Palaeogeography, Palaeoclimatology, Palaeoecology最新文献

{"title":"Improving the temporal resolution of middle Eocene–late Oligocene foraminiferal biomagneto-chronology: Insights from CONOP and chronologic significance of biotic events","authors":"Zhengbo Lu ,&nbsp;Junxuan Fan ,&nbsp;Bridget S. Wade ,&nbsp;James Ogg ,&nbsp;Laia Alegret ,&nbsp;Peter M. Sadler ,&nbsp;Michael H. Stephenson ,&nbsp;Yukun Shi ,&nbsp;Chao Qian ,&nbsp;Ke Xue ,&nbsp;Peiyue Fang","doi":"10.1016/j.palaeo.2025.112929","DOIUrl":"10.1016/j.palaeo.2025.112929","url":null,"abstract":"<div><div>To understand Earth's history, a comprehensive time scale integrating available stratigraphic information is crucial. The middle Eocene to late Oligocene offers abundant stratigraphic information, including foraminiferal and magnetostratigraphic data. However, traditional biostratigraphy uses only a small fraction (1–10 %) of foraminifera as markers, reducing the time scale's temporal resolution and lacking a quantitative method to assess the chronologic significance of both mearker and non-marker biotic events. This study employs the quantitative stratigraphic method, Constrained Optimization (CONOP), using 11 reference sections to create a high-resolution magneto-foraminiferal time scale for the middle Eocene–late Oligocene. The new composite sequence improves temporal resolution by nearly tenfold over traditional methods, incorporating 409 additional biotic events while aligning closely with established markers. Two evaluation factors, diachrony and centrality, were developed to assess the temporal consistency of events among different locations and geographic ranges. Findings reveal that the chronological significance of small benthic foraminifera, planktonic foraminifera, and foraminiferal zonal species events increases sequentially. Conversely, larger benthic foraminiferal events are affected by endemism, complicating their evaluation. Incorporating magnetostratigraphic data into CONOP enhances the robustness and accuracy of stratigraphic correlation. Our approach offers a way to apply CONOP for high-resolution time scales, allowing for a comprehensive assessment of biotic events beyond the use of zonal fossils.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"669 ","pages":"Article 112929"},"PeriodicalIF":2.6,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143786223","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":"Quantifying the equatorial climate shifts in the Indo-Burma range using late Eocene–early Oligocene leaf fossils","authors":"Harshita Bhatia ,&nbsp;Kapesa Lokho ,&nbsp;Gaurav Srivastava ,&nbsp;O. Chonchibeni Ezung","doi":"10.1016/j.palaeo.2025.112931","DOIUrl":"10.1016/j.palaeo.2025.112931","url":null,"abstract":"<div><div>The late Eocene–early Oligocene geological time span saw significant Antarctic glaciation, which played a crucial role in shaping global climate patterns and influencing regional climates and ocean circulation changes. In this study, we quantitatively reconstructed the climate of a low latitude site using fossil leaf morphological traits recovered from the Laisong Formation (late Eocene–early Oligocene) of the Indo-Burma range. The Climate Leaf Analysis Multivariate Program was used to quantify the climate, suggesting a mean annual temperature of 25.3 ± 2.3 °C and a cold month mean temperature of 19.2 ± 3.5 °C. The length of the growing season extended throughout the year, with a mean annual precipitation of 244.2 ± 64.3 cm, showing clear rainfall seasonality between rainy summers (130 ± 40 cm) and dry winters (21.7 ± 9.8 cm). The study further reveals that high rainfall in the low latitude region resulted from the northward migration of the intertropical convergence zone due to Antarctic glaciation.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"669 ","pages":"Article 112931"},"PeriodicalIF":2.6,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143783230","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":"Dental microwear of bovids from the Pliocene-Pleistocene transition in the lower Awash Valley, Ethiopia","authors":"A.G. Kirkpatrick ,&nbsp;I.A. Lazagabaster ,&nbsp;J.R. Robinson ,&nbsp;J. Rowan ,&nbsp;C.J. Campisano ,&nbsp;K.E. Reed ,&nbsp;J.R. Scott ,&nbsp;P.S. Ungar","doi":"10.1016/j.palaeo.2025.112932","DOIUrl":"10.1016/j.palaeo.2025.112932","url":null,"abstract":"<div><div>Ethiopian fossil sites in the Lee Adoyta basin at Ledi-Geraru and the Maka'amitalu basin at Hadar straddle the Pliocene-Pleistocene transition and have both yielded fossil hominins attributed to early <em>Homo</em>. Faunal remains at these sites hold potential for providing insights into the ecological backdrop of the transition between these epochs in the lower Awash Valley and, by extension, the environments associated with the first appearance of <em>Homo</em> in the fossil record. Herbivore guild composition, ecomorphological study, and isotope analyses suggest that compared with paleoenvironments at earlier sites in the lower Awash, those in the Lee Adoyta basin and at Maka'amitalu had higher abundances of tropical grasses and sedges relative to browse plants. Here we bring another proxy to bear on the environments of the Lee Adoyta basin and Maka'amitalu associated with early <em>Homo</em>, dental microwear texture analysis. Dental microwear has been shown to separate grazing from browsing bovids and, because food choice reflects availability, can by extension provide insights into habitat. We employ texture analysis to infer the diets of bovid individuals from the Lee Adoyta basin (<em>n</em> = 13) and Maka'amitalu (<em>n</em> = 6) that preserve antemortem microwear. High-resolution replicas were scanned with a white-light confocal profiler and texture complexity and anisotropy were calculated for each surface and compared with baseline data for an extant sample of grazers, browsers, and mixed feeders. Values for bovids from the two sites do not differ from one another. Both samples have high anisotropy and low complexity, suggesting a graze-dominated diet and wide availability of grasses at both sites. These results are consistent with conclusions derived from other proxies.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"670 ","pages":"Article 112932"},"PeriodicalIF":2.6,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143835149","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":"Small shelly fauna biodiversity from reef-adjacent facies of the lower Cambrian Harkless Formation, Nevada","authors":"Casey C. Bennett,&nbsp;Clare Mate,&nbsp;Sarah M. Jacquet","doi":"10.1016/j.palaeo.2025.112922","DOIUrl":"10.1016/j.palaeo.2025.112922","url":null,"abstract":"<div><div>Cambrian archaeocyathid reef systems represent the earliest metazoan-dominated topographically complex bioconstructions in the rock record and provide valuable insights into community composition with respect to the major framework builders and their small shelly fossil (SSF) inhabitants. This study quantified variations in the composition of SSF assemblages (richness, evenness, and diversity) in relation to proximity to biohermal facies of the lower Cambrian (Series 2, Stage 4) Harkless Formation in southern Esmeralda County, Nevada. Combining petrographic and quantitative analyses with a systematic review of the SSFs reveals a low diversity, but abundant assemblage. Trends in species richness, evenness and diversity show no consistent patterns in distance from the reef across the measured sections. However, lithology serves as a major control in determining SSF biofacies, with select fauna exhibiting evidence of taphonomic controls. More research is needed to investigate spatial relationships of shelly faunas across these ancient carbonate archaeocyathid reefs and platforms to determine the role early reef habitats have on local biodiversity.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"669 ","pages":"Article 112922"},"PeriodicalIF":2.6,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143808660","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":"Precipitation patterns and variability in Tropical Americas during the Holocene","authors":"Paula R. Bianchini ,&nbsp;Luciana F. Prado ,&nbsp;Elder Yokoyama ,&nbsp;Ilana Wainer ,&nbsp;Iuri Gorenstein ,&nbsp;Francesco S.R. Pausata","doi":"10.1016/j.palaeo.2025.112935","DOIUrl":"10.1016/j.palaeo.2025.112935","url":null,"abstract":"<div><div>The Tropical Americas (TA) have monsoons as the dominant feature of their hydroclimate. Precipitation in this region is influenced by the American Monsoon System (AMS). Throughout the Holocene, several global climate changes occurred that modified precipitation patterns in this region. Here we identify a general trend of increasing precipitation in the TA over the last 11,700 years. We analyzed different precipitation datasets, as paleorecords from lake sediments and speleothems, and Transient Climate Simulation of the Last 21,000 Years (TraCE-21ka) model results. We also identified occasional shifts in the TA's precipitation during the Holocene, with variations in the pattern of precipitation anomalies around 9,000 to 8,000 years, corroborated by high-energy wavelet analysis signals detected before 7,710 years. These results show that TA's precipitation was influenced by the final collapse of the North American ice sheets, accelerated by increased summer insolation in Northern Hemisphere (NH).</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"669 ","pages":"Article 112935"},"PeriodicalIF":2.6,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143783231","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":"Holocene coral assemblages reveal similarities to living communities in Singapore's urban reef environment","authors":"Y.K. Samuel Chan ,&nbsp;Ambert C.F. Ang ,&nbsp;Min Choo ,&nbsp;Ren Min Oh ,&nbsp;Kyle M. Morgan ,&nbsp;Peter A. Todd ,&nbsp;Michael J. O'Leary ,&nbsp;Danwei Huang","doi":"10.1016/j.palaeo.2025.112930","DOIUrl":"10.1016/j.palaeo.2025.112930","url":null,"abstract":"<div><div>Coral reefs in Southeast Asia represent some of the most diverse marine systems in the world. These reefs have also experienced high levels of anthropogenic impacts from coastal development and climate change. Understanding historical baselines of reefs in the region can help guide analyses and projections of how corals may respond to different environmental changes. Here, we extracted 20 reef cores from five sites in Singapore to characterise the growth, diversity and community structure of coral assemblages through the Holocene and for comparison with modern reefs. Based on radiocarbon dating and analysis of corals in the cores, we established that reef initiation began approximately 8000 years before present (BP) with nearly all corals dated to between that time and about 4000 years BP. Past coral assemblages reconstructed from the core material were dominated by stress-tolerant genera <em>Porites</em>, <em>Goniopora</em> and <em>Euphyllia</em>, but these were lower in relative abundances compared to modern communities dominated also by Merulinidae and <em>Pachyseris</em>. Past assemblages also hosted lower coral richness compared to modern assemblages. Grain size analysis of the sediment matrix showed a shift towards finer material (i.e. fine sand, silt and clay; &lt;500 μm) downcore. Transitions in coral assemblages were also observed, but no specific depth-related patterns were apparent. Together, these results indicate that reef assemblages in Singapore have persisted throughout the Holocene in a turbid environment, dominated by stress-tolerant corals with limited community change through the millennia. Despite this long-term persistence, observed losses of corals in recent decades suggest that those adapted to turbid reefs remain vulnerable to excessive environmental change and require active intervention to halt the current decline trajectory.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"669 ","pages":"Article 112930"},"PeriodicalIF":2.6,"publicationDate":"2025-04-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143799264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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":"Genesis of manganese-rich deposits in the Mesoproterozoic Gaoyuzhuang Formation, North China: Implications for atmospheric redox state and early eukaryote evolution","authors":"Lingtong Xu ,&nbsp;Wenchao Yu ,&nbsp;Kurt O. Konhauser ,&nbsp;Hua Guo ,&nbsp;Song Jin ,&nbsp;Pengfei Ma ,&nbsp;Yuansheng Du","doi":"10.1016/j.palaeo.2025.112924","DOIUrl":"10.1016/j.palaeo.2025.112924","url":null,"abstract":"<div><div>Precambrian Mn deposits account for more than 77 % of global Mn resources, with most formed during periods of significant atmospheric oxygenation: the Paleoproterozoic Great Oxidation Event (GOE) and the Neoproterozoic Oxidation Event (NOE). The intervening interval, between 1.8 and 0.8 Ga, has historically been labelled as the “boring billion” without significant sedimentary Mn accumulation. However, recent studies have revealed episodic oxygenation events during the Mesoproterozoic, accompanied by distinct Mn-rich sediments. This study reports on the petrography, mineralogy, whole-rock, and carbonate fraction geochemistry of the ∼1.56 Ga Mn-rich sediments within the lower 2nd Member of the Gaoyuzhuang Formation in the Yanliao Basin, North China. Sedimentological evidence indicates that these Mn-rich deposits formed along the continental shelf margin during a transgression in the early Mesoproterozoic. Geochemical data, including weakly positive Eu anomalies (up to 1.22) and a positive correlation between Mn contents and εNd(t) (<em>n</em> = 10, r = +0.74, <em>p</em>(α) = 0.01), suggest that dissolved Mn²⁺ was derived from distal hydrothermal vents. This conclusion is further supported by discrimination diagrams constructed from both whole-rock and carbonate fraction data. The Mn(II)-bearing minerals are dominated by rhodochrosite and kutnohorite. Microscopic features and negative δ¹³C_carb values (−6.72 ‰ to −1.08 ‰, avg. = −4.43 ‰) suggest that rhodochrosite formed during early diagenesis, while kutnohorite precipitated from both anoxic seawater and sediment porewater. Subsequent Mn(IV)-oxide reduction occurred during diagenesis (affecting all rhodochrosite and some kutnohorite) or near the redoxcline (for portions of kutnohorite), reflecting a pulsed oxygenation event. A sudden increase in Fe and S concentrations and the presence of layered pyrite indicate a transient euxinic environment immediately following Mn deposition. This euxinia was probably driven by enhanced oxidative weathering on land, which increased sulfate fluxes to the ocean. Thereafter, δ¹³C_carb became decoupled from δ¹³C_org, likely due to the expansion of the oceanic dissolved organic carbon (DOC) reservoir. This expanded DOC reservoir may have been oxidized immediately prior to the appearance of macroeukaryotes in the overlying 3rd Member of the Gaoyuzhuang Formation. Notably, sustained oxygenated surface conditions capable of supporting a diversified eukaryotic ecosystem likely emerged only after the oxidation of excess DOC and electron donors (e.g., Mn²⁺ and Fe²⁺). Therefore, we propose that the rising atmospheric oxygen levels during the deposition of the lower 2nd Member of the Gaoyuzhuang Formation, combined with the expanded DOC reservoir, created conditions favourable for macroeukaryotes evolution.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"668 ","pages":"Article 112924"},"PeriodicalIF":2.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760210","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":"Early to Late Triassic conodont biostratigraphy in the Lhasa Terrane","authors":"Yongxi Li ,&nbsp;Zhansheng Ji ,&nbsp;Guichun Wu ,&nbsp;Paul B. Wignall ,&nbsp;Yan Chen ,&nbsp;Zaitian Zhang ,&nbsp;Shaowen Zhang ,&nbsp;Xulong Lai","doi":"10.1016/j.palaeo.2025.112927","DOIUrl":"10.1016/j.palaeo.2025.112927","url":null,"abstract":"<div><div>The Coqen area of the Lhasa Terrane, Xizang (Tibet, Southwest China) has provided key evidence for understanding Triassic history in the region. However, the stratigraphic subdivision of the Middle to Upper Triassic remains unclear. Here we present new results on the conodont biostratigraphy at Dibuco, a section in the Lhasa Terrane. Sixteen genera and forty-three species are identified, including one new species: <em>Borinella dibucoensis</em> sp. nov. of the Spathian (Olenekian) age. Eight conodont zones are established from the Late Olenekian to the Early Norian. These are, in ascending order, <em>Triassospathodus homeri - Columbitella jubata</em> Zone, <em>Neogondolella constricta</em> Zone, <em>Paragondolella praeszabόi</em> Zone, <em>Budurovignathus mungoensis</em> Zone, <em>Quadralella polygnathiformis</em> Zone, <em>Quadralella praelindae</em> Zone, <em>Carnepigondolella oertlii - Carnepigondolella nodosa</em> Zone and <em>Ancyrogondolella</em> aff. <em>quadrata</em> Zone. This is a relatively complete conodont succession for eastern part of Tethys region and it shows close relationship with western Tethys and eastern Tethys (South China). Based on the conodont biostratigraphy, the base of Zhulong Formation, previously lacking a precise age assignment, is shown to be of late Anisian age.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"669 ","pages":"Article 112927"},"PeriodicalIF":2.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143783193","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":"Metallogenic process of the Precambrian graphite ores in the North China Craton and its response to the evolution of the Earth surface environment","authors":"Weibing Shen ,&nbsp;Weibin Shen ,&nbsp;Feng Li ,&nbsp;Xiao Xiao ,&nbsp;Yangyang Wang","doi":"10.1016/j.palaeo.2025.112926","DOIUrl":"10.1016/j.palaeo.2025.112926","url":null,"abstract":"<div><div>The North China Craton (NCC) is China's primary graphite production region, with over 90 % of the graphite ores from its Precambrian strata. Precambrian graphite ore formation in the NCC reflects coupled geological and environmental processes, but their relationship mechanism remains unclear. This paper, from the perspective of the evolution of earth surface environment, systematically analyzes the distribution pattern and metallogenic mechanism of Precambrian graphite ores in the NCC. Precambrian graphite ores are predominantly located at the margins of the craton and are primarily hosted within Paleoproterozoic strata. Precambrian graphite ores in the NCC are mainly regional metamorphic, with organic-derived carbon as the primary protolith carbon source. Their metallogenic process is a comprehensive response to the drastic changes of the surface lithosphere, biosphere, hydrosphere and atmosphere in the early Earth: 1) Numerous rift basins, formed by continental breakup and post-glacial sea level rise, provided ample space for carbon-rich protolith deposition. Concurrently, marine species innovation and biological productivity surges, linked to atmospheric oxygenation events, supplied the organic matter (OM) necessary for extensive carbon-rich protolith formation. 2) Cratonization and rift-related dynamic heat flow triggered regional metamorphism, activating carbon to form graphite crystals. These crystals grew further through thermal contact metamorphism, ultimately forming large-scale graphite ores. Although there is limited research on the feedback mechanisms of graphite mineralization on Earth's surface environmental evolution, the sedimentary areas for organic-rich protolites and regional metamorphic zones for carbon mineralization in the Precambrian period are superimposed to resulted in the formation of favorable metallogenic zones, where the magmatic thermal contact metamorphic zones are favorable exploration targets for high-grade crystalline graphite ores in the NCC.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"668 ","pages":"Article 112926"},"PeriodicalIF":2.6,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739640","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":"A refined biochemostratigraphic framework for the Induan","authors":"Sakineh Arefifard ,&nbsp;Thomas J. Algeo ,&nbsp;Feifei Zhang ,&nbsp;Tea Kolar-Jurkovšek ,&nbsp;Tahereh Parvizi","doi":"10.1016/j.palaeo.2025.112902","DOIUrl":"10.1016/j.palaeo.2025.112902","url":null,"abstract":"<div><div>The Early Triassic was an interval of protracted marine biotic recovery from a mass extinction, environmental change, and large shifts in carbon isotope records worldwide, yet the present geochronological framework for this interval has been cobbled together over time without formal definitions and placements of most stage and substage boundaries, impeding understanding of carbon-cycle perturbations and environmental changes during the recovery interval after the end-Permian mass extinction (EPME). Here, we generate high-resolution, unified biochemostratigraphic frameworks for two stratigraphically expanded Lower Triassic sections in Iran (Abadeh and Zal), which we compare and correlate with existing conodont and C-isotope records globally. Our new high-resolution carbon-isotope profiles for these sections record two negative shifts in the lower Dienerian (N2a) and mid-Dienerian (N2b) as well as two positive shifts in the upper Dienerian (P2a) and lower Smithian (P2b), clarifying δ¹³C_carb features that have been only intermittently noted in other Lower Triassic sections globally. Given the scarcity of conodonts in some marine sections, a high-resolution standard carbon isotope profile may prove useful in locating the boundaries of Induan substages. In the Iranian sections, the Griesbachian-Dienerian boundary (GDB) is located immediately below the N2a minimum, and the Induan-Olenekian boundary (IOB) is between the P2a and P2b peaks. Since the Iranian sections are among the most complete Induan successions globally, we propose them as auxiliary reference sections for formal definition of Lower Triassic substage boundaries, a task that remains uncompleted at present. We also undertake a review of Lower Triassic sections globally, summarizing key biostratigraphic (i.e., ammonoid and conodont) and chemostratigraphic (i.e., carbon isotope) data for multiple regions (e.g., the Boreal, Panthalassic, and Tethyan realms).</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"668 ","pages":"Article 112902"},"PeriodicalIF":2.6,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143760211","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}