apatite and Ti-oxide in the source. The compositions of the Fo₉₃₋₉₅ olivines and their exceptionally K-rich MIs closely resemble incongruent melting products of hydrous pyroxenites containing phlogopite, K-richterite, and clinopyroxene at ∼ 1.5–2 GPa. Coupled with the presence of nitrogen-rich inclusions, this suggests that these olivines and MIs are the products of the reaction K-richterite + phlogopite + clinopyroxene → melt + olivine, in which peritectic olivine trapped the melt with which it formed, and the nitrogen was liberated from ammonium-bearing phlogopite/amphibole. The second melt group records compositions that trend towards shoshonitic compositions created by melting of a phlogopite-bearing lherzolite. This shoshonitic melt is similar to Radicofani shoshonite MIs (in Fo₈₄₋₉₀ olivine), although the former requires some apatite and Ti-oxide in its source. In conclusion, the Tuscan lamproites are formed by mixing between unusually K-rich melts (∼ 20%) and shoshonitic melts (∼ 80%). These findings highlight the importance of incongruent melting and melt mixing in the generation of orogenic lamproites.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"654 ","pages":"Article 119228"},"PeriodicalIF":4.8,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143300334","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":"Decreased marine organic carbon burial during the Hirnantian glaciation","authors":"Shengchao Yang ,&nbsp;Junxuan Fan","doi":"10.1016/j.epsl.2025.119240","DOIUrl":"10.1016/j.epsl.2025.119240","url":null,"abstract":"<div><div>A significant glaciation occurred during the Late Ordovician Hirnantian Age, coinciding with the substantial positive Hirnantian Isotope Carbon Excursion (HICE, up to +7 ‰). Modeling studies suggest that both events were driven by increased organic carbon burial; however, this hypothesis has not been substantiated with global sedimentary organic carbon data, hampering our understanding of the underlying causes of the Hirnantian glaciation and the HICE. In this study, we compiled data from 25 globally distributed sections along continental shelves, each stratigraphically constrained by graptolite biozonation, to elucidate the evolution of global organic carbon burial and the marine carbon cycle during the Late Ordovician to Early Silurian (<em>Dicellograptus complexus</em> to <em>Akidograptus ascensus</em> biozones, 449.13 to 443.07 Ma). Our results indicate a rapid decline in organic carbon burial from the late Katian to the early Hirnantian, coinciding with the onset of glaciation and the rising limb of the HICE, which is in contrast to the increased organic carbon burial indicated by modeling. This discrepancy between the geological record and modeling results suggests that variations in organic carbon burial may not be the primary driver of the Hirnantian glaciation and the HICE, and necessitates a reassessment of the global carbon cycling during the Late Ordovician. The diminished organic carbon burial during the glaciation is likely associated with redox-dependent remineralization of organic matter and increased organic matter degradation timescales, indicating that the organic carbon cycle functioned as a negative feedback mechanism to global cooling during the Late Ordovician.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"654 ","pages":"Article 119240"},"PeriodicalIF":4.8,"publicationDate":"2025-01-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143300338","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":"Crustal deformation across the southeastern flank of the eastern Himalayan syntaxis from 3D velocity and anisotropic structures","authors":"Huigui Sun ,&nbsp;Lijun Chang ,&nbsp;Xiaodong Song ,&nbsp;Xingchen Wang","doi":"10.1016/j.epsl.2025.119230","DOIUrl":"10.1016/j.epsl.2025.119230","url":null,"abstract":"<div><div>The southeastern flank of the Eastern Himalayan Syntaxis (EHS) hosts both Tibetan Plateau extrusion and Indian Plate subduction and is a key location for understanding the tectonic transition from continental collision to plateau uplift and lateral extrusion. In this study, we used the densest broadband seismic arrays ever to extract dispersion curves for group and phase velocities with periods ranging from 3 to 40 s. The high-resolution 3-D radially and azimuthally anisotropic model obtained from ambient noise tomography provides valuable insights into interpreting crustal deformation. Our results reveal the differences in deformation mechanisms between tectonic plates on both sides of the Jinshajiang Fault-Red River Fault (JSJF-RRF) system. The Sichuan-Yunnan block on the eastern side exhibits positive radial anisotropy in the low-velocity weak layers of the mid-lower crust. Large-scale continuous crustal flow does not exist under the blocking of multiple fractures and high-velocity bodies, but rather localized material flow occurs due to partial melting. On the western side, the Indo-China Block (ICB) and the Yunnan-Myanmar-Thailand Block (YMTB) are distributed in complex depth‐variant anisotropy patterns. We consider this to be the combined result of clockwise rotation and extension, followed by asthenospheric upwelling and lateral crustal shortening during oblique eastward subduction of the Indian lithosphere, which further heated the lower crust. Additionally, the extension and deformation of mid-crustal melt on southeastern EHS significantly influence earthquake preparation and occurrence.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"654 ","pages":"Article 119230"},"PeriodicalIF":4.8,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420677","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":"Direct pathway of incorporating dietary nitrogen in shell-bound matrix of the planktic foraminifera Trilobatus sacculifer","authors":"Wei-Ning Fang ,&nbsp;Oscar Branson ,&nbsp;Er-Wen Yang ,&nbsp;Wen-Hui Chen ,&nbsp;Ren-Yi Cai-Li ,&nbsp;Howard J. Spero ,&nbsp;Jennifer Fehrenbacher ,&nbsp;Lael Vetter ,&nbsp;Charlotte LeKieffre ,&nbsp;Haojia Ren","doi":"10.1016/j.epsl.2025.119231","DOIUrl":"10.1016/j.epsl.2025.119231","url":null,"abstract":"<div><div>The stable isotopes of organic nitrogen (N) preserved within the fossil tests of foraminifera have been used to reconstruct past changes in surface ocean nitrogen cycling processes. Modern observations show temporal and spatial covariations of δ¹⁵N between planktic foraminifera and particulate organic matter in the surface ocean, suggesting that heterotrophic foraminifera record the N isotopic compositions of their diet. However, little is known about the underlying mechanisms of N translocation from diet into foraminiferal biomass (<em>i.e.</em>, intrashell protoplasm) and finally embedded within their mineralized shells. We investigate the pathways of N uptake from diet into foraminiferal calcite tests by feeding the planktic, dinoflagellate-bearing <em>Trilobatus sacculifer</em> with two strains of brine shrimp (<em>Artemia</em>) with different ¹⁵N/¹⁴N isotopic compositions, and monitoring the δ¹⁵N evolution of both biomass and shell-bound matrix. The two feeding groups show comparable results, that δ¹⁵N of both the biomass and shell-bound matrix evolve towards their diet sources without expressing trophic enrichment in δ¹⁵N. However, we observe that the δ¹⁵N of the biomass and shell-bound matrix exhibit distinct mixing behaviors. Biomass δ¹⁵N is well modelled as a mixture between the original biomass and newly metabolised dietary intake, suggesting <em>T. sacculifer</em> has a closed N system with minimum N leakage. Meanwhile, shell-bound δ¹⁵N quickly approaches the δ¹⁵N of the diet, and is offset from the biomass δ¹⁵N. This indicates a direct pathway of N incorporation from the diet into shell-bound organics during calcification, without significant exchange with the overall biomass pool.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"654 ","pages":"Article 119231"},"PeriodicalIF":4.8,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143421189","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":"Coeval formation of continental crust and cratonic mantle facilitated by surface material recycling in the Paleoarchean: Constraints from molybdenum isotopes","authors":"Sukalpa Chatterjee ,&nbsp;Arathy Ravindran ,&nbsp;Qasid Ahmad ,&nbsp;Om Prakash Pandey ,&nbsp;Martin Wille ,&nbsp;Klaus Mezger","doi":"10.1016/j.epsl.2025.119227","DOIUrl":"10.1016/j.epsl.2025.119227","url":null,"abstract":"<div><div>The formation of cratons was a fundamental process on Earth during the Archean. Cratons are characterized by a stable lithosphere consisting of felsic continental crust overlying a lithospheric mantle. The spatial and temporal relationship of these two distinct reservoirs can be reconstructed from mafic dyke swarms that are sourced from the cratonic mantle and intruded the Archean cratons over time. Trace element abundances of four dyke swarms that intruded the Singhbhum Craton between 2.8 Ga and 1.8 Ga combined with stable Mo and radiogenic Hf and Nd isotopes indicate that the crustal enrichment signature in the parental magma of the dykes was due to earlier enrichment of their respective mantle sources. The covariation of δ^98/95Mo with mobile/immobile element ratio indicate that hydrous melts originating from recycled surface-derived materials led to metasomatism in the mantle source region of the mafic dykes. A redox-dependent multicomponent element (Mo, Ce) and isotope (δ^98/95Mo, εHf_, εNd) mixing model affirms that the metasomatism of the Singhbhum cratonic mantle was facilitated by reduced low-degree melts derived from recycled sediments and hydrated mafic crust. The mixing model further suggests that the cratonic lithosphere of the Singhbhum Craton was metasomatized in the Paleoarchean around 3.44 Ga, which is synchronous with the formation of Singhbhum granitoids. This is one of the oldest geochemical indications of mantle metasomatism on Earth. The radiogenic isotopes and δ^98/95Mo reveal that even in the Paleoarchean, recycling of surface-derived reduced material at least locally by horizontal tectonics was active on Earth and this process played a critical role in the formation of stable cratons.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"654 ","pages":"Article 119227"},"PeriodicalIF":4.8,"publicationDate":"2025-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420676","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 spatio-temporal evolution of 182W and 142Nd in the Deccan-La Réunion plume","authors":"Josua J. Pakulla ,&nbsp;Jonas Tusch ,&nbsp;Eric Hasenstab-Dübeler ,&nbsp;Arathy Ravindran ,&nbsp;Mike W. Jansen ,&nbsp;Felipe P. Leitzke ,&nbsp;Purva Gadpallu ,&nbsp;Raymond A. Duraiswami ,&nbsp;Carsten Münker","doi":"10.1016/j.epsl.2025.119225","DOIUrl":"10.1016/j.epsl.2025.119225","url":null,"abstract":"<div><div>Variations of the short-lived decay products ¹⁸²W and ¹⁴²Nd that formed approximately during the first 60 and 500 million years after solar system formation are pivotal in our understanding of Hadean processes and homogenization of Earth's mantle. For example, a coupling of ¹⁴²Nd and ¹⁸²W anomalies for the Deccan-La Réunion plume has been previously suggested to mirror a combined involvement of core-mantle interaction and Hadean silicate material, possibly stored in Large Low Shear Wave Velocity Provinces (LLSVPs). However, the limited availability of such short-lived isotope data for basalts from the Deccan Volcanic Province (DVP) made it difficult to assess this model closely. In this study, we provide new combined µ¹⁴²Nd and µ¹⁸²W data for ten selected samples of the DVP and one TTG from the Dharwar Craton basement, now covering different mantle endmembers of the DVP. Additionally, we provide new µ¹⁴²Nd data for six volcanic rocks from La Réunion that were previously analyzed for ¹⁸²W. We do not find evidence for a correlation between µ¹⁴²Nd and µ¹⁸²W in contrast to previous suggestions. Our data show that the involvement of mantle lithosphere and crustal components influences the µ¹⁸²W compositions of the DVP samples. Values of µ¹⁸²W (-4.2 ± 3.0) of such contaminated DVP samples overlap with the compositional field of volcanic rocks from La Réunion (-4.9 ± 1.5). The asthenospheric endmember of the DVP displays resolvable larger µ¹⁸²W deficits as low as -12.0 ± 2.3. Additionally, the asthenospheric DVP endmember also displays more unradiogenic ²⁰⁶Pb/²⁰⁴Pb ratios and low Δ²⁰⁷Pb/²⁰⁶Pb compared to La Réunion lavas and DVP lavas that assimilated lithospheric material. With regards to the two endmember models previously proposed for W isotope anomalies in mantle plumes, neither core-derived W nor an ancient silicate component with anomalous ¹⁸²W can be completely ruled out at this stage. However, due to the covariation of Pb and W isotopes and lower W/Th ratios in asthenosphere-derived DVP lavas, we currently favour a recycled mafic restite component of Hadean age as a source for the ¹⁸²W deficits in the Deccan-La Réunion plume.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"653 ","pages":"Article 119225"},"PeriodicalIF":4.8,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313931","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":"Are long-lasting isotope trends independent from slab dynamics, upper-plate stress regime and crustal thickness? Insights from central Patagonia","authors":"Marie C. Genge ,&nbsp;César Witt ,&nbsp;Massimiliano Zattin ,&nbsp;Delphine Bosch ,&nbsp;Olivier Bruguier ,&nbsp;Stefano Mazzoli","doi":"10.1016/j.epsl.2025.119229","DOIUrl":"10.1016/j.epsl.2025.119229","url":null,"abstract":"<div><div>Understanding the interplay and impact of internal and external factors on magma composition is crucial for constraining crustal evolution, tectonic processes and global geochemical cycles in convergent continental margins. The integration of zircon isotope (Hf-O) and trace element analyses with U-Pb geochronology provides insights into temporal shifts in magma composition and reservoir evolution. However, debates persist regarding the role of external and internal factors in magma evolution, particularly in complex subduction zones. To address this issue, we examined detrital zircon samples from central Patagonia (45°S–48°S), which is renowned for extensive continental arc magmatism since the Late Triassic. With alternating phases of shallow- and steeply-dipping slab lasting &lt; 50 million years, and apparent minimal changes in crustal thickness until the Miocene, this region offers a valuable opportunity to study the influence of internal and external factors on magma composition changes through time. Our study unraveled long-term trends for Hf-O and some trace elements ratios spanning at least 70 Myr. Such trends appear to be primarily related with crustal thickness of the overriding plate, and only secondarily with slab dynamics or upper-crustal stress regime. During time spans characterized by a thin crust (Jurassic to late Paleogene), external forcing controlled magma depletion and enrichment trends. Depletion resulted from the solely or concurrent effects of depleted components addition from: (i) the upwelling of a moderately depleted mantle triggered by slab rollback (Jurassic – Early Cretaceous and late Paleogene), or (ii) opening of slab tear/window in adjacent regions (Late Cretaceous – early Paleogene), as well as (iii) melting of the altered oceanic crust (Early – Late Cretaceous) or (iv) subduction of sediments derived from the erosion of juvenile forearc units (Paleogene). Conversely, contribution of enriched units of the forearc may have triggered the gradual enrichment observed during the Paleogene. However, the sudden enrichment during the Neogene has been related to a more effective crustal assimilation process during the Miocene Andean orogeny, characterized by amphibole fractionation and thus moderate crustal thickening. Our findings revealed that, depending on crustal thickness, either internal or external factors control long-term arc magma evolution. Internal factors are dominant in thicker-crust settings, while external factors – enabling mantle upwelling, slab melt or sediment subduction, which in turn affect mantle wedge composition – govern thin-crust settings.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"653 ","pages":"Article 119229"},"PeriodicalIF":4.8,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143313930","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}