Earth and Planetary Science Letters最新文献

{"title":"Artifact of protracted zircon ages after high-temperature granulite-facies metamorphism","authors":"Shuaiqi Liu ,&nbsp;Guibin Zhang ,&nbsp;Simin Huang ,&nbsp;Shuzhen Wang","doi":"10.1016/j.epsl.2025.119603","DOIUrl":"10.1016/j.epsl.2025.119603","url":null,"abstract":"<div><div>The duration of high-temperature (HT) granulite-facies metamorphism, as inferred from zircon geochronology, provides key constraints on the thermal state and regional tectonic setting. However, zircon U−Pb ages and rare earth element (REE) systematics can be disturbed by HT metamorphism due to diffusive resetting. This study presents decoupled zircon ages and trace element data for HT–ultra-HT (UHT) granulitized eclogites and pelitic granulites from the central Himalaya. Two cases were observed: (1) zircons with the same U−Pb ages, but different textures and geochemical signatures; and (2) zircons with similar geochemical compositions, yet different U−Pb ages. Zircon U−Pb diffusion modeling shows that (U)HT thermal overprinting can modify the pre-existing metamorphic zircon within 5 Myr at temperatures of &gt;850 °C. In addition, the (U)HT granulite-facies overprinting can affect the REE patterns and result in the zircons having heavy REE-enriched patterns. We also quantitatively modeled the zircon geochemical variations in equilibrium with silicate melt and determined how these change with rock type. Europium anomalies in zircon associated with partial melting of pelitic granulite cannot be used as a proxy for the depth of crustal melting, whereas the zircon Eu anomalies related to eclogite melting are mainly affected by plagioclase content, which is a function of pressure. CI-chondrite-normalized Dy/Yb [(Dy/Yb)_N] ratios in zircons decrease and Lu/Hf ratios increase with garnet breakdown for both rock types. Zircon ages and geochemical features of granulitized eclogite and leucosomes constrain the transition time of eclogite-facies metamorphism to granulite-facies metamorphism occurred during 17−14 Ma. This period was previously recognized as the timing of peak pressure. Therefore, caution is required in dating UHT rocks, because the zircon ages possibly post-date the peak pressure stage. Furthermore, this study insists that the protracted zircon ages in HT–UHT granulite-facies rocks might be an artifact of disturbed zircon U–Pb and trace element systematics caused by zircon diffusive resetting.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"670 ","pages":"Article 119603"},"PeriodicalIF":4.8,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144926241","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":"Research on the geological characteristics of shallow layer and regional magma - impact evolution history at the navigation area on Chang'e-4 mission","authors":"Guangliang Zhang ,&nbsp;Bin Liu ,&nbsp;Shun Dai ,&nbsp;Xingguo Zeng ,&nbsp;Hongbo Zhang ,&nbsp;Xin Ren ,&nbsp;Wangli Chen ,&nbsp;Jingjing Zhang ,&nbsp;Qin Zhou ,&nbsp;Dawei Liu ,&nbsp;Wei Yan ,&nbsp;Renhao Tian ,&nbsp;Wenhui Wu","doi":"10.1016/j.epsl.2025.119613","DOIUrl":"10.1016/j.epsl.2025.119613","url":null,"abstract":"<div><div>The Chang'e-4 mission lander and the rover landed in the Von Karman impact crater in the South Pole Aitken (SPA) basin on the far side of the moon. Using the optical images and spectral data obtained from 57 exploration points during the 60 lunar months by the Chang'e-4 rover, we have acquired information on the shallow structure of the lunar soil and the composition of the lunar surface materials. The results show that the main demonstration types in the landing area are basalt, weathered deposits, and highland rocks. The lunar soil layer in the landing area can be divided into two categories in terms of surface morphology and deep thickness, namely, thin layer lunar soil with light gray, less gravel, and less alteration, and thick layer lunar soil with dark color, more gravel, and more alteration. It was found that they alternate and appear as strip like structures, extending in a northeast southwest direction. At the same time, research on spectral composition data shows that its composition is uniform, and the composition of the landing zone is consistent with that of the Finsen impact crater, but it contains more olivine and glass components. The shallow radar research results show that the deep part of the landing area is divided into four layers: weathered accumulation layer, gravel layer, coarse gravel layer, basalt basement layer, and bedrock layer. Based on the above results, we found that the landing zone can be divided into the following stages after the formation of the Von Kármán impact crater: the Imbrian basalt filling period, during which the basalt bedrock at the bottom of the Von Kármán impact crater was formed; Next is the Eratosthenian impact modification period, during which large impact craters were formed around it, and the Von Kármán impact crater was modified. The ejecta from nearby impact craters contributed to the accumulation and weathering products of the landmass to a certain extent.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"670 ","pages":"Article 119613"},"PeriodicalIF":4.8,"publicationDate":"2025-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933593","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":"Seismically induced kinking in quartz","authors":"Michel Bestmann ,&nbsp;Bernhard Grasemann ,&nbsp;Rüdiger Kilian ,&nbsp;John Wheeler ,&nbsp;Luiz F.G. Morales ,&nbsp;Andreas Bezold ,&nbsp;Giorgio Pennacchioni","doi":"10.1016/j.epsl.2025.119546","DOIUrl":"10.1016/j.epsl.2025.119546","url":null,"abstract":"<div><div>Deformed quartz veins next (1–1.5 m) to an exhumed pseudotachylyte-bearing (i.e. anciently seismic) fault within the Schobergruppe (Austroalpine Crystalline Complex, Eastern Alps) contain intensely kinked quartz grains. The monoclinic symmetry of kink bands is consistent with the dextral slip sense of the fault. Cathodoluminescence images show a very high density of intragranular, sub-planar, lamellae accompanied by nanometre-scale fluid-related porosity visible in electron backscatter orientation contrast. Based on the oscillating orientation variation across subgrain boundaries (misorientation angle 1–9°) these lamellae (oriented (sub)parallel to a rhomb plane and spaced 4–10 µm apart) are identified as short-wavelength undulatory extinction microstructures (SWUE). Transmission electron microscopy reveals a high degree of recovery (low dislocation density) across the SWUE. Only grains with SWUE oriented parallel to the vein boundary are kinked. Based on detailed microstructural and crystallographic analysis, we infer the following history of kinking evolution related to the seismic cycle: (I) Deformation lamellae formed at high differential stresses preceding, or associated with, seismic rupture propagation. The initial high dislocation density within deformation lamellae provided the mechanical anisotropy in quartz required for (II) the subsequent coseismic initiation of kinking. The lamellae acted as a geometric filter that only allowed <em>r</em> <em>&lt;</em> <em>a&gt;</em> slip of dislocations parallel to the lamellae. These athermal dislocations were able to glide fast over a relatively large distance before piling up and initiating kinking during the coseismic event. Progressive build-up of dislocations resulted in deformation bands which accumulated the final misorientation angle between host domain and kink domain. (III) Residual stress during post-seismic deformation induced dynamic re-arrangement of dislocations into sub-parallel subgrain boundaries which now characterize the kink band boundary region. We suggest that kinking in quartz potentially indicates coseismic deformation and is an important mechanism for incipient strain accommodation during high strain rates.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"670 ","pages":"Article 119546"},"PeriodicalIF":4.8,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144921291","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":"Control of crustal strength by crustal melt presence and removal and its influence on the deformation mode in the Himalayan orogen","authors":"Yipeng Li ,&nbsp;Delores M. Robinson ,&nbsp;Lin Ding ,&nbsp;Kathryn Metcalf","doi":"10.1016/j.epsl.2025.119593","DOIUrl":"10.1016/j.epsl.2025.119593","url":null,"abstract":"<div><div>Understanding how crustal strength varies and interplays with tectonic processes is critical for continental orogeny studies. We combine thermodynamic and rheological calculations with wedge mechanics to investigate how Himalayan Cenozoic leucogranite melting and melt-removal affect crustal strength and thereby influence large-scale tectonism. Integrating the previous studies of Himalayan crustal deformation, tectono-metamorphism, and paleo-elevation reconstruction, our results reveal three key phases: 1) Rising geothermal gradients during ∼60-30 Ma crustal thickening weakened the mid-lower crustal strength that potentially triggers the initiation of the Himalayan structural discontinuities since ∼40 Ma, replacing the Tethyan fold-thrust belt as the primary convergent strain accommodator along the Himalaya; 2) Early-stage broad leucogranite melting during ∼30-20 Ma weakened the mid-lower crustal strength, producing a supercritical wedge that promoted across-strike lengthening of low-elevation Himalayan taper accommodated by normal faulting and far-traveled long basal thrust sheets since ∼30–25 Ma; 3) Melt-removal and extraction coeval with widespread leucogranite intrusion during ∼20-10 Ma substantially strengthened the mid-lower crust, transitioning the wedge from supercritical to subcritical states, thereby maintaining the growing high-elevation taper and shifting deformation mode from long thrust sheets to foreland-propagated short imbrication/duplex thrust sheets. A relatively strong Himalayan mid-lower crust, existing both before broad melting and after melt-removal, rims the softer South Tibet crust at depth, likely influencing far-field tectonism. These observations highlight how the transition from melt-presence to melt-removal significantly affects orogenic crustal strength controlling major tectonism and demonstrate that the vertical rheological structure during melt-removal differs substantially from conventional quartz and feldspar analogs.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"670 ","pages":"Article 119593"},"PeriodicalIF":4.8,"publicationDate":"2025-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144918013","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 new tektite strewn field in Australia ejected from a volcanic arc impact crater 11 Myr ago","authors":"Anna Musolino ,&nbsp;Pierre Rochette ,&nbsp;Jean-Alix Barrat ,&nbsp;Fred Jourdan ,&nbsp;Bruno Reynard ,&nbsp;Bertrand Devouard ,&nbsp;Valerie Andrieu ,&nbsp;Jérôme Gattacceca ,&nbsp;Vladimir Vidal","doi":"10.1016/j.epsl.2025.119600","DOIUrl":"10.1016/j.epsl.2025.119600","url":null,"abstract":"<div><div>This study re-evaluates the anomalous subgroup of australites known as high Na/K (HNa/K) tektites (Chapman and Scheiber, 1969). Although previous compositional and isotopic analyses suggested a distinct origin, the group has never been formally recognized as a separate tektite strewn field. We present new data from six HNa/K tektites, complementing the eight specimens already described. We conducted a comprehensive investigation, including petrographic (optical and electron microscopy, and micro-X-ray tomography), geochemical (major and trace element compositions, Sr-Nd isotopic composition, ⁴⁰Ar/³⁹Ar dating), and spectroscopic (for the identification of inclusions) analyses. We concluded that the HNa/K tektites originated from a separate impact event compared to Australasian tektites; they have an andesitic to dacitic composition and arc-related trace element signatures. Lechatelierite (and phosphate) inclusions as well as high levels of chondritic contamination support an impact origin, for which we provide a more precise ⁴⁰Ar/³⁹Ar age: 10.76 ± 0.05 Ma. For now, Sr-Nd isotopic data and trace elements composition point to three possible sources associated with active volcanic arcs: Luzon (Philippines), Sulawesi (Indonesia), and the Bismarck region (Papua New Guinea). Systematic petrographic and geochemical differences observed between tektites from the western and eastern parts of the ∼900-km-wide hypothesized strewn field (located in Southern Australia) may help to constrain the location of the source crater, but they need to be confirmed by the study of more specimens. We propose the name “Ananguite” for this new group of tektites.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"670 ","pages":"Article 119600"},"PeriodicalIF":4.8,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144918012","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":"The “lost” aqueous supercritical fluids recorded in highly refractory mantle peridotites","authors":"Haochen Duan ,&nbsp;Yunpeng Dong ,&nbsp;Huimin Yu ,&nbsp;Wenyu Wang ,&nbsp;Fang Huang","doi":"10.1016/j.epsl.2025.119597","DOIUrl":"10.1016/j.epsl.2025.119597","url":null,"abstract":"<div><div>Supercritical fluids, including silicate-enriched and aqueous varieties, are crucial for material circulation and energy exchange within Earth’s layers. Although silicate-enriched supercritical fluids are well-documented in ultra-high-pressure rocks, the nature of aqueous supercritical fluids remains elusive because they are easily “lost” during transport processes and their signals are often obscured in natural materials. Here, we report the geochemical compositions of the ultra-refractory mantle wedge peridotites that underwent extreme melt extraction and metasomatism to identify aqueous supercritical fluid signatures. These peridotites are enriched in fluid-mobile elements, and light rare earth and high-field strength elements, implying metasomatism by silicate-depleted aqueous rather than silicate-enriched supercritical fluids. The δ^138/134Ba of peridotites range from -0.11‰ to +0.52‰, indicating that the aqueous supercritical fluids may be derived from a cold subducted plate or through the silicate loss of silicate-enriched supercritical fluids. These water-enriched liquids can play a key role in cryptical metasomatism and long-distance element migration, providing new insights into the dynamics of Earth’s interior.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"670 ","pages":"Article 119597"},"PeriodicalIF":4.8,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907599","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":"Enhanced earthquake hazard in the Lut Block Region, Iran due to the stress evolutions since 1968","authors":"Fatih Uzunca ,&nbsp;Murat Utkucu ,&nbsp;Süleyman Sami Nalbant ,&nbsp;Hatice Durmuş","doi":"10.1016/j.epsl.2025.119601","DOIUrl":"10.1016/j.epsl.2025.119601","url":null,"abstract":"<div><div>Time-dependent stress changes of the M_W≥6.3 earthquakes in the Lut Block Region following the 1968 Dasht-e Bayaz (M_W=7.1) earthquake are calculated to investigate earthquake interactions and hazards. Stress changes are computed simultaneously for all earthquakes using different Earth rheology models with varying viscosities. Results indicate that lower crustal viscosity influences viscoelastic (VE) postseismic stress changes more significantly than upper mantle viscosity. Regardless of the rheology model used, positive VE postseismic stress changes are observed at the hypocenters of the 1979 Boznabad, Korizan, and Khuli-Buniabad earthquakes, whereas negative VE postseismic stresses are computed for the 1978 Tabas-e Golshan and 2010 Rigan earthquakes. Strong VE postseismic stress loading at the 1979 Khuli-Buniabad and 1998 Fandoqa earthquake hypocenters reverses negative coseismic stresses into positive values. Conversely, at the 1981 Sirch and 2003 Bam earthquake hypocenters, positive coseismic stresses are partially offset by negative VE postseismic stresses, though not enough to produce an overall negative stress state. The Nayband, Avaz-Gazik and East Chahqanbar faults, eastern parts of the Dasht-e Bayaz and Doruneh faults, and Bam and Golbaf fault extremities are exposed to relatively strong coseismic and VE postseismic stress loads imparted by the studied earthquakes. Stress evolutions from 1968 to 2045 at the selected points indicate general stress increases, leading to estimated seismic cycle advances of 23–194 years for the southern Nayband fault (a proposed seismic gap) and 132–352 years for the eastern Doruneh fault.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"670 ","pages":"Article 119601"},"PeriodicalIF":4.8,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907597","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":"Magnesium, iron, and calcium isotope signatures of Chicxulub impact spherules: Isotopic fingerprint of the projectile and plume thermodynamics","authors":"Courtney Jean Rundhaug ,&nbsp;Martin Schiller ,&nbsp;Martin Bizzarro ,&nbsp;Zhengbin Deng ,&nbsp;Hermann Dario Bermúdez","doi":"10.1016/j.epsl.2025.119599","DOIUrl":"10.1016/j.epsl.2025.119599","url":null,"abstract":"<div><div>The Cretaceous-Paleogene boundary (KPB) represents a massive extinction event in Earth's history, probably triggered by the Chicxulub asteroid impact ∼66 Ma. The event dispersed vast volumes of ejecta materials including exceptionally preserved impact spherules in the Gorgonilla Island KPB section. Previous work identified three populations of spherules at Gorgonilla: 1) ballistically transported molten spherules, 2) a mixture of molten and condensed spherules dispersed by the expansion of a high-temperature, turbulent cloud (the \"pyrocloud\"), and 3) tiny droplets condensed from the plume (the \"fireball layer\"). We determine the Mg, Fe, and Ca isotopic compositions of pristine spherules to better understand the evaporation and condensation thermodynamics within the pyrocloud. We detect enrichment in mass bias corrected µ⁴⁸Ca and µ²⁶Mg* isotope signatures from the terrestrial value corresponding to an impactor contribution of ∼17–25%, most likely from a CM or CO chondrite-like asteroid. The mass-dependent δ²⁵Mg and δ⁵⁶Fe compositions are generally light or unfractionated, suggesting incomplete recondensation as the pyrocloud cooled and expanded. Combined δ²⁵Mg and δ⁵⁶Fe signatures reveal decoupling of these isotope systems, likely due to differing condensation rates. Thus, we calculate a higher average condensation rate of Fe than Mg, reflecting the thermodynamic decoupling and more complete recondensation signatures of Fe in the pyrocloud vapor. While we uncover information about the evaporation and condensation thermodynamics in the pyrocloud, the exact formation mechanisms of the complete suite of spherules remain complex with some spherules potentially forming from multiple mechanisms, including recondensation and splash–melting.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"670 ","pages":"Article 119599"},"PeriodicalIF":4.8,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144907598","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":"Viscous heating in sediments as a 'Zeroing' mechanism in luminescence dating of sand dikes for paleoseismological investigations","authors":"A.K. Tyagi ,&nbsp;D. Kumar ,&nbsp;M.K. Murari ,&nbsp;R.N. Singh ,&nbsp;A.K. Singhvi","doi":"10.1016/j.epsl.2025.119578","DOIUrl":"10.1016/j.epsl.2025.119578","url":null,"abstract":"<div><div>This contribution examines the possibility of directly determining the timing of paleoseismic events by luminescence dating of sediments in sand dikes. Sand dikes are water escape structures (liquefaction features) formed in soft sediments due to the passage of seismically generated Rayleigh waves. Blending earlier studies of a crack dilatation model for the creation of sand dikes (Levi et al., 2008) and the studies on sonication of crystal slurries (Eddingsaas and Suslick, 2006), we posit that kinematic viscosity during the injection of liquefied sediments leads to a local transient heating of the injected material. Theoretical analysis of the injection process developed in this study shows that the instantaneous viscous flow of a sediment-water mixture through cracks in the overlying sedimentary strata can generate local temperatures of 350 °C or even more. Such temperatures can reset the luminescence signal of quartz grains in the liquefied sediments. Thereafter, the luminescence signal acquired by the quartz grains from their ambient natural radiation environment enables direct dating of these sediments; i.e. the timing of the causal earthquake. Given that the injection velocity (and hence the temperature rise) is highest at the centre of a dike, the sampling was from the core region of dikes.</div><div>Changes in the thermoluminescence sensitivity of the 110 °C glow peak of quartz (Sunta and David, 1982) were used to confirm that the viscous heating during sand dike formation did result in temperatures ≥ 350 °C. Stratigraphic consistency of luminescence ages of the dikes, the source sediments and their concordance with the published radiocarbon ages confirms the applicability of luminescence for their dating and provide evidence of three large earthquakes ∼0.30 ± 0.03, 1.0 ± 0.10 and ≥ 1.5 ka ago.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"670 ","pages":"Article 119578"},"PeriodicalIF":4.8,"publicationDate":"2025-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144911665","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":"Sand encased by fine-grained sediment regulates methane migration through the gas hydrate stability zone","authors":"Jiliang Wang ,&nbsp;Ang Li ,&nbsp;Wei Zhang ,&nbsp;Jin Sun ,&nbsp;Jiecheng Zhang ,&nbsp;Xueqing Zhou ,&nbsp;Shiguo Wu","doi":"10.1016/j.epsl.2025.119595","DOIUrl":"10.1016/j.epsl.2025.119595","url":null,"abstract":"<div><div>Sand encased by fine-grained sediment can often be present in the shallow subsurface along continental margins. However, its role in methane migration through the gas hydrate stability zone (GHSZ) in mud-dominated sediments has not been fully investigated. Here, we use 3-D seismic and drilling data in the northern South China Sea, and numerical modeling to examine how sand encased by fine-grained sediment regulates methane migration through the GHSZ. Our analysis of well logging data at Site W01, an area of active methane emission, reveals the occurrence of a 12.5-m-thick sand layer that contains gas hydrates within the GHSZ. The 3-D seismic data show that there are two gas chimneys, one located below and the other above the sand layer at Site W01. The lower gas chimney exhibits a high-amplitude rim at the base of the sand, suggesting that it contributes methane for gas hydrate formation within the sand. The upper gas chimney extends from the sand layer to the seafloor, acting as a pathway for the current methane emissions. The sand probably arrests the upward propagation of the lower gas chimney and captures upward-migrating methane. If the overpressure generated by the methane flux is insufficient to breach the overlying fine-grained sediment, the methane would be diverted to migrate laterally within the sand. Meanwhile, a highly heterogeneous distribution of gas hydrates forms in the sand, restricting further methane flow. As hydrate accumulation clogs the sand and creates a self-sealing effect, the pore pressure gradually increases due to the continuous accumulation of free methane gas. Eventually, this pressure can lead to hydraulic fracturing, resulting in the formation of a new gas chimney in the overlying fine-grained sediment. This study provides new insights into the characteristics of gas hydrate reservoirs in sand and the migration of free methane gas through the GHSZ along continental margins.</div></div>","PeriodicalId":11481,"journal":{"name":"Earth and Planetary Science Letters","volume":"669 ","pages":"Article 119595"},"PeriodicalIF":4.8,"publicationDate":"2025-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144904292","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}