Earth-Science Reviews最新文献

{"title":"Seismic hazard and shifting channels: Exploring coseismic river response","authors":"Erin McEwan , Timothy Stahl , Rob Langridge , Tim Davies , Andrew Howell , Matthew Wilson","doi":"10.1016/j.earscirev.2025.105042","DOIUrl":"10.1016/j.earscirev.2025.105042","url":null,"abstract":"<div><div>Large earthquakes can trigger cascading flood hazards that can influence societal risk and loss; however, the mechanisms driving coseismic river response (CRR) in seismogenic regions have not been fully characterized. This review synthesizes data from fifty-two global cases of CRR where surface deformation affected rivers and identifies the key physical and environmental parameters that control riverine flood hazard in earthquakes. We identify four primary CRR classes, ranging from channel-confined ponding to overbank flooding and avulsion, wherein a river shifts into an enduring new course within the floodplain. CRR susceptibility governs the likelihood, spatial extent, and longevity of CRR, and links back to the characteristics of the surface deformation, river planform, and host environmental setting. Dip-slip fault ruptures, with a large vertical separation at the surface capable of damming river channels, are the primary driver of CRR. Multi-meter dip-slip offsets are also linked to fault-block tilting, which reduce or reverse the gradients of overlying channels. These tilted fault blocks can induce coseismic flooding or avulsion away from the principal fault, with cases documented up c. 10 km upstream from the fault-river intersection. Lateral offsets can amplify or modulate CRR but are generally less effective than vertical offsets at causing them. Two-thirds of CRR cases occurred in single-thread rivers, the majority of which are meandering systems occupying intermontane or lowland basins. Liquefaction-prone substrates in these floodplains exacerbate CRR impacts through ground deformation that disrupts river channel profiles and the local water table. Overbank flooding, lake formation, and prolonged surface flooding are common outcomes near meandering channels and may occur away from the principal fault. Confined braided rivers with high width-to-depth ratios are more resistant to overbank flow and avulsion. In unconfined settings, erodible substrates, and low lateral bank stability amplify the potential for channel scour and rapid avulsion. Braided floodplains often host dense networks of paleochannels within their floodplain, and in any environment, paleochannels enhance the potential for, and geographic extent of flooding and avulsion. High discharge conditions elevate the potential for overbank flow and avulsion, and the hazard posed by CRR may be higher in regions where the climate is perennially or seasonally wet. The risk posed by CRR during earthquakes is heightened in areas where population expansion and land reclamation in flood and liquefaction-prone zones is commonplace. A method to assess CRR risk in advance is required, and a probabilistic framework incorporating uncertainties in fault behaviour, recurrence intervals, and flood-rating curves may offer a way to evaluate absolute hazard in areas where faults and rivers intersect. Site-specific hydrodynamic modelling can further quantify potential changes in flood pat","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 105042"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136870","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 deterioration and collapse of late Permian marine ecosystems and the end-Permian mass extinction: A global view","authors":"Weihong He ,&nbsp;G.R. Shi ,&nbsp;Kexin Zhang ,&nbsp;N. Suzuki ,&nbsp;Han Wang ,&nbsp;Fangfang Yang ,&nbsp;Yifan Xiao ,&nbsp;Tinglu Yang ,&nbsp;Yafei Huang ,&nbsp;Chen Wu ,&nbsp;Ke Jiang","doi":"10.1016/j.earscirev.2024.104971","DOIUrl":"10.1016/j.earscirev.2024.104971","url":null,"abstract":"<div><div>An ever-expanding body of studies has revealed that the evolution of late Permian ecosystems was very complex and possibly involved some yet under-studied ‘early warning signals’ prior to the end-Permian mass extinction. However, the evidence in support of pre-extinction ‘warning signals’ is still limited. In a global review, this paper examined the timing for the initial and peak stages of the late Permian (including the Permian-Triassic boundary interval) biodiversity crisis across different palaeogeographic (palaeobathymetric) settings ranging from pelagic, deep-water basin/deep shelf, through moderately deep-water slope, and to shallow-water carbonate, reef and shallow shelf settings. Based on detailed correlations of globally significant Permian-Triassic sections (20 key sections reviewed) and key stratigraphic boundaries using bio-, chrono- and chemo-stratigraphy, this paper evaluated, summarized and compared the timing and pacing of the environmental and ecosystem deterioration processes in each and among the different palaeogeographic settings and between planktons (mainly radiolarians) and benthos (represented mainly by brachiopods and benthic foraminifers) in deep and moderately deep marine waters. Additionally, where data available we also reviewed the temporal evolution of redox conditions for 17 Permian-Triassic key sections in an attempt to ascertain if there were any notable temporal correlations between these two seemingly separate but potentially mechanistically linked processes. Finally, we also discussed the possible cause-effect and mutually amplifying relationships among volcanism, warming, dynamics of the oxygen minimum zone (OMZ), and the deterioration and final collapse of both marine and terrestrial ecosystems in the late Permian in the lead up to the end-Permian mass extinction.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 104971"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143136874","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":"Molecular mechanisms and biomineralization processes of ferromanganese nodule formation: Insights its effect on nutrient imbalance and heavy metal immobilization in native soil profiles","authors":"Danish Ali ,&nbsp;Suprokash Koner ,&nbsp;Ashiq Hussain ,&nbsp;Bing-Mu Hsu","doi":"10.1016/j.earscirev.2024.105029","DOIUrl":"10.1016/j.earscirev.2024.105029","url":null,"abstract":"<div><div>Ferromanganese nodules (FMNs), simultaneously termed as manganese nodules, are metallic concretions typically found in the B horizon of iron and manganese-rich soils. These nodules are primarily formed through the biomineralization process driven by favorable redox reactions and microbial activity. The formation of FMNs in the soil is governed by complex geochemical interactions and influenced by both biotic and abiotic factors, such as temperature, pH, organic matter, redox potential (Eh), wet/dry cycles, and nucleation sites. FMNs typically vary in size, ranging from a few microns to several centimeters, and exhibit diverse shapes, from spherical to irregular. These nodules play a crucial role in nutrient cycling and the adsorption of heavy metals, including phosphorus, lead, copper, zinc, cobalt, and nickel, thereby improving soil quality and preventing metal leaching into aquatic environments. The ion exchange during redox reactions, complexation, occlusion, and adsorption are the key mechanisms through which heavy metals can become immobilized in soil FMNs. The formation of FMNs involves Mn-oxidizing bacteria, such as <em>Bacillus, Pedomicrobium, Erythrobacter, Pseudomonas putida, Geobacter,</em> and <em>Leptothrix discophora,</em> which use specific functional genes such as <em>mnxG, moxA, mopA, CumA, ombB, omaB, OmcB,</em> and <em>mofA</em> to facilitate manganese oxidation. This process reacts with geological material, resulting in the precipitation of metal leachates and the development of metal oxide coatings that serve as nucleation sites for FMNs. Such microbial activities are not only essential for FMNs formation but also for trapping heavy metals in soil, highlighting their importance in soil biogeochemical cycling and ecological functions. However, further research is needed to unravel the complex biogeochemical interactions that influence FMNs growth and composition, as well as to understand the stabilization and release dynamics of nutrients and heavy metals, and the roles of microbial communities and functional genes involved in these processes, particularly in relation to soil fertility and plant nutrition.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"261 ","pages":"Article 105029"},"PeriodicalIF":10.8,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142874281","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 systematic review of the hydrogeomorphological impacts of large dams in Africa","authors":"Sofie Annys ,&nbsp;Amaury Frankl","doi":"10.1016/j.earscirev.2025.105048","DOIUrl":"10.1016/j.earscirev.2025.105048","url":null,"abstract":"<div><div>Large dams exert significant impacts on the hydrology and geomorphology of the rivers they impound. Although there is a renewed interest in large dams in Africa to support sustainable development in the face of a changing climate, no systematic review of their hydrogeomorphological impacts exists at continental scale. In this review, we compiled a geospatial dataset of 1047 large dams from different data sources (jointly storing up to 948.7 km³; equal to 29 % of the continent's average annual discharge), and systematically investigated the impact these dams have on water and sediment regimes, river and coastal geomorphology. Our findings reveal a consistent augmentation in low flows and a pronounced reduction in high flows (resulting in an average 35 % reduction in the coefficient of variation of monthly discharges), and often, a decrease in average river flows. The total sediment retention by these dams was estimated at 459.6 Mt. yr^-1, with fluxes towards the Mediterranean Sea being particularly reduced by 197.6 Mt. yr^-1. Although trends in altered flow regimes and trapping efficiencies (average of 85.5 %) display broad consistency across the continent, the associated geomorphological changes frequently exhibit localized variations. Common alterations encompass riverbed incision and a narrowing of the active riverbed. Coastal erosion and the permanent opening or closing of estuaries are also recurrently observed. This research significantly advances our understanding of the water infrastructure and its potential challenges for sustainable water and sediment management in the context of a changing climate and ever-high erosion rates.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"262 ","pages":"Article 105048"},"PeriodicalIF":10.8,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143180624","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":"Tectono-magmatic controls on porphyry Cu endowment in the Carboniferous Dananhu Arc, Central Asian Orogenic Belt: A review","authors":"Yi-Hao Liu ,&nbsp;Chun-Ji Xue ,&nbsp;Yun Zhao ,&nbsp;Xiao-Bo Zhao ,&nbsp;Reimar Seltmann ,&nbsp;Matthew J. Brzozowski ,&nbsp;David T.A. Symons","doi":"10.1016/j.earscirev.2025.105047","DOIUrl":"10.1016/j.earscirev.2025.105047","url":null,"abstract":"<div><div>Situated in the southwestern margin of the Central Asian Orogenic Belt, the Dananhu Arc is a prominent porphyry Cu belt in NW China. The Carboniferous granitoids that host two giant to large and several medium to small porphyry Cu deposits are concentrated in the middle segment of the arc. In contrast, coeval granitoids in the adjacent western and eastern segments are barren. The key factors controlling porphyry fertility and diversity in this arc have not been well constrained. The geochemical and Sr–Nd–Hf–O isotopic compositions of Carboniferous fertile and barren magmas exhibit systematic variations from west to east along the 600 km-long Dananhu Arc. Fertile granitoids have adakitic affinities, with high Sr/Y ratios, Mg#, and oxygen fugacity (ΔFMQ = +2.53 ± 0.52), and depleted Sr–Nd–Hf–O isotopic compositions. The barren alkaline granitoids in the western segment are characterized by enrichments in large ion lithophile elements, low Mg# and oxygen fugacity (ΔFMQ = +0.31 ± 0.11), and evolved Sr–Nd–Hf–O isotope compositions. The barren calc-alkaline granitoids in the eastern segment have low Sr/Y ratios, moderate Mg# and oxygen fugacity (ΔFMQ = +1.65 ± 0.50), and depleted Sr–Nd–Hf–O isotopic compositions. The fertile adakitic granitoids originated from partial melting of a flat-subducted oceanic slab accompanied by crustal thickening. The barren alkaline granitoids were derived from anatexis of accretionary complexes triggered by slab rollback accompanied by magma migration and crustal thinning. The barren calc-alkaline granitoids were derived from partial melting of the mantle wedge in a normal subduction setting. Taken together, we suggest that distinct tectonic settings generated the heterogeneous distribution of porphyry Cu deposits throughout the Dananhu Arc by controlling the nature of the magma that was generated.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"262 ","pages":"Article 105047"},"PeriodicalIF":10.8,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143180622","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":"Tectonic evolution of the eastern Central Asian Orogenic Belt during the Carboniferous–Permian","authors":"Tong Zhou ,&nbsp;Yongjiang Liu ,&nbsp;Qingbin Guan ,&nbsp;Boran Liu ,&nbsp;Wenjiao Xiao ,&nbsp;Sanzhong Li ,&nbsp;Zhaoxu Chen ,&nbsp;A. Yu Peskov","doi":"10.1016/j.earscirev.2025.105046","DOIUrl":"10.1016/j.earscirev.2025.105046","url":null,"abstract":"<div><div>The eastern Central Asian Orogenic Belt (CAOB) is an interactive area of multiple tectonic regimes. In the past decades, researchers have conducted extensive studies in the eastern CAOB over the past decades and reported plenty of new data. However, there are still many open questions and arguments dealing with the correlation and tectonic affinity of different blocks with Precambrian crystalline basements, the subduction tectonic processes, and the initiation time of the oceans surrounding the blocks at the eastern CAOB. In this study, we provide a detailed review of the tectonic evolution of the Precambrian blocks in the Eastern Mongolia, NE China, and Far East Russia and provide a regional comparison and correlation of the different tectonic units in the region, initial subduction of Mongolia–Okhotsk Ocean and Pathalassa Ocean, and set up a tectonic evolution model from Carboniferous to Permian. In the late Early Paleozoic, the Ereendavaa Block in Eastern Mongolia and the Erguna and Jiamusi Blocks in NE China, as well as the Mamyn and Bureya Blocks in the Far East Russia, respectively formed the Ereendavaa–Erguna–Mamyn Block chain (EEMB) and Bureya–Jiamusi–Khanka Block chain (BJKB) were formed and probably connected and constructed a long united block chain. Combined with the geochronological and geochemical data of the late Paleozoic magmatic rocks from these tectonic units, we suggest that the southeastward subduction of the Mongolia–Okhotsk Ocean along the northwestern margin of the EEMB was initiated in the Late Carboniferous, then the westward subduction of the Panthalassa Ocean along the eastern margin of the BJKB was subsequently initiated in the Late Carboniferous, indicating that the initial subduction around outside of which migrated from west to east. With the continuous subduction of the Mongolia–Okhotsk Ocean and Panthalassa Ocean, the EEMB–BJKB block chain underwent further bending, forming a southward–opened curve and constituted the NE China Orocline.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"262 ","pages":"Article 105046"},"PeriodicalIF":10.8,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181198","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":"Thermally driven organic-inorganic interactions in sedimentary basins: A review from source rocks to reservoirs","authors":"Guanghui Yuan ,&nbsp;Yingchang Cao ,&nbsp;Zhijun Jin ,&nbsp;Hans-Martin Schulz ,&nbsp;Zihao Jin ,&nbsp;Rui Fang ,&nbsp;Xiaoyang Zhao ,&nbsp;Keyu Liu ,&nbsp;Jixuan Wang","doi":"10.1016/j.earscirev.2025.105043","DOIUrl":"10.1016/j.earscirev.2025.105043","url":null,"abstract":"<div><div>Organic-inorganic interactions, ubiquitous in sedimentary basins, critically influence the genesis and evolution of petroleum and natural gases. These processes also modify the inorganic rock matrix as well as cause the formation of secondary pores. This review synthesizes evidences from thermal experiments and geological case studies to examine the genesis, evolution pathways and significance of thermally driven interactions in kerogen-rich source rocks and hydrocarbon reservoirs.</div><div>Several mechanisms have been proposed to elucidate the initiation of these interactions, including the carbonium-ion mechanisms, stepwise-oxidation of hydrocarbon by water in the presence of ferric iron-bearing minerals, Fischer-Tropsch-type (FTT) synthetic reactions, and free radical mechanisms. Recent observations of water microdroplets formed near oil-water interfaces at elevated temperatures suggest a potential non-catalytic free radical mechanism underlying the oil-water interactions in hot hydrocarbon reservoirs. In source rocks, clay minerals (smectite, S/I, and illite), calcite, and Fe/Mn-containing metal minerals significantly impact kerogen degradation through their Brønsted and Lewis acid sites, M²⁺-O surface groups, and partially filled d orbitals. In reservoir settings, kaolinite, illite, feldspar and carbonate minerals primarily influence hydrocarbon degradation. Water, present throughout these environments, facilitates the generation of low-molecular-weight hydrocarbons, organic acids, and CO₂ through external hydrogen and oxygen contribution. It also modulates minerals effects on the thermal evolution of kerogen, crude oil, and natural gases. Acids produced during kerogen maturation promote mineral alterations, including smectite illitization, feldspar alteration and calcite recrystallization. These processes, sustained by continuous acid generation from hydrocarbon oxidation, contribute to ongoing mineral transformation and secondary porosity development in deeply buried reservoirs, significantly affecting reservoir quality. At elevated temperatures, extensive organic-inorganic interactions, facilitated by inorganic-derived hydrogen and oxygen, influence deep hydrocarbon potential, natural gas isotopic composition, and the depth limit of liquid hydrocarbon preservation.</div><div>Despite these advances, uncertainties remain regarding the differential impacts of various inorganic species on organic reactions. Future research should focus on elucidating the detailed evolution pathways and associated reactions of thermally altered rocks with diverse organic-inorganic combinations, particularly in fine-grained shales and ultra-deep hydrocarbon reservoirs. Additionally, investigating the quantitative kinetics of coupled mineral alteration and organic reactions would address crucial knowledge gaps in our understanding of these processes.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"262 ","pages":"Article 105043"},"PeriodicalIF":10.8,"publicationDate":"2025-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143180621","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":"Thickness of the stratigraphic record of Britain: How the fidelity of geological and fossil data is unrelated to rock quantity","authors":"James A. Craig ,&nbsp;Ralph J. Battle ,&nbsp;Yorick P. Veenma ,&nbsp;William J. McMahon ,&nbsp;Ben J. Slater ,&nbsp;Anthony P. Shillito ,&nbsp;Neil S. Davies","doi":"10.1016/j.earscirev.2025.105045","DOIUrl":"10.1016/j.earscirev.2025.105045","url":null,"abstract":"<div><div>The sedimentary-stratigraphic record is the principal repository of empirical historic evidence for evolution and deep time environments. However, the record has a temporal incompleteness and inconsistency to its extensive quantity, driven by the spatial heterogeneity of deposition and erosion. This is argued to bias intensive fossil records, with correlations apparent between fossil diversity and mapped rock area from different intervals. However, mapped rock area is a poor proxy for strata accessible for fossil studies because most is concealed. Additionally, spatially diminutive older rocks commonly sample a greater stratigraphic transect per unit exposure area than widespread younger rocks because the tectonic forces that drive recycling additionally result in tilting. We calculate observable vertical stratigraphic thickness throughout geologic history for southern Britain and show that potential sample availability increases with age, in contrast to general models of rock survivorship. Using this subsample of the sedimentary-stratigraphic record as a calibration sample for the global record, we find no correlation between available stratigraphic thickness and palaeobiodiversity, except in flat-lying strata. We demonstrate instances where the first occurrences of fossil genera appear robust because there is high availability of suitable host rock pre-dating them. Our work suggests that preservation biases induced by variability in rock quantity have been significantly overstated and that local tectonic history renders different regions as stratigraphic hotspots for specific intervals, in which intensive high-veracity fossil records have exceptional value for elucidating global trends and timing in evolutionary history. The British non-marine Palaeozoic record is highlighted as such an example, with high-fidelity palynological records of plant evolution and ichnological records of animal terrestrialization.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"262 ","pages":"Article 105045"},"PeriodicalIF":10.8,"publicationDate":"2025-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A review of 3.7 Ga stromatolites from the Isua Supracrustal Belt, West Greenland","authors":"Martin J. Van Kranendonk ,&nbsp;Allen P. Nutman ,&nbsp;Clark R.L. Friend ,&nbsp;Vickie C. Bennett","doi":"10.1016/j.earscirev.2024.105034","DOIUrl":"10.1016/j.earscirev.2024.105034","url":null,"abstract":"<div><div>This paper reviews the origin of putative stromatolites within 3.7 Ga meta-dolostones from the Isua Supracrustal Belt (Greenland) as either bona fide biogenic structures, as other (abiogenic) types of primary sedimentary structures, or as the products of structural deformation.</div><div>Regional mapping shows that primary structures are preserved locally across a range of lithology, specifically within the hinge zones of fold structures. Examples of such primary structures – bedding, cross-bedding, and edgewise conglomerate – within the fold structure that hosts the stromatolites, which have been discounted by some as the products of high strain, are here re-affirmed to be primary structures. Importantly, this demonstrates the potential of localised exceptional preservation. Critically, bedding and cross-bedding are defined by a combination of compositional variations and grain size that, together with an asymptotic geometry of the latter present an uniquely compelling case against the formation of these features through shearing and deformational tectonic forces.</div><div>The stromatolites can be discriminated from either primary sedimentary flame structures caused by sediment loading, or sand volcanoes caused by dewatering. Similarly, they can be discriminated from necking structures formed by tectonic boudinage on geometrical grounds, nor are they boudins themselves as they are asymmetrical and irregularly spaced. They are also clearly distinct from small-scale fold structures because of the repeated flat-base versus conical-top geometry of the stromatolites across four individual layers.</div><div>Instead, the putative stromatolites display characteristic features consistent with formation as biogenic structures. They occur in specific horizons that lie within a well-preserved stratigraphy, have flat bases and coniform to domical upper surfaces, display internal laminations, and are made of dolomite with REE + Y and stable isotopic values consistent with deposition in a biologically-influenced shallow sea. They are strained structures, elongated along the plunge direction of the regional synformal anticlinal fold in which they occur (i.e., the X-axis of the local strain ellipsoid). Importantly, 3-D observations show that the coniform stromatolites taper in the finite extension direction and that overlying mica-rich meta-dolomite beds lap onto the stromatolites in all dimensions.</div><div>In conclusion, the Isua stromatolites conform to known biogenic structures from throughout the geological record, both in terms of their overall setting, but also their unique geometry that is clearly distinct from any other known mechanism of formation. Their preservation is best explained by their occurrence within a fold hinge that has experienced plane strain in a small domain that escaped infiltration by H₂O-rich metamorphic fluids into siliceous meta-dolostones.</div></div>","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"262 ","pages":"Article 105034"},"PeriodicalIF":10.8,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143180623","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 intra-Mesozoic bauxite-bearing truncations of the peri-Neotethyan realm (Dinarides/Vardar Zone): A multidisciplinary approach shedding new light on the Neocimmerian event","authors":"Darko Spahić ,&nbsp;Pavle Tančić ,&nbsp;Lidja Kurešević ,&nbsp;Željko Cvetković ,&nbsp;Maja Poznanović Spahić","doi":"10.1016/j.earscirev.2025.105040","DOIUrl":"10.1016/j.earscirev.2025.105040","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Once coupled with global eustatic levels, bauxites, breccias, unconformities, and hiatuses are significant markers of compressional geodynamics. Most Balkan intra-Mesozoic bauxites, embedded within widespread Triassic carbonate parental sequences, are dominantly distributed in the tectonically exhumed broader Neotethyan realm (Dinarides &lt;em&gt;s.l.&lt;/em&gt;). The same mid-Mesozoic stratigraphic interval within the Vardar Zone contains fewer bauxites (East Vardar Zone), exposing abundant corresponding depositional truncations, with occasional nappe stacking configuration and metamorphism. This study, which initially acquired data from a large number of mid-Mesozoic unconformities, carbonate breccias, and similar age bauxites spreading across Dinarides &lt;em&gt;s.l.&lt;/em&gt;, Serbia, Bosnia and Herzegovina, Montenegro, Croatia (Inner and External Dinarides, Western and East Vardar Zone), including Hellenides in Greece, has provided valuable paleogeographic and geodynamic insights. The findings of this study, combined with the available mineralogical and geochemical data, deformation, including the resulting provenances of intra-Mesozoic bauxite deposits, have led to a complex and intriguing discussion on the tectonic origin of similar age unconformities across Dinaride-Hellenide and Vardar Zone Neotethyan regions. These Dinaride-Hellenide intra-Mesozoic unconformities, carbonate breccias, and widespread bauxites are a fascinating puzzle as no study deals with the complex and controversial processes of repeated regional-scale uplifts, erosion, and bauxite formation. The ambiguity revolves around the geodynamic origin of the Jurassic ophiolites in the first place and its connection with mid-Mesozoic Cimmerian orogenic events (Neocimmerian stage). Thus, the Triassic – Jurassic(Lower Cretaceous) Inner Dinaride Ophiolite belt is particularly interesting accounting for the absence of the latest Jurassic – earliest Cretacous stratigraphic interval. Many of the bauxite ores are produced on Middle Triassic to Jurassic parental limestones, whereby the hiatus can last until the beginning of the Upper Cretaceous.&lt;/div&gt;&lt;div&gt;The Triassic rifting and opening of “Dinaric Tethys”, which likely caused the pre-Neocimmerian Late Triassic shoulder uplift of early passive margins, continued into the Jurassic mid-oceanic spreading. The Triassic and Jurassic-aged zircon grains in bauxites, including new data extracted from the bauxite geochemical database, corroborate a volcanic parental affinity originating from exposed Jurassic volcanic rocks. The new geochemical analysis allowed the separation of ultramafic from mafic bauxite sources, whereby acidic sources are absent or well hidden within Inner Dinarides. Bauxite deposits at the southern edge of the Inner Dinaride area show an abundance of incompatible Mn, demonstrating a significant transgressional Oxfordian eustatic high-stand episode (precipitation of Mn on top of submerged paleokarst/bauxites). This, a Red Sea-type smal","PeriodicalId":11483,"journal":{"name":"Earth-Science Reviews","volume":"262 ","pages":"Article 105040"},"PeriodicalIF":10.8,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143181195","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}