{"title":"Coupled nitrogen and iron redox cycling in the Paleoarchean: Insights from nitrogen isotope signatures of the ca. 3.25 Ga Mapepe Formation, Barberton Greenstone Belt","authors":"Kento Motomura , Takashi Sano , Shoichi Kiyokawa","doi":"10.1016/j.epsl.2025.119659","DOIUrl":"10.1016/j.epsl.2025.119659","url":null,"abstract":"<div><div>Earth’s surficial environments and biosphere have co-evolved through geological time. Constraining past biological activity is thus crucial for understanding Earth’s evolution. However, the nature of microbial metabolic processes and their evolution in the Archean ocean remain unclear. Here, we investigated the carbon and nitrogen cycles in the Paleoarchean ocean using δ<sup>13</sup>C<sub>org</sub> and δ<sup>15</sup>N values of shales from the ca. 3.25 Ga Mapepe Formation of the Fig Tree Group in the Barberton Greenstone Belt, South Africa. Hydrogen, carbon, and nitrogen contents of kerogen extracts were also measured, along with δ<sup>15</sup>N<sub>kerogen</sub> values, to assess the potential effects of metamorphism on the isotope data. The molar H/C ratios suggest the studied shales have been metamorphosed at the greenschist to amphibolite facies. The δ<sup>15</sup>N<sub>bulk</sub> values are consistently positive throughout the studied section, with a notable increase to as high as +8.5‰ in the stratigraphic interval between 57 m and 63 m. Within this high-δ<sup>15</sup>N<sub>bulk</sub> interval, total organic carbon contents and δ<sup>15</sup>N<sub>kerogen</sub> values increase to approximately 4 wt.% and +6‰, respectively, while δ<sup>13</sup>C<sub>org</sub> values decrease by ∼5‰. Petrographic observations indicate the iron is present mainly as iron oxides rather than sulfides in the studied shales, consistent with deposition under sulfate-poor ferruginous conditions. The Fe/Al ratios exhibit a positive correlation with δ¹⁵N<sub>kerogen</sub> values (R² = 0.49) and a negative correlation with δ¹³C<sub>org</sub> values (R² = 0.37). These observations suggest anaerobic oxidation of ammonium and methane coupled with iron reduction. Since ammonium oxidation can occur via both biotic and abiotic pathways, further investigations are needed to clarify the role of organisms in the coupled nitrogen and iron cycling during the Paleoarchean.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"671 ","pages":"Article 119659"},"PeriodicalIF":4.8,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263209","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}
Wenshuai Li , Ryoichi Nakada , James McManus , Brian A. Haley , Mohsen Shakouri , Fulai Li , Yoshio Takahashi
{"title":"Decoupling cerium isotope fractionation from cerium anomalies in marine sediments","authors":"Wenshuai Li , Ryoichi Nakada , James McManus , Brian A. Haley , Mohsen Shakouri , Fulai Li , Yoshio Takahashi","doi":"10.1016/j.epsl.2025.119652","DOIUrl":"10.1016/j.epsl.2025.119652","url":null,"abstract":"<div><div>Cerium (Ce) stable isotopes, combined with Ce anomalies, serve as potential proxies for reconstructing Earth’s past redox conditions. However, the behavior of Ce isotopes and Ce anomalies across different oceanic redox environments remains underexplored. This study presents a Ce anomaly and Ce isotope dataset of marine sediments from a range of modern oceanographic regimes, including anoxic continental margins and oxic Equatorial Pacific environments. By integrating bulk sediment geochemistry, sequential extraction, and X-ray absorption spectroscopy data, we reveal the decoupling between Ce stable isotope values (δ<sup>142</sup>Ce) and Ce anomalies (Ce/Ce*). Margin sediments exhibit negative Ce anomalies (0.48 to 0.96) that display a negative correlation with δ<sup>142</sup>Ce (-0.05 to 0.12 ‰), which are close to or higher than the upper continental crust value (-0.03±0.06 ‰). This relationship results from the influence of seawater-derived REEs through authigenic phosphates and organic matter, as well as clastic inputs. In contrast, Equatorial Pacific sediments exhibit positive Ce anomalies (1.05 to 1.23) that are positively correlated to their δ<sup>142</sup>Ce values (0.08 to 0.16 ‰), which exceed the upper crust baseline. This pattern is attributed to Mn(IV)-oxide-driven oxidative adsorption of Ce. Here, we purpose a first-order estimate for the δ<sup>142</sup>Ce value in bottom seawater of the Equatorial Pacific (about 0.3 to 0.4 ‰). These findings enhance our understanding of marine Ce geochemistry and underscore the importance of integrating Ce anomalies with Ce isotope signatures for paleoceanographic redox reconstructions.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"671 ","pages":"Article 119652"},"PeriodicalIF":4.8,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145263210","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}
Morgan T. Jones , Lars E. Augland , Maria Ovtcharova , Ella W. Stokke , Morgan Ganerød , Sverre Planke
{"title":"New constraints on the absolute age and duration of the Paleocene – Eocene Thermal Maximum (PETM) from ash layer +19 in Denmark","authors":"Morgan T. Jones , Lars E. Augland , Maria Ovtcharova , Ella W. Stokke , Morgan Ganerød , Sverre Planke","doi":"10.1016/j.epsl.2025.119643","DOIUrl":"10.1016/j.epsl.2025.119643","url":null,"abstract":"<div><div>Precise age constraints for the onset and duration of the Paleocene–Eocene Thermal Maximum (PETM) are essential for understanding the mechanisms that triggered and sustained this major climate perturbation. However, establishing a precise PETM geochronology is complicated by uncertainties in orbital tuning and a current lack of precise radiometrically dated marker horizons. An early Eocene rhyolitic ash layer named +19 is a promising marker horizon due to its distinct geochemistry, its occurrence in key offshore archives, and well-preserved outcrops in Denmark such as Stolleklint, where it conformably overlies PETM strata. We present a new high-precision U-Pb zircon age of 55.331 ± 0.053/(0.060)/[0.080] Ma for ash +19, supported by a new Ar-Ar age of 55.424 ± 0.115/(0.116)/[0.320] Ma within uncertainty. The ash +19 U-Pb age enables direct comparison with ash SB01–1 in Svalbard that was erupted during the PETM carbon isotope excursion (CIE), yielding a 454 ± 90 kyr interval between the two layers. This provides a robust geochronological link from the PETM to ash +19 that is independent of stratigraphic interpretations. Using end-member PETM durations (94–170 kyr), we estimate the time between the PETM onset and ash +19 as 528–604 ± 102 kyr, which is significantly shorter than the 862 ± 20 kyr interval derived from astronomical tuning. Adopting the longer helium isotope-based PETM duration yields an onset age of 55.935 ± 0.102 Ma, with a CIE recovery end at 55.700 Ma. A shorter PETM duration requires a younger PETM onset age. The positive ash series in Denmark, correlating with the offshore Balder Formation, is now constrained to a 250 kyr interval between 55.367 and 55.117 ± 0.080 Ma. This refined age model provides a robust framework for testing and improving early Eocene astronomical time scales.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"671 ","pages":"Article 119643"},"PeriodicalIF":4.8,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217904","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}
Chen Chen , Eric Gayer , Jérôme Gaillardet , Louis A. Derry , Pascale Louvat , Julien Bouchez , Zhangdong Jin , Reika Yokochi
{"title":"Enhanced weathering by multiscale destabilization of volcanic islands","authors":"Chen Chen , Eric Gayer , Jérôme Gaillardet , Louis A. Derry , Pascale Louvat , Julien Bouchez , Zhangdong Jin , Reika Yokochi","doi":"10.1016/j.epsl.2025.119649","DOIUrl":"10.1016/j.epsl.2025.119649","url":null,"abstract":"<div><div>Réunion Island, a volcanic basaltic island situated in the Indian Ocean, is a well-known hotspot of weathering and erosion with particularly intense bedrock landslides. We estimated the contribution of large landslides to the dissolved load in the main rivers across Réunion Island using a mixing model, suggesting a significant enhancement of chemical weathering associated with landslides. Landslides can contribute to a decadal chemical weathering flux of up to 69 t/km<sup>2</sup>/yr, accounting for 82% of the weathering flux in one of Réunion's basins. Overall, chemical weathering in Réunion Island is predominantly driven by landslides, accounting for approximately 60% of the weathering flux. Notably, landslide-associated weathering can be promoted by intense precipitation events. We propose that large landslides on Réunion Island favor the exposure of both fresh and hydrothermal minerals to water, thereby promoting chemical weathering. Since these hydrothermal minerals were formed by fluid-rock reactions at an earlier stage of the volcano's evolution, our results highlight the cannibalistic nature of weathering in Réunion Island. As a consequence, river chemistry tends to overestimate present-day chemical weathering rates and associated <span><math><msub><mrow><mi>CO</mi></mrow><mrow><mn>2</mn></mrow></msub></math></span> consumption in Réunion Island. We expect this conclusion to hold true for other volcanic settings as well. Further work on the weathering of basaltic rocks based on river chemistry should therefore take into account the geomorphological evolution of volcanic edifices, the only truly integrated approach to assess the climatic impact of the emplacement of volcanic rocks on Earth.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"671 ","pages":"Article 119649"},"PeriodicalIF":4.8,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217903","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":"Humidity dependent frictional properties of single crystal quartz at low to high slip velocities","authors":"Akito Tsutsumi , Hirotaka Iida , Yuko Onoe , Akira Miyake","doi":"10.1016/j.epsl.2025.119648","DOIUrl":"10.1016/j.epsl.2025.119648","url":null,"abstract":"<div><div>The frictional properties of synthetic quartz were investigated under humid (relative humidity, RH of 5–80 %) and nominally dry (≤3 % RH) conditions at a constant normal stress of 1.5 MPa and at various slip velocities of 0.005–105 mm/s. In slide–hold–slide tests performed after an initial sliding phase at 105 mm/s, the amount of frictional aging was found to increase with RH. The steady-state friction of quartz shows negative velocity dependence; steady-state friction decreases for an increase in slip velocity under all tested humidities. Notably, steady-state friction increases with RH in the specific range of velocity from ∼10 μm/s to 1 mm/s. The steady-state value of friction in quartz under humid conditions can be viewed as a combination of its intrinsic dry friction and the increased friction resulting from moisture-assisted strengthening mechanisms. The humidity dependence observed for aging and steady-state friction, respectively, is pronounced at low humidity levels (≤∼20 % RH) but becomes moderate at higher humidity levels (>∼20 % RH) for both cases. This trend suggests that similar fundamental frictional mechanisms govern the humidity dependence of frictional aging and steady-state values of friction at slow- to high-velocities. Transmission electron microscopy of the fault zone under steady-state sliding shows that fault-zone material mainly consists of amorphous silica, domains of which are composed of ∼0.5 μm-thick ultrathin layers. The formation of capillary water bridges around asperities with nanometer-scale surface roughness composed of amorphous silica grains might explain the humidity-dependent friction behavior of quartz.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"671 ","pages":"Article 119648"},"PeriodicalIF":4.8,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145217902","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}
Bijaya B Karki , Colin Jackson , Ekanshu Mallick , Abin Shakya , Dipta B Ghosh , Gabriele Morra
{"title":"A comparative study of nitrogen incorporation in silicate, metallic, and bulk earth melts at high pressure","authors":"Bijaya B Karki , Colin Jackson , Ekanshu Mallick , Abin Shakya , Dipta B Ghosh , Gabriele Morra","doi":"10.1016/j.epsl.2025.119653","DOIUrl":"10.1016/j.epsl.2025.119653","url":null,"abstract":"<div><div>Nitrogen as the dominant volatile element of the atmosphere is also expected to exist underneath the Earth’s surface. Its interior budget and distribution may have largely been set early on by the core formation and other processes that led to apparent volatile depletion in the terrestrial planet. To better understand how nitrogen may have behaved during the accretion stages when proto-Earth experienced multiple episodes of magma ocean environments, we report a first-principles computational study of nitrogen incorporation in silicate melts over wide pressure range 0 to 125 GPa (3000 to 5000 K), as well as in iron-rich metallic melt and bulk Earth-like melt at selected conditions. The results show that the speciation of nitrogen in silicate melts at low pressures consists of almost entirely N<sub>2</sub> molecules with interstitial occupancy. As pressure increases, nitrogen interacts increasingly with the silicate network and bonds with iron more strongly than with any other cations (Mg, Si, Ca, Al, and Ni) present in the melt. Both pressure and reducing conditions help nitrogen chemically dissolve as nitride species thus promoting nitrogen retention of possible deep-seated dense silicate melts in the mantle. Metallic liquid incorporates nitrogen by bonding with iron with weak or no interactions with itself or with other impurities. The simulated bulk Earth melt system shows a phase segregation to form an iron-rich cluster which is surrounded by a silicate region. The metal-silicate partition coefficient of nitrogen evaluated using the relevant local coordination statistics from the two-phase system is ∼31 at 30.5 GPa (3000 K, IW-3.1), ∼18 at 37.1 GPa (4000 K, IW-2.2), and ∼24 at 131 GPa (5000 K, IW-2.1) which are generally consistent with the measured trends. Based on the predicted strong preferential partitioning to the metallic liquid, we argue that while nitrogen may be depleted from the silicate mantle, it may be sequestered in the core.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"671 ","pages":"Article 119653"},"PeriodicalIF":4.8,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145156055","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}
Pingping Huang , Nigel T. Penna , Peter J. Clarke , Volker Klemann , Zdeněk Martinec , Yoshiyuki Tanaka
{"title":"Upper mantle anelasticity and its time dependence resolved by GPS in 3-D ocean tide loading displacements","authors":"Pingping Huang , Nigel T. Penna , Peter J. Clarke , Volker Klemann , Zdeněk Martinec , Yoshiyuki Tanaka","doi":"10.1016/j.epsl.2025.119644","DOIUrl":"10.1016/j.epsl.2025.119644","url":null,"abstract":"<div><div>Ocean tide loading (OTL) refers to the Earth's deformational response to periodic ocean mass redistributions driven by astronomical tides. This transient deformation likely involves anelasticity, which is associated with energy dissipation and plays a crucial role in understanding Earth's deformation across various temporal scales. However, anelastic contributions to OTL are minor (submillimetre-to-millimetre scale) relative to elastic OTL deformation and are comparable in magnitude to the influence of lateral heterogeneities in crust and upper mantle elasticity. Because of this, detecting and isolating anelastic OTL deformation remains challenging. Here, by analysing high-accuracy (0.2 – 0.4 mm) Global Positioning System (GPS) data from 255 sites across western Europe, and comparing with OTL forward modelling results from advanced 3-D elastic and anelastic Earth models incorporating sediments, we unambiguously demonstrate anelastic OTL displacements, in both horizontal and vertical directions. Our findings highlight the necessity of incorporating anelasticity into geodynamic models, particularly for processes operating at sub-seismic frequencies, and into a unifying viscoelastic law for modelling Earth deformations across multiple timescales. Furthermore, using GPS observations and realistic 3-D models, we constrain anelastic parameters for Earth’s upper mantle. These parameters reveal the weakening or dispersion of upper-mantle shear modulus, by up to 20 % at semi-diurnal tidal frequencies compared to its 1 Hz value in the Preliminary Reference Earth Model (PREM), and constrain the time dependence of this weakening. Our results support the application of OTL observations for constraining Earth’s anelasticity in the sub-seismic frequency range.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"671 ","pages":"Article 119644"},"PeriodicalIF":4.8,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145156054","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 lower mantle origin for the young mare basalts returned by Chang'e-5?","authors":"Runwu Li , Ming Tang , Jiaxi Wang","doi":"10.1016/j.epsl.2025.119650","DOIUrl":"10.1016/j.epsl.2025.119650","url":null,"abstract":"<div><div>The samples returned by the recent Chang’e-5 (CE-5) mission confirmed active lunar magmatism at least two billion years ago, which challenged the long-held view of an inactive Moon through much of its lifespan. However, the origin of this extended lunar magmatism remains mysterious. The CE-5 lunar soil and basalt fragments exhibit a strong fractionation between middle and heavy rare earth elements, a phenomenon rarely observed in the Apollo samples. We confirm this fractionation as a primary magmatic signature with measurements of the pyroxenes. By coupling phase equilibria modeling and element partitioning calculations, we show that this fractionation can only be produced if the magma source contained ∼5-10% garnet at a minimum depth of ∼700 km. We suggest the primary CE-5 magma may have originated from the lunar lower mantle. For melting to occur, one possibility is that convection may have been sustained in the deep lunar mantle until at least two billion years ago. Alternatively, the CE-5 magma may have tapped the melt-bearing layer near the core, as indicated by recent seismic observations.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"671 ","pages":"Article 119650"},"PeriodicalIF":4.8,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118893","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}
Ze Liu , Oliver Jagoutz , Zoe Molitor , Jahandar Ramezani , Di-Cheng Zhu
{"title":"Crustal section in the New England Appalachians records polybaric fractional crystallization-driven magma differentiation","authors":"Ze Liu , Oliver Jagoutz , Zoe Molitor , Jahandar Ramezani , Di-Cheng Zhu","doi":"10.1016/j.epsl.2025.119647","DOIUrl":"10.1016/j.epsl.2025.119647","url":null,"abstract":"<div><div>Ultramafic-mafic cumulates in the lower crust suggest that fractional crystallization (FC) drives the differentiation of primitive basaltic arc melts to intermediate compositions. Polybaric FC in the middle to upper crust may further evolve melts to silicic compositions, predicting compositional stratification with depth. However, such stratification is not observed in exposed arc sections. We investigate the Kinsman suite in the New England Appalachians, which exhibits depth-dependent compositional stratification, offering a critical test of the polybaric FC model. The Kinsman suite could originate from (1) polybaric FC of intermediate melts derived primarily from primitive arc melts with a minor contribution from crustal metasedimentary rocks, or (2) metasedimentary anatexis with selective entrainment or unmixing of peritectic minerals. Focusing on the Cardigan pluton (emplaced at ∼1 to 7 kbar, ∼406–403 Ma), the largest magma body within the Kinsman suite, we observe systematic increases in SiO<sub>2</sub> and Rb and decreases in MgO, FeO<sub>total</sub>, Al<sub>2</sub>O<sub>3</sub>, CaO, Sr, Ba, Sc, and Yb with decreasing emplacement depth. This compositional stratification, coupled with field evidence of cumulates, a continuous evolution of mineral geochemistry, and thermodynamic modeling, support continuous polybaric FC in the middle to upper crust of the Acadian arc. Zircon Hf isotopes indicate a common magma source for the Kinsman suite and contemporaneous ultramafic-mafic cumulates in northeastern Connecticut, with ∼65–95% contribution from primitive arc melts and ∼5–35% from crustal metasedimentary rocks. These findings highlight the Kinsman suite as a compelling example of polybaric FC in a continental arc, providing key insights into the magma differentiation and granite formation in the middle to upper crust.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"671 ","pages":"Article 119647"},"PeriodicalIF":4.8,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118894","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":"Gravity-driven fold-thrust belt at the Martian dichotomy","authors":"F. Carboni , O. Karagoz , J.B. Ruh , T. Kenkmann","doi":"10.1016/j.epsl.2025.119645","DOIUrl":"10.1016/j.epsl.2025.119645","url":null,"abstract":"<div><div>The origin and evolution of the Martian dichotomy is one of the most enigmatic topics in Mars geological history. Its morphological variations suggest how it undergone different geological events, which reshaped the dichotomy differently. The eastern dichotomy, in the Nilosyrtis Mensae, is the only location where there is clear evidence of extensional structures in the highlands and parallel compressional structures in the adjacent southern lowlands. Both are roughly aligned parallel to the dichotomy and their origins are still debated. Here, we investigate the hypothesis that these faults are linked to gravity-driven deformation, occurred during the Late Noachian – Early Hesperian. Remote sensing geological mapping, integrated with 2D kinematic and numerical modeling, supports the possibility that extension in the highlands and along the dichotomy is kinematically linked to compression ∼800 km in the southern lowlands. The link occurs through a common basal detachment, which developed from the hard-link between a shallower frictional detachment in the highlands and a deeper viscous detachment in the lowlands. This hypothesis also provides insights into the origin and evolution of both the dichotomy and the lowlands, supporting the hypothesis of a giant Borealis northern impact. Such an impact promoted the formation of a magma pond followed by precipitation of evaporites from an ancient short-lasting shallow hypersaline sea, which was later reorganized by subsequent impacts and buried beneath volcanic deposits.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"671 ","pages":"Article 119645"},"PeriodicalIF":4.8,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118904","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}