Precambrian Research最新文献

{"title":"First evidence of tubular fossils from the Anti-Atlas: Insights into the paleogeography of Late Ediacaran tubular fossils and the Ediacaran–Cambrian boundary in the Anti-Atlas","authors":"El Hassane Beraaouz,&nbsp;Jamal El Kabouri","doi":"10.1016/j.precamres.2025.107962","DOIUrl":"10.1016/j.precamres.2025.107962","url":null,"abstract":"<div><div>The Ediacaran–Cambrian transition represents a pivotal interval in Earth’s history, marked by the emergence of tubular organisms during the Late Ediacaran and the subsequent appearance of modern animal phyla in the early Cambrian. However, such tubular organisms have never been described from the Neoproterozoic cover of the West African Craton, leaving a gap in our understanding of their exact paleogeographic distribution during this critical evolutionary period.</div><div>In this study, we describe the first occurrence of tubular fossils from the Late Ediacaran Lower unit of the Tabia Member (Taroudant Group) of the Anti-Atlas (Morocco), including <em>Conotubus</em> and cf. <em>Wutubus</em>, as well as associated oldest trace fossils (e.g., <em>Helminthoidichnites</em> and <em>Gordia</em>) and microbial structures (<em>Ivesheadiomorphs</em>) from shallow marine tidal flat and peritidal environments. <em>Conotubus</em> consists of fully pyritized, annulated tubular fossils with distinct apex–aperture differentiation. cf. <em>Wutubus</em> is characterized by annulated impressions with similar apex–aperture features. Notably, cf. <em>Wutubus</em> from the Anti-Atlas preserves a discoidal holdfast, supporting the interpretation of this taxon as a sessile organism.</div><div>The integration of these new data within both regional and global frameworks provides new insights into the Ediacaran–Cambrian boundary in the Anti-Atlas, expands the known paleogeographic distribution of <em>Wutubus</em> to the northern margin of Gondwana, and raises important questions regarding the biostratigraphic distribution of ichnotaxa such as <em>Monomorphichnus and Treptichnus bifurcus</em>.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107962"},"PeriodicalIF":3.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145467529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Age and metamorphic P–T evolution of Pelitic Granulites from the Irkut Terrane, Siberian Craton: implications for neoarchean collisional orogenesis","authors":"Vasiliy Sukhorukov,&nbsp;Olga Turkina","doi":"10.1016/j.precamres.2025.107956","DOIUrl":"10.1016/j.precamres.2025.107956","url":null,"abstract":"<div><div>The first data on P–T metamorphic conditions, coupled with U–Pb monazite and zircon ages, were obtained for Neoarchean aluminous gneisses in the central part of the Irkut terrane (the Sharyzhalgay uplift of the Siberian craton). Based on petrological observations, conventional geothermobarometry and thermodynamic modelling, the peak P-T conditions of metamorphism were found to be 760–780 °C and 6–6.8 kbar. This was followed by a ’clockwise’ retrograde P-T path involving episodes of near-isothermal decompression and subsequent cooling, which is typical of collisional settings. Coupled U-Pb dating of zircon and monazite indicates that the metamorphism occurred approximately 2.55 billion years ago. Combining these new data with the Neoarchean age of the granitoids suggests a collisional event occurred in the eastern part of the Sharyzhalgay uplift around 2.55 Ga. The P-T parameters and P-T paths of Neoarchean metamorphism are similar to those of Paleoproterozoic collision-related metamorphism in the Irkut terrane. This implies that the tectonic settings were similar during these two periods.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107956"},"PeriodicalIF":3.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145419353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pre-Mesoproterozoic crustal framework and Mesoproterozoic evolution of the SW Angolan Shield: structural, geochemical, and isotopic insights from the Kunene Complex and surrounding basement","authors":"Enrique Merino-Martínez ,&nbsp;Ezequiel Ferreira ,&nbsp;Pablo Valverde-Vaquero ,&nbsp;José Feliciano Rodrigues ,&nbsp;Javier Escuder-Viruete ,&nbsp;José Luis García-Lobón ,&nbsp;Aratz Beranoaguirre ,&nbsp;María del Carmen Feria ,&nbsp;Carmen Rey-Moral ,&nbsp;Paulo Bravo Silva ,&nbsp;Pablo González-Cuadra ,&nbsp;João Carlos Sousa ,&nbsp;Julián Potti ,&nbsp;Jaime Máximo ,&nbsp;Miguel Gutiérrez-Medina ,&nbsp;Juan Carlos Gumiel ,&nbsp;Gustavo Galán ,&nbsp;Tania Mochales ,&nbsp;José Manuel ,&nbsp;Domingos Cordeiro ,&nbsp;Carmen Galindo","doi":"10.1016/j.precamres.2025.107937","DOIUrl":"10.1016/j.precamres.2025.107937","url":null,"abstract":"<div><div>The southwestern Angolan Shield hosts the Earth’s largest Mesoproterozoic massif-type anorthosite complex (up to 53,500 km²), the Kunene Complex (KC). This complex is the result of a long-lived (∼200 Ma) episodic emplacement of coalescent magmatic pulses. The recent acquisition of multidisciplinary data during the PLANAGEO project has significantly enhanced our understanding of the Precambrian crustal framework from the southwestern Angolan Shield. Combined multi-isotope, structural and geophysical data reveals distinctive crustal zones in the southwestern Angolan Shield that clearly influenced KC’s emplacement within a back-arc setting. The spatio-temporal arrangement of KC pulses suggests westwards magma migration within a complex contractional regime involving large strike-slip systems. A long-lasting and extensive accretionary orogen was responsible for the tectono-thermal activity recorded during most of the Mesoproterozoic. Crustal thinning and partial melting of isotopically heterogeneous lower-crustal sources through mantle upwelling promoted the episodic felsic magmatism contemporaneous with the KC. Crustal contamination processes are evident in gabbro-anorthosites, indicating mantle metasomatism and interaction with wall-rocks and granite melts during ascent, upwelled by lateral-driven forces. Deposition of extensive metasedimentary sequences (&lt;1.26 Ga) covering the KC, along with 1.23–1.07 Ga sublithospheric and mantle-derived magmatism, indicate a shift from a compressional to an extensional regime during late-Mesoproterozoic times. Regional correlations with other Mesoproterozoic units in African and Brazilian counterparts suggest a shared geological evolution, despite potential differences in tectonic setting. These findings supports a refined geological model for the Mesoproterozoic evolution of the southwestern part of the Congo Craton.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107937"},"PeriodicalIF":3.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145327169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cryptic foreland basin strata of the southeastern Trans-Hudson Orogen revealed by detrital zircon geochronology","authors":"Jared P. Butler ,&nbsp;Alana M. Hinchey ,&nbsp;James L. Crowley","doi":"10.1016/j.precamres.2025.107961","DOIUrl":"10.1016/j.precamres.2025.107961","url":null,"abstract":"<div><div>Paleoproterozoic sedimentary sequences in the New Québec Orogen (NQO), northeastern Canada, record a complete Wilson cycle related to opening of the Manikewan Ocean and later Trans-Hudson orogeny. However, pinpointing the transition from extensional tectonics to foreland basin deposition has proved challenging owing to the composite character of the basin and a paucity of age constraints. We present results from a detrital zircon geochronological study of sedimentary rocks from cycles 1 to 3 of the Kaniapiskau Supergroup, in the foreland of the NQO, designed to assesses sediment provenance, determine maximum depositional ages (MDAs), and evaluate tectonic models. Cycle 1 sandstones yielded predominantly Neoarchean zircon and MDAs as young as 2365 ± 24 Ma, consistent with deposition during well-documented ca. 2.17 Ga rifting. Samples from Cycle 2, previously dated at ca. 1.88 Ga and variously ascribed to renewed rifting or development of a foreland basin, reveal a composite sequence comprising elements of both tectonic settings. Data from the Wishart Formation, the base of Cycle 2, are consistent with previously determined ca. 1.88 Ga ages for associated extensional magmatism, supporting deposition during a second phase of rifting. The stratigraphically higher Menihek Formation, meanwhile, yielded abundant Orosirian (ca. 2050–1800 Ma) zircon and MDAs as young as 1836.88 ± 1.08 Ma, indicating a pronounced hiatus and change in provenance. The unconformably overlying Tamarack River Formation (Cycle 3), widely interpreted as synorogenic molasse, produced bimodal age spectra with Orosirian and Neoarchean populations, and MDAs of 1815.00 ± 0.90 Ma. Late Orosirian zircon in the Menihek and Tamarack River formations was likely sourced from a ca. 1840–1810 Ma magmatic arc to the east of the NQO, suggesting that these units represent a foreland basin developed during Trans-Hudson orogenesis. Turbidite deposition in the underfilled foreland basin began &lt; ca. 1836 Ma following collision between the distal Superior craton and the Core Zone. Later, ca. 1815 Ma fluvial deposition of the Tamarack River Formation above deformed and eroded Menihek Formation probably reflects westward migration of the orogenic wedge and overfilling of the basin. The cryptic transition between precursor and foreland basin strata in the NQO highlights the importance of detrital zircon studies for investigating ancient basins with complex tectonic histories.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107961"},"PeriodicalIF":3.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145419356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Petrogenesis of the Paleoproterozoic Wulong Gabbros: Insights into the post-collisional evolution of the southern North China Craton","authors":"Jian-Feng Ma ,&nbsp;Hamed Gamaleldien ,&nbsp;Yan-Yan Zhou ,&nbsp;Tai-Ping Zhao","doi":"10.1016/j.precamres.2025.107945","DOIUrl":"10.1016/j.precamres.2025.107945","url":null,"abstract":"<div><div>The North China Craton (NCC) has preserved nearly 3.8 billion years (Ga) of Earth’s evolutionary history. Although the formation and amalgamation mechanism of the NCC remains debated, it is widely accepted that its final collisional assembly was completed at ∼1.85 Ga, followed by over a billion years of stability. However, the timing of the post-collisional extension is not well constrained, leaving uncertainties in the mantle and crustal evolution processes after the craton’s formation. Here, we present new detailed geochronological, petrological, and geochemical data of Paleoproterozoic Wulong gabbros to investigate their origin and tectonic implications for the evolution of the NCC. Zircon and titanite U–Pb isotopic dating indicate that the Wulong gabbros formed at 1830 ± 19 Ma. The Wulong gabbros have low SiO₂ (49.4–52 wt%) and variable contents of MgO (3.9–7.2 wt%) with sub-chondritic Nd isotope compositions (εNd_(t) from −7.34 to −3.26), suggesting it was derived from the enriched mantle source. Reverse crystallization calculations indicate that the primary melts exhibit low SiO₂ (∼48.1 wt%) and high MgO (∼16.3 wt%) contents, along with moderate mantle potential temperatures (∼1361 °C) and pressures (∼1.83 GPa or ∼60 km). The new results suggested that the source magmas formed through 3–5 % partial melting of a spinel-bearing lithospheric mantle previously metasomatized by 0.5–10 % subduction-related fluids. The generated parental basaltic melt underwent fractional crystallization and minor plagioclase accumulation at approximately 1 GPa. Our new findings highlight that the Wulong gabbros were sourced from the extensional lithospheric mantle but stored in the thickened crust, marking the onset of post-collision extension in the North China Craton. Our work also highlights the asynchronous nature of mantle and crustal extension during the post-collisional stage and provide important insights into the Wilson cycle.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"431 ","pages":"Article 107945"},"PeriodicalIF":3.2,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145365662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Aravalli A-type granites (ca. 1.72 Ga), NW India: Petrogenesis, geodynamic evolution, and global implications for late Paleoproterozoic crustal reworking","authors":"Parampreet Kaur ,&nbsp;Armin Zeh ,&nbsp;Naveen Chaudhri ,&nbsp;Prabhakar Dutta ,&nbsp;Axel Gerdes","doi":"10.1016/j.precamres.2025.107936","DOIUrl":"10.1016/j.precamres.2025.107936","url":null,"abstract":"<div><div>The geochemical and isotopic data for ca. 1.72 Ga A-type granites in the central Aravalli orogen, NW India, remain limited, hindering a detailed evaluation of their petrogenesis and tectonic setting. New results of combined zircon U-Pb-Hf isotope analyses and whole-rock geochemical data reveal that the A-type granites are characterised by high liquidus temperatures (≥850 °C), enrichment in rare earth elements and incompatible elements, and oxidised in nature. They were generated through partial melting of a silica-poor dioritic source within a post-collisional extensional setting. This A-type magmatism is synchronous with the emplacement of charnockites and granulite-facies metamorphism in the region. The coeval formation of A-type and charnockite magmas is attributed to partial melting of evolved Neoarchean crust (εHf_t = -12.5 to −5.2 and T_DM2 = 3.02 to 2.68 Ga) at moderate depth (20–25 km), triggered by upwelling of asthenospheric mantle following a slab break-off at ca. 1730 Ma. This process induced lithospheric extension and granulite-facies metamorphism in the lower crust. A global compilation of zircon Hf isotope and whole-rock Nd isotope data for late Paleoproterozoic A-type granites suggests that these rocks primarily formed by large-scale reworking of existing crustal sources, with only limited melt contributions from depleted mantle sources, thereby having a negligible impact on crustal growth over time. On the contrary, the Phanerozoic A-type granites largely represent addition of new crust.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107936"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unprecedented U–Pb-Th SHRIMP and Lu–Hf isotopic data in zircon from Tandilia basement rocks, Argentina: new insights into Palaeoproterozoic and Neoproterozoic crustal reworking of the Río de la Plata craton","authors":"Melisa Angeletti ,&nbsp;Martim Chichorro ,&nbsp;Antonio Castro ,&nbsp;María Cristina Frisicale ,&nbsp;Rita Solá ,&nbsp;Luis Vicente Dimieri ,&nbsp;Juan Cruz Martínez","doi":"10.1016/j.precamres.2025.107941","DOIUrl":"10.1016/j.precamres.2025.107941","url":null,"abstract":"<div><div>We present new geochronological zircon data from the Siempre Amigos Hill (SAH), a small but representative portion of Tandilia Terrane within the Río de la Plata Craton (RPC). U-Pb-Th SHRIMP data indicate a heterogeneous Palaeoproterozoic (Rhyacian) crust. A garnet-bearing granite (2165 ± 16 Ma) hosts felsic (2108 ± 13.6 Ma) to intermediate gneiss protolith (2104 ± 8 Ma), andesite with a sanukitoid signature (2094 ± 47 Ma) and granulites or charnockites. Additionally, calc-alkaline granitoids (2092 ± 13 Ma) intruded, as a result of differentiation from an igneous mafic sanukitoid source. Localised low-temperature shear zones affected the sequence. Lu-Hf isotopic data for the post-orogenic stage (&lt; 2.1 Ga) complement previous results, showing progressive negative _ƐHf_(t) values. These isotopes suggest post-orogenic transtension. New Neoproterozoic ages (652 ±37 Ma, 618.4 ±11.2 Ma and 686 ±60 Ma) from granites, with low-to-very low zircon Th/U ratios, are presented as evidence of U-Th-Pb systems overprinting by Neoproterozoic (Cryogenian) thermal-hydrothermal events. Those Neoproterozoic ages are, within analytical uncertainty, equivalent to the 656 ± 19 Ma metamorphic age obtained for the Palaeoproterozoic granulite. These new Neoproterozoic ages, suggests a thermal perturbation linked either to the collision of the Nico Pérez Terrane against the passive margin of RPC, or the Neoproterozoic evolution of the Ventania System basement during the Brasiliano/ Pan-African orogeny.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107941"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145333340","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metamorphic timescales of Neoproterozoic high-pressure granulites constrained by multi-mineral petrochronology: A case study from the Southern Brasília Orogen (SE Brazil)","authors":"Lorena de Toledo Queiroz ,&nbsp;Brenda Chung Rocha ,&nbsp;Bruno Vieira Ribeiro ,&nbsp;Cauê Rodrigues Cioffi ,&nbsp;Vinícius Tieppo Meira ,&nbsp;Lucas Ramos Tesser ,&nbsp;Armando Lucas Souza de Oliveira ,&nbsp;Gyovana Patrícia Gonçalves Costa ,&nbsp;George Luiz Luvizotto","doi":"10.1016/j.precamres.2025.107943","DOIUrl":"10.1016/j.precamres.2025.107943","url":null,"abstract":"<div><div>Timescales of Neoproterozoic high-pressure granulites from the Carvalhos Klippe (Southern Brasília Orogen) were constrained through multi-mineral petrochronology. The high-grade metamorphism is related to continental collision processes during the assembly of West Gondwana and provides valuable insights on duration and rates of collisional settings in the Neoproterozoic. Most of the investigated samples comprises coarse-grained rutile-kyanite-garnet-orthoclase granulites, reaching peak metamorphic conditions of ∼ 825 °C and 12 kbar, based on phase equilibrium modelling and Zr-in-rutile thermometry. Prograde to a near peak stage (630–620 Ma) was constrained by garnet Lu-Hf and U-Pb ages from high Y-HREE and low Th/U monazite domains. Low Y-HREE, high Th/U and Eu/Eu* monazite domains record the metamorphic peak (615–605 Ma) after substantial garnet growth, presence of melt and plagioclase consumption. The retrograde stage highlighted by high Y-HREE and Th/U and depleted Eu/Eu* monazite domains, reflects garnet dissolution and melt crystallization during the retrograde path (605–600 Ma). Zircon ages have a main cluster between 630 and 605 Ma, most likely related to near-peak cooling. Cooling ages obtained by rutile and apatite U-Pb and biotite Rb-Sr ranging from 570 to 540 Ma suggest slow cooling rates of 2–8 °C/Myr during the retrograde path, contrasting with the modern collisional orogens due to hotter mantle temperatures or low erosion rate and/or heat-producing elements concentration. This study demonstrates that the timescales of high-pressure granulites may provide a robust framework for understanding continental settings throughout the Earth’s history.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107943"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268581","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Were there any snow algae on the Cryogenian ‘Snowball Earth’?","authors":"Morten Smelror","doi":"10.1016/j.precamres.2025.107935","DOIUrl":"10.1016/j.precamres.2025.107935","url":null,"abstract":"<div><div>Unicellular algae have unique adaptation capacities for primary production in different extreme environments. In Neoproterozoic times (1000–542 Ma) a group of green algae developed evolutionary production and survival strategies like those of modern snow algae, and during the Cryogenian Sturtian and Marinoan global glaciations these algae inhabited ice covered shelves. To what extent snow algae existed on inland glaciers and snow-covered terrains is discussed. Evidence supporting a ‘Snowball Earth’ with terrestrial biomes and snow algae are morphological resemblances between aplanospores of modern cryophilic microalgae (Chlamydomonadaceae) found in high mountains in central Norway and Meso- and Neoproterozoic clusters of organic-walled microfossils and sphaeromorphic acritarchs. Geochemical biomarkers in Proterozoic rocks also provide possible links to carotenoids found in modern ‘red snow’. The abundant and diverse communities of present-day continental snow algae on glaciers and snow fields around the world may serve as a modern analogue to the Neoproterozoic ‘Snowball Earth’ glacial terrestrial biomes.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107935"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145268580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedimentary model evolution and palaeoenvironmental significance of the Upper Ediacaran microbial dolomites","authors":"Yuan Zhou ,&nbsp;Xuelian You ,&nbsp;Qing Li ,&nbsp;Zhuofeng Zhang ,&nbsp;Qiang Du ,&nbsp;Zhengyu Wei ,&nbsp;Xinlong Li ,&nbsp;Hui Zhou","doi":"10.1016/j.precamres.2025.107934","DOIUrl":"10.1016/j.precamres.2025.107934","url":null,"abstract":"<div><div>Microbial dolomites are extensively developed in the upper Ediacaran Dengying Formation (<em>ca</em> 551.1 to 542.0 Ma) in the Sichuan Basin, China. However, these microbial dolomites underwent complex depositional processes, and their sedimentary environments remain debated. In this study, the petrographic, mineralogical, and geochemical characteristics of microbial dolomites in the upper Ediacaran Dengying Formation are systematically analyzed. The microbial dolomites (stromatolites, thrombolites, oncoids, botryoidal dolomites) in the upper Ediacaran Dengying Formation demonstrate the interplay between microbial activity and environmental conditions in a shallow restricted platform. Microbial structural diversity reflects hydrodynamic-microbial synergy: stromatolites and botryoidal dolomites are formed in low-energy, high-activity settings; dispersed thrombolites are formed under weak microbial influence; layered/reticular thrombolites and oncoids are developed via particle aggregation in high-energy environments. Two transgressive–regressive cycles correlate with “dolomite sea” events: the first driven by global climate (evaporation, localized anoxia), the second by tectonic uplift (Tongwan Movement I), underscoring tectonics’ role in reservoir genesis. Geochemical indicators reflect post-glacial seawater stratification and weathering shifts, constraining environmental triggers for Ediacaran-Cambrian biotic complexity. Global comparisons reveal widespread microbial diagenesis during the Ediacaran, yet the Sichuan Basin exhibits unique tectono-climatic cyclicity. Although diagenesis obscures some geochemical signals, systematic analysis confirms the Dengying Formation as a critical archive for Precambrian carbonate factory evolution, microbial-environmental feedbacks, and early reservoir dynamics. This study advances understanding of late Precambrian Earth systems, bridging microbial processes, seawater chemistry, and tectono-climatic controls on carbonate preservation.</div></div>","PeriodicalId":49674,"journal":{"name":"Precambrian Research","volume":"430 ","pages":"Article 107934"},"PeriodicalIF":3.2,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}