Earth-Science Reviews最新文献

{"title":"A Middle Devonian fluvial-delta plain complex from eastern Yunnan, South China: Insights into co-evolution between environments and organisms in an early non-marine system","authors":"Junjun Song ,&nbsp;Xiaole Zhang ,&nbsp;Sha Li,&nbsp;Wenkun Qie,&nbsp;Yi Wang,&nbsp;Honghe Xu","doi":"10.1016/j.earscirev.2025.105223","DOIUrl":"10.1016/j.earscirev.2025.105223","url":null,"abstract":"<div><div>Fluvial-delta plain complex links land, fresh water, and marine habitats and acts as a springboard during terrestrialization of both plants and animals. Its geological records or related paleoecology study, during mid to late Paleozoic, however, are scarce. In this study, we reconstruct the paleoenvironmental and paleoecological framework of a Middle Devonian (c. 387 Ma) fluvial-delta plain complex from Wuding, eastern Yunnan, South China for the first time, using a combined approach of sedimentology, geochemistry, and palaeontology. Eight lithofacies of fluvial-delta plain are recognized from the Haikou Formation. The lower part of the Haikou Formation deposited in a meandering fluvial environment. While the middle-upper part of the Haikou Formation is interpreted as a brackish-fresh water setting (i.e., delta plain-swamp) based on facies analysis, stable isotope composition (δ¹⁸O, δ¹³C) of biogenic (ostracods) and authigenic carbonates, as well as paleosalinity proxies (Sr/Ba). A synthetic biota with a variety of fossil organisms, including ostracods (29 species belonging to 7 superfamilies), charophytes (1 species), chondrichthyans and antiarch fishes (at least 2 taxa), gastropods (1 taxa), bivalves, and spores (20 species belonging to 19 genera) have been recognized and identified in the delta plain-swamp facies. Ostracods are categorized into three distinct assemblages. Assemblage 1 (Leperditicope-Palaeocope assemblage) and Assemblage 3 (Paraparchitoidean assemblage) displaying high diversity and abundance, and characterize a brackish lower delta plain and a delta plain-swamp environment, respectively. Whilst the Assemblage 2 (Leperditioidean assemblage) has relatively low diversity and inhabited in fresh water, probably an upper delta plain setting. Leperdiditioideans are pioneers colonized fluvial-delta plain setting and might be the earliest fresh water ostracods. Additionally, a special fresh water species of Cypridoidea, <em>Carbonita</em> sp., which has never been reported prior to the Carboniferous Period, is discovered in the Haikou Formation. Abundant rhizomes of vascular land plants, as well as vertically arranged traces fossils (i.e., <em>Scoyenia beerboweri</em>) are observed from the flood plain facies, representing development of belowground soil ecosystem. The biota, especially those of the ostracods and charophytes, comprise a complex ecosystem spanning the marginal marine to terrestrial settings allowing a well-structured reconstruction of the eco-pyramid of brackish-fresh water ecosystem during the Middle Devonian. The results shed light on the co-evolution of the environment and organisms in the Devonian non-marine system.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"270 ","pages":"Article 105223"},"PeriodicalIF":10.0,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144665038","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 dataset and review of empirical estimation relationships for landslide runout distances","authors":"Weibing Gong ,&nbsp;Guangshuai Wang ,&nbsp;Lin Li ,&nbsp;Boneng Chen","doi":"10.1016/j.earscirev.2025.105225","DOIUrl":"10.1016/j.earscirev.2025.105225","url":null,"abstract":"<div><div>Estimating landslide runout distances is crucial for assessing their potential impacts on surrounding infrastructure and communities. By comparing estimated runout distances with the proximity of landslides to vulnerable sites, the likelihood of landslide impact can be assessed, and the volume of debris that may reach such locations can be indirectly quantified. This paper presents a comprehensive review of 28 empirical relationships developed to estimate landslide runout distances associated with various triggering factors, including earthquakes, rainfall, and other factors, while also accounting for different material types such as soil, rock, and soil-rock mixtures. The relationships are analyzed in terms of equation formats, adopted parameters, and the number of parameters involved, identifying volume and height as the most frequently used variables and mixed equation formats (e.g., logarithmic and linear combinations) as the most common. Existing definitions of runout distance are reviewed, and this study adopts the definition as the horizontal distance between the upper point of the landslide source and the lowest point of deposition, chosen for its clarity and ease of measurement from mapped landslide inventories. To validate the summarized relationships, a dataset comprising 22,456 landslides was established. The analysis revealed low <em>R</em>² values for many existing empirical relationships, highlighting the necessity for developing improved empirical relationships. This study develops new empirical estimation relationships tailored to different triggering factors and material types, enhancing estimation accuracy of landslide runout distances. The finalized empirical relationships are offered and aim to serve as practical tools for the rapid estimation of landslide runout distances, thereby supporting effective disaster response and mitigation strategies.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"270 ","pages":"Article 105225"},"PeriodicalIF":10.8,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144664994","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":"Measures of prehistoric terrestrial net ecosystem productivity and carbon sink function","authors":"Chris Mays ,&nbsp;Richard V. Tyson ,&nbsp;Michael T. Hren","doi":"10.1016/j.earscirev.2025.105222","DOIUrl":"10.1016/j.earscirev.2025.105222","url":null,"abstract":"<div><div>Indicators of past biological productivity, or ‘palaeoproductivity proxies’, offer ways to indirectly measure key aspects of Earth's deep-time ecosystem and carbon cycle functioning. Given that plants have been the principal primary producers on land for hundreds of millions of years, the abundances of fossil plants in the rock record can indicate past ‘net terrestrial ecosystem productivity’ (NTEP). This is the net carbon storage or release by a terrestrial ecosystem, and a measure of whether an ecosystem is a carbon sink or source. When applied on a global scale, NTEP represents a major component of Earth's carbon cycle. Moreover, since plants are particularly sensitive to rapid climatic events, measuring NTEP with fossil plants should indicate how land carbon sinks have been impacted by these climatic changes. Herein, we compare and contrast three potential proxies of NTEP changes in deep time: total organic carbon (TOC), terrestrial organic microfossil concentrations (<span><math><msub><mi>c</mi><mi>t</mi></msub></math></span>) and terrestrial organic carbon (TrOC). However, the preservation pathways of terrestrial organic microfossils (hence, <span><math><msub><mi>c</mi><mi>t</mi></msub></math></span> and TrOC) are complex and poorly understood. In this review, we have: 1, adapted and applied a framework of modern net ecosystem productivity (NEP) to prehistoric settings by incorporating post-burial effects; 2, summarized the factors that influence the preservation and accumulation rates of land-derived organic carbon in the fossil record; and 3, explored the conditions under which <span><math><msub><mi>c</mi><mi>t</mi></msub></math></span> and TrOC may provide valid estimates of prehistoric NTEP. Given their specificity, we conclude that the fossil-based metrics (<span><math><msub><mi>c</mi><mi>t</mi></msub></math></span> and TrOC) hold greater potential than TOC as proxies of NTEP. Moreover, <span><math><msub><mi>c</mi><mi>t</mi></msub></math></span> and TrOC can be readily applied to the rock record to estimate the relative changes of past NTEP, if several key parameters are standardized between samples: lithofacies, depositional environment, sample thickness (as a surrogate for accumulation time), burial history, basin type and palaeolatitude. In practice, these can be addressed by targeting similar facies within the same basin over relatively short stratigraphic intervals. Moreover, the most precise fossil count techniques should be utilised to minimize data collection error. While these proxies can provide valid metrics of NTEP changes, they are not yet capable of providing absolute burial rates of terrestrial carbon. However, we produce a roadmap towards refined proxies of absolute deep-time NTEP, which would constrain biogeochemical models since the emergence of large land plants &gt;360 million years ago.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"270 ","pages":"Article 105222"},"PeriodicalIF":10.8,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144663104","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":"Corrigendum to “First comparison of subsidence/uplift rates between Copernicus European Ground Motion Service data and long-term MIS 5.5 geological record in Mediterranean regions” [Earth-Science Reviews, Volume 265, (2025), 105132]","authors":"Giovanni Luca Cardello ,&nbsp;Giovanni Barreca ,&nbsp;Carmelo Monaco ,&nbsp;Marcello de Michele ,&nbsp;Fabrizio Antonioli","doi":"10.1016/j.earscirev.2025.105212","DOIUrl":"10.1016/j.earscirev.2025.105212","url":null,"abstract":"","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"270 ","pages":"Article 105212"},"PeriodicalIF":10.0,"publicationDate":"2025-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145044493","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":"Gaseous hydrocarbons cracking in shale: Mechanism, impact and resource significance","authors":"Bin Cheng ,&nbsp;Shida Li ,&nbsp;Jianbing Xu ,&nbsp;Zewen Liao","doi":"10.1016/j.earscirev.2025.105211","DOIUrl":"10.1016/j.earscirev.2025.105211","url":null,"abstract":"<div><div>Gaseous hydrocarbons (C₁ − C₅) are the primary components of shale gas. Their thermal degradation significantly impacts various aspects of shale gas reservoirs, including gaseous hydrocarbons composition and their carbon and hydrogen isotopes fractionation, H₂ generation, reservoir overpressure, mineral dissolution and brittle mineral formation, changes in reservoir properties and storage space, as well as the formation and identification of resource sweet spots. This study reviews the experimental simulations of gaseous hydrocarbon cracking and the geochemical research on major global shale gas reservoirs conducted over the past few decades. In shale gas reservoirs, C₅H₁₂, C₄H₁₀, C₃H₈, C₂H₆ and CH₄ initiate cracking at Ro values of approximately 1.0 %, 1.0 %, 1.3 %, 1.5 %, and 2.0 %, respectively, with main cracking stages occurring at Ro ranges of 1.7–2.4 %, 1.7–2.8 %, 1.8–3.2 %, 1.8–3.6 %, and 3.0–4.0 %. This cracking produces more gaseous molecules, significantly contributing to overpressure and H₂ in high-overmature reservoirs. Wet gas cracking contributes carbon isotope rollover but CH₄ cracking causes both carbon and hydrogen isotope reversals in shale gas. As CH₄ cracking onset marks peak gas generation of shale, carbon isotope reversal serves as a key sweet-spot indicator. Furthermore, hydrous pyrolysis of gaseous hydrocarbons generates formic and acetic acids that enhance porosity and permeability by dissolving carbonate and feldspar minerals. Concurrent silica precipitation during feldspar dissolution promotes quartz formation, improving reservoir fracturability. This study advances our understandings of the formation, evolution and associated geological and geochemical anomalies of shale gas reservoirs, which holds significant implications for the exploration and exploitation of shale gas resources.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"270 ","pages":"Article 105211"},"PeriodicalIF":10.8,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144579702","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":"Diagenesis of hydrocarbon-seep carbonates: Common patterns, divergent pathways and conceptual pitfalls","authors":"M. Jakubowicz ,&nbsp;S.A. Akam ,&nbsp;C. Argentino ,&nbsp;K. Hryniewicz ,&nbsp;G. Panieri ,&nbsp;S. Kiel ,&nbsp;Z. Belka","doi":"10.1016/j.earscirev.2025.105210","DOIUrl":"10.1016/j.earscirev.2025.105210","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Authigenic carbonates formed at marine hydrocarbon seeps are an important component of carbon cycling at continental margins. Ancient hydrocarbon-seep deposits serve as archives of the evolution of chemosynthesis-based ecosystems, past pore-water chemistry, and the tectonic architecture and geological history of their host sedimentary basins. However, while modern and ancient seep deposits share many similarities, they also show notable differences in their petrological and geochemical characteristics. The insufficient understanding of the origin of these differences limits our ability to address fundamental questions about the palaeoecology of seep-specialised communities, the geological evolution of seep-hosting plate margins, and secular changes in the composition of the seeping fluids and/or seawater. Here, we critically evaluate the carbon, oxygen and strontium isotope signatures, as well as selected minor and trace element systematics of ancient seep carbonates. We identify distinctive, recurring patterns and discuss them in the context of current understanding of the controls on carbonate authigenesis and alteration in marine pore waters. The precipitation of seep carbonates mostly from sediment pore waters at the transition between the sulphate reduction and methanogenic zones favours the preservation of primary textural and geochemical characteristics. However, in this anoxic, spatially and temporarily complex setting, the concentrations of many minor and trace elements, including the refractory lithophile elements, are subject to increased mobility during fluid-rock interactions, mineral transformations and organic matter decomposition. This mobility complicates their traditional use as indicators of post-depositional alteration, laboratory artefacts, or original mineralogies. The high concentrations of strontium with non-marine &lt;sup&gt;87&lt;/sup&gt;Sr/&lt;sup&gt;86&lt;/sup&gt;Sr ratios that may be introduced with the seeping fluids offer insights into the fluid sources and basement characteristics, but also limit the utility of Sr isotope stratigraphy for dating seep deposits. A negative correlation between the δ&lt;sup&gt;13&lt;/sup&gt;C and δ&lt;sup&gt;18&lt;/sup&gt;O values, commonly observed in microcrystalline phases, most likely reflects the continuous cementation of seep carbonates during burial in the methanogenic zone. This process is driven by methanogenesis-associated aluminosilicate weathering, releasing &lt;sup&gt;13&lt;/sup&gt;C-enriched and &lt;sup&gt;18&lt;/sup&gt;O-depleted fluids. Another common pattern, the narrow clustering of strongly negative δ&lt;sup&gt;18&lt;/sup&gt;O signals, appears to record selective δ&lt;sup&gt;18&lt;/sup&gt;O resetting during fluid-dominated post-depositional alteration. The observed increased δ&lt;sup&gt;13&lt;/sup&gt;C values of seep carbonates during parts of the Paleozoic and Mesozoic may be associated with the secular changes in the dissolved inorganic carbon concentration of seawater, while the role of other controls remains unclear. Our work provides a timely synthesis of th","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"270 ","pages":"Article 105210"},"PeriodicalIF":10.8,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144605438","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":"Avalanche susceptibility factors, trends, techniques, and practices in Indian Himalaya: A review","authors":"Kirti Thakur ,&nbsp;Harish Kumar ,&nbsp;Snehmani","doi":"10.1016/j.earscirev.2025.105207","DOIUrl":"10.1016/j.earscirev.2025.105207","url":null,"abstract":"<div><div>Avalanche susceptibility mapping is the primary step for avalanche investigation, safer planning, and future development activities. Therefore, investigation of the terrain, snowpack and meteorological characteristics are crucial for the avalanche susceptibility assessment. In this paper, various parameters responsible for different types of avalanche occurrence and their significance are discussed for Indian Himalayas. This paper reviews 373 research papers published between 2013 and 2024 to gain insight into the current trends, techniques, and practices used in avalanche susceptibility mapping. After reviewing the related literature, it has been observed that no universally acceptable standard parameters or model exist that can describe all types of avalanche activities adequately. Secondly, based on expert knowledge about all snowpack and meteorological parameters, only twelve parameters are mainly used in the snow avalanche related prediction model. Hence, there is a need to explore the combination of other parameters and their impact to improve the model's accuracy. It highlights important aspects and provides a broader perspective on avalanche mapping that may be useful for practitioners worldwide, while also serving as a valuable database for researchers in this field, particularly those working in the Himalayan region. Finally, the vital issues arising in this research field that need to be addressed by the researchers are discussed. It is expected that the accuracy and applicability of models could be greatly improved, by incorporating big data geo-analytics techniques, utilizing deep learning methods, and spatiotemporal modelling.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"269 ","pages":"Article 105207"},"PeriodicalIF":10.8,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144522409","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":"Recent advances and future research directions in deep learning as applied to geochemical mapping","authors":"Ying Xu ,&nbsp;Renguang Zuo ,&nbsp;Zhiyi Chen ,&nbsp;Zixian Shi ,&nbsp;Oliver P. Kreuzer","doi":"10.1016/j.earscirev.2025.105209","DOIUrl":"10.1016/j.earscirev.2025.105209","url":null,"abstract":"<div><div>Geochemical survey data are a key tool for identifying geochemical patterns and anomalies relevant to mineral exploration. In the past decade, artificial intelligence (AI) has been widely applied in geochemical data mining to compensate for the shortcomings of traditional methods. Here, we first reviewed the applications of five popular deep learning algorithms (DLAs) adopted in the past six years (i.e., from 2019 to 2025), namely deep belief network, recurrent neural network, convolutional neural network, autoencoder, and generative adversarial network. We then examined recent state-of-the-art applications of DLAs in geochemical spatial pattern recognition, which served to highlight their advantages over the five popular DLAs previously discussed. Subsequently, we flagged three critical challenges in DLA-based geochemical mapping: (i) inadequate representation of complex spatial heterogeneity patterns of geochemical survey data, (ii) development of innovative models to overcome the limitations imposed by insufficient training samples, and (iii) systematic integration of geological constraints to enhance model accuracy and interpretability. To address these limitations, we proposed two promising, novel architectures: (i) graph self-supervised learning and (ii) graph reinforcement learning (GRL). Graph self-supervised learning represents geochemical data as graph structures, using self-supervised techniques to address training data limitations. Furthermore, the model uses Transformer for modeling global spatial relationships and embeds knowledge nodes for ensuring geological consistency during model training. Like the above, GRL employs graph representations of geochemical data, also combining graph convolutional networks within a reinforcement learning system. The key advancement of GRL involves the creation of reward functions that incorporate geological rules, thereby linking expert knowledge and DLAs through dynamic environment feedback. A case study is presented to demonstrate the effectiveness of these approaches and highlights the potential for integrating advanced methodologies to enhance the accuracy and reliability of geochemical anomaly identification in complex geological settings.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"270 ","pages":"Article 105209"},"PeriodicalIF":10.8,"publicationDate":"2025-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144563618","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":"Meso–Cenozoic exhumation history of Northeast Asia and its connections with tectonic and climatic factors","authors":"Hongtao Wang ,&nbsp;Shichao Li ,&nbsp;Rong Yang ,&nbsp;Xiaopeng Yang ,&nbsp;Fangbin Liu ,&nbsp;Zheren Zhao","doi":"10.1016/j.earscirev.2025.105208","DOIUrl":"10.1016/j.earscirev.2025.105208","url":null,"abstract":"<div><div>Northeast Asia, a prominent basin-and-range system during the Mesozoic–Cenozoic, provides a unique context for studying how deep Earth processes influence surface landscape evolution. However, the comprehensive exhumation history and its connections to tectonic and climatic factors remain poorly understood. In this study, we analyze spatiotemporal variations in exhumation rates across Northeast Asia by compiling and inverting a dataset of apatite and zircon fission track and (U-Th)/He ages, alongside crustal deformation and paleoclimate data. Our results reveal differential rapid exhumation from the Late Jurassic to Early Cretaceous (150–110 Ma), primarily driven by the closure of the Mongol–Okhotsk Ocean and subduction of the paleo-Pacific plates, further enhanced by increased precipitation. From 110 to 90 Ma, exhumation rates progressively decreased from the continental margin to the interior (∼0.69 km/Myr to ∼0.20 km/Myr), influenced mainly by compressional deformation. During the late Cretaceous to Paleocene (90–60 Ma), the Northeast Asian mountains underwent widespread rapid exhumation, with a peak rate of 0.85 km/Myr. However, toward the end of this period, exhumation slowed due to the diminished tectonic forces from paleo-Pacific plates subduction and arid climatic conditions. Cenozoic localized exhumation was driven primarily by mid-ocean ridge and Pacific Plate subduction, with minimal climatic influence. The present-day basin-and-range landscape of Northeast Asia is the cumulative outcome of tectonic and climatic forcing since the Mesozoic.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"269 ","pages":"Article 105208"},"PeriodicalIF":10.8,"publicationDate":"2025-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144535796","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 deep conductive layer in the Icelandic crust","authors":"Knútur Árnason ,&nbsp;Benoit Gibert ,&nbsp;Claire Bouligand ,&nbsp;Arnar Már Vilhjálmsson","doi":"10.1016/j.earscirev.2025.105198","DOIUrl":"10.1016/j.earscirev.2025.105198","url":null,"abstract":"<div><div>Early MagnetoTelluric (MT) resistivity soundings in Iceland revealed a Deep Conductive Layer (DCL), a layer with anomalously high conductivity, at the depth of 5-20 km (upper seismic layer 3) in the crust under most of the country. When first observed in the 1970s, the DCL was interpreted as partial melt below a thin and hot crust. Later seismic and gravity studies have showed that the crust is 20–40 km thick, dense and relatively cold. The DCL is thus an intra-crustal layer below the brittle/ductile transition and does not correlate with any currently known seismic feature. In this paper we try to narrow down the possible origin(s) and nature of the enigmatic DCL and how its presence can be understood in the framework of the thick and cold crustal model. We review existing electrical conductivity data from early MT measurements done in the 1970s and 1980s and from recent surveys mostly done in the context of geothermal exploration. The DCL domes up beneath active central volcanoes and high temperature geothermal areas. It is found to be electrically anisotropic, being more conductive in the spreading direction than in the tectonic/fracture direction. We review several possible conduction mechanisms that could explain the high conductivity in the light of recent experimental work on electrical conductivity of minerals and rocks and discuss the possible prevailing conduction mechanisms in the light of existing geophysical and petrological observations in Iceland. These investigations show that seismic and electrical surveys are both compatible with the presence of melt in the DCL in the volcanic plumbing system associated to volcanoes. Outside active volcanoes, seismic properties of the DCL, inferred from local tomography, are not compatible with the presence of melt or even aqueous fluid in the DCL but confirm thick, cold and fluid-free lower crust, leaving only solid-state conduction as a viable conduction mechanism. Review of laboratory measurements on various type of minerals leads to the conclusion that the presence of Fe<img>Ti oxides or hydrated minerals, such as amphibole, could explain the DCL. In Eyjafjörður, North Iceland, the only low-temperature geothermal area studied using MT to date, the DCL locally domes up to shallow depths under the geothermal area. This suggests possible correlation between low-temperature geothermal activity and relatively shallow DCL. Detailed mapping of the DCL might therefore be an important tool in prospection for low-temperature geothermal resources.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"270 ","pages":"Article 105198"},"PeriodicalIF":10.0,"publicationDate":"2025-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144503855","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}