Palaeogeography, Palaeoclimatology, Palaeoecology最新文献

{"title":"Marine redox evolution and organic matter accumulation in the end Guadalupian in NE Sichuan, South China","authors":"Xiaotong Ge ,&nbsp;Baojian Shen ,&nbsp;Daizhao Chen ,&nbsp;Yali Liu ,&nbsp;Ziwen Jiang ,&nbsp;Mu Liu ,&nbsp;Xun Ge","doi":"10.1016/j.palaeo.2025.112901","DOIUrl":"10.1016/j.palaeo.2025.112901","url":null,"abstract":"<div><div>The Guadalupian-Lopingian (G-L) transition represents a pivotal interval, during which changes in oceanic redox conditions have been proposed to correlate with the end-Guadalupian mass extinction. However, the detailed spatial and temporal variations in marine redox states are still not well-defined. To explore the concurrent oceanic shifts and the factors controlling organic matter accumulation, we investigate an organic-rich succession from the G-L boundary located in an intrashelf basin in the northeastern Sichuan Basin, Southwest China by means of multiple geochemical indicators, including organic carbon isotope, total organic carbon contents, iron speciation contents, mercury contents and major and trace elements contents. Our results delineate four distinct intervals (I-IV) of redox conditions based on Fe-Mo-U-V data, showing a sequence from suboxic to ferruginous, followed by euxinic, and returning to suboxic conditions. The euxinic phase appears to have been driven by a highly restricted basin environment combined with frequent volcanic episodes. Additionally, the primary productivity peaked in the Interval II₂, which may have been a key factor in the organic matter accumulation. Comparative analysis with studies from other regions indicates that the Paleo-Tethys was more anoxic and exhibited greater stagnation than the Panthalassa during the end-Guadalupian, with the severity of anoxia during the Permian-Triassic transition surpassing that of the G-L transition. Overall, the significant marine anoxia was confined to moderate depths, with varying onset times across different areas, and was notably absent in the pelagic basins. This pattern implies that anoxia might not have been the primary cause of the mass extinction event.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112901"},"PeriodicalIF":2.6,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643944","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":"Oceanic redox condition and the evolution of Ediacaran life: Evidence from nitrogen isotopes and biogenic silica in the Yangtze Block, South China","authors":"Zaiyun Wang ,&nbsp;Hansheng Cao ,&nbsp;Fajin Chen ,&nbsp;Kai Wei ,&nbsp;Chuang Bao ,&nbsp;Qinghua Hou ,&nbsp;Chunqing Chen ,&nbsp;Hanli Huang ,&nbsp;Qiuping Chen","doi":"10.1016/j.palaeo.2025.112903","DOIUrl":"10.1016/j.palaeo.2025.112903","url":null,"abstract":"<div><div>The late Ediacaran period witnessed the largest global carbon cycle disturbance in geological history, known as the “Shuram Excursion”, coinciding with the emergence of early complex multicellular life. While the rise in atmospheric and oceanic oxygen is seen as a major catalyst for this evolutionary leap, the link between oxygenation and Ediacaran diversification remains contested. To investigate this, we reported nitrogen, carbonate, and organic carbon isotopes, as well as biogenic silica (BSi) content from a drill core in the Yangtze Platform, South China. During the lower Shuram excursion, δ¹⁵N decreased from 5.9 ‰ to 2.9 ‰, suggesting a shrinking nitrate pool in the euphotic zone associated with intensified denitrification due to the expansion of the anoxic zone. During the middle Shuram excursion, a significant decline in δ¹³C_carb was accompanied by a rapid increase in δ¹⁵N (up to 5.8 ‰), which likely reflects a transitional redox state characterized by moderate denitrification in the water column, enriching the remaining nitrate in the photic zone with ¹⁵N. The subsequent decline in δ¹⁵N signatures likely reflects reduced water-column denitrification, driven by further ocean oxygenation and the deepening of the chemocline. The concurrent positive excursions in δ¹⁵N and negative δ¹³C_carb correspond to the peak in BSi contents, suggesting that the rise in seawater O₂ levels and the increase in surface nitrate concentrations provided a favorable environment for siliceous organisms. The geochemical signatures observed correspond with the diversification of ecologically important animal groups, emphasizing the accelerated evolution of the Avalon biota in oxygen and nitrate-enriched environments.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112903"},"PeriodicalIF":2.6,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643943","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":"Neoproterozoic rift-related mafic and felsic rocks from the Yangtze Block, South China: Insights into petrogenesis and tectonic evolution","authors":"Jibiao Zhang ,&nbsp;Yanxue Liu ,&nbsp;Heng Zhang ,&nbsp;Chenglong Shi ,&nbsp;Peiwen Liu","doi":"10.1016/j.palaeo.2025.112904","DOIUrl":"10.1016/j.palaeo.2025.112904","url":null,"abstract":"<div><div>Neoproterozoic rift-related magmatism along the margins of the Yangtze Block presents a valuable opportunity to study the tectonic evolution of South China and the geodynamic processes resulting from the breakup of Rodinia. In this paper, we report Neoproterozoic rhyolites, diabases, and granites from the Kangdian and Nanhua Rift basins along the western and southeastern margins of the Yangtze Block, respectively. The Suxiong (ca. 819–824 Ma) and Yejia (ca. 800–804 Ma) rhyolites exhibit high Na₂O + K₂O (7.07–8.67 wt%) and Zr + Nb + Ce + Y (355–930 ppm) contents, zircon saturation temperatures (821–920 °C), and 10,000 × Ga/Al ratios (2.28–4.28), indicating an affinity with A-type granites. These rhyolites have depleted Nd<img>Hf isotopic compositions (ε_Hf(t) = +1.8 to +5.6 and ε_Nd(t) = +3.5 to +4.9, respectively) and are characterized by low Sr/Y (0.14–1.42) and (La/Yb)_N (3.98–9.1) ratios, Mg^# (8–35) values, and high Fe/(Fe + Mg) (0.76–0.96) ratios, suggesting that they were generated primarily by the partial melting of quartzofeldspathic crustal rocks under low-pressure, high-temperature conditions. The ca. 812 Ma Dengxiangying diabases are of the calc-alkaline series, showing enrichments in LILEs and LREEs and depletions in HFSEs. Isotoptic data (ε_Hf(t) = +6.6 to +10.1, ε_Nd(t) = +3.4 to +5.8) suggest that they were derived from the partial melting of subduction-modified lithospheric mantle. The ca. 810 Ma Yifeng granites display a weakly peraluminous character, with low zircon saturation temperatures (752–806 °C), and 10,000 × Ga/Al (2.0–2.6) and Zr + Nb + Ce + Y (155–340 ppm) values, similar to those of I-type granitoids. These granites have depleted whole-rock Nd (+1.5 to +2.6) and zircon Hf (+4.0 to +7.2) isotopic compositions, indicating derivation from the remelting of Mesoproterozoic mafic crustal materials. By integrating the petrogenesis of these Neoproterozoic rift-related rocks, we consider that the Kangdian Rift was a back-arc basin produced in response to the long-term slab subduction beneath the western Yangtze Block, whereas the Nanhua Rift was a continental rift basin produced in response to the upwelling of asthenospheric mantle.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"668 ","pages":"Article 112904"},"PeriodicalIF":2.6,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685273","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":"Climate and lake ecosystem evolution over the last millennium on the north-eastern Tibetan Plateau: Insights from stable isotope records of gastropod shells in Xing Co","authors":"Yunqing Li ,&nbsp;Wanyi Zhang ,&nbsp;Siyao Liu ,&nbsp;Yanrong Zhang ,&nbsp;Xianyong Cao ,&nbsp;Fang Tian","doi":"10.1016/j.palaeo.2025.112896","DOIUrl":"10.1016/j.palaeo.2025.112896","url":null,"abstract":"<div><div>The evolution of alpine lake ecosystems on the north-eastern Tibetan Plateau (NETP) over the last millennium has been affected by climate change and human activity. This study reconstructs the palaeoclimate and lake productivity of Xing Co using carbon and oxygen isotopes from aquatic gastropod shells (<em>δ</em>¹³C_shell and <em>δ</em>¹⁸O_shell), grain-size, total organic carbon (TOC), total nitrogen (TN), and the TOC/TN (C/N) ratio. The highest lake productivity – during the Medieval Warm Period (MWP) – is likely linked to enhanced photosynthesis of aquatic plants and increased biomass within the lake. This increase was driven by warm, humid climate conditions, indicated by higher <em>δ</em>¹³C_shell values, lower <em>δ</em>¹⁸O_shell values, and increased coarse-grain content. In contrast, the significant decline in lake productivity during the Little Ice Age (LIA) resulted from deterioration of trophic status and restricted aquatic plant growth under colder, drier climate conditions. However, the decrease in lake productivity since 1950 CE, amid global warming, may be linked to increased soil erosion and sedimentation rate from intensified human activity and land-use changes. The combined effects of climatic shifts and human disturbances highlight the need for ongoing monitoring of lake ecosystems to understand their resilience and response to future environmental changes.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112896"},"PeriodicalIF":2.6,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643941","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 reconstruction for the western Chinese Loess Plateau since 1598 CE reveals recent wetting signals","authors":"Yue Li ,&nbsp;Feng Chen ,&nbsp;Xiaoen Zhao ,&nbsp;Weipeng Yue ,&nbsp;Mao Hu ,&nbsp;Junqiang Niu ,&nbsp;Tiyuan Hou ,&nbsp;Yang Xu ,&nbsp;Hechuan Wang ,&nbsp;Shijie Wang ,&nbsp;Honghua Cao ,&nbsp;Youping Chen ,&nbsp;Heli Zhang ,&nbsp;Max C.A. Torbenson","doi":"10.1016/j.palaeo.2025.112898","DOIUrl":"10.1016/j.palaeo.2025.112898","url":null,"abstract":"<div><div>Global warming has emerged as a significant environmental challenge for humanity, particularly in climate-sensitive regions such as the Chinese Loess Plateau (CLP). Climate changes in this region are thought to have led to an increase in extreme weather events, adversely affecting ecosystems and agricultural development. This study uses spruce tree-ring samples to reconstruct precipitation data for the western CLP (WCLP) since 1598 CE. The resulting record accounts for 49 % of the variation in instrumental precipitation from July of the previous year to June of the current year. Through this reconstruction, we document occurrences of extreme drought and wet events over the past 426 years, record significant historical drought events in WCLP, reveal climatic driving mechanisms on different timescales, and analyze recent trends of increasing precipitation. This study contributes to a deeper understanding of the climatic history of the WCLP and provides scientific foundations for future climate predictions and regional sustainable development.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"668 ","pages":"Article 112898"},"PeriodicalIF":2.6,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143685359","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":"Meridional shifts of Brazil-Malvinas Confluence since the Last Glacial Maximum","authors":"Fang Gu ,&nbsp;Karin A.F. Zonneveld ,&nbsp;Hermann Behling","doi":"10.1016/j.palaeo.2025.112897","DOIUrl":"10.1016/j.palaeo.2025.112897","url":null,"abstract":"<div><div>The Brazil-Malvinas Confluence (BMC) is a highly dynamic convergence of surface currents in the southwestern South Atlantic, where the warm Brazil Current (BC) from the tropical Atlantic meets the cold Malvinas Current (MC) that originates from the northern branch of the Antarctic Circumpolar Current. Meridional shifts of the BMC play an important role in controlling the heat transfer from the tropical Atlantic to the higher latitudes of the South Atlantic. In this study, the marine core GeoB13861–1 is analyzed for pollen, spores, freshwater algae, and organic-walled dinoflagellate cysts (dinocysts) to reconstruct marine and terrestrial paleoenvironmental changes in southeastern South America since the Last Glacial Maximum (LGM). The results indicate that during LGM, the BMC was at its northernmost location due to the strong influence of the MC. During that period, exposed coastal areas of Argentina were dominated by salt marshes shaped by low global sea level. From ∼18 to 15 cal kyr BP, the BMC migrated southward, contributing to more humid conditions on the adjacent continent. As sea level rose, former salt marshes along the coast were gradually flooded. The increased presence of <em>Nothofagus</em> and <em>Podocarpus</em> pollen in the marine record suggests a slight expansion of Andean forests during the Late Glacial, indicating the adjacent continental regions shifted to wetter conditions. Notably, our study confirms that the signals of abrupt climate events, such as Heinrich Stadial 1 (HS1) and Younger Dryas (YD), are well-preserved in the marine sediment records. Our new findings provide clear evidence of the bi-polar sea saw effect during HS1, marked by abrupt ocean warming in the South Atlantic.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112897"},"PeriodicalIF":2.6,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643945","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":"The long-term dynamics of biodiversity and stability of the diatom community under climate warming in a Tibetan alpine lake","authors":"Yanjie Zhao ,&nbsp;Rong Wang ,&nbsp;Hengshuai Qiu ,&nbsp;Wenxiu Zheng ,&nbsp;Enlou Zhang ,&nbsp;Xiangdong Yang","doi":"10.1016/j.palaeo.2025.112882","DOIUrl":"10.1016/j.palaeo.2025.112882","url":null,"abstract":"<div><div>Remote lakes have been recognized as ideal monitors of global change as they are far from direct human intervention and can record the natural variabilities of lake ecosystems in their sediments. Over the past century, biodiversity losses and ecological regime shifts have been detected worldwide in the context of global warming. However, regions and biological communities are not studied equally in current research on biodiversity and stability, and high-elevation areas and aquatic micro-organisms are particularly underrepresented. This study explores Qudonglaco, an alpine lake above the treeline in the southeastern margin of the Tibetan Plateau, highlighting changes in its biodiversity and ecosystem stability in response to environmental drivers over the past two centuries. The study reconstructed terrestrial inputs from catchment and diatom community composition using paleolimnological proxies of geochemical elements and diatom assemblages, and calculated changes in species diversity and multifaceted stability over time. Under the impact of climate change, the lake environment changed dramatically after the 1990s, leading to a stark shift from tychoplanktonic-dominated to benthic-dominated community composition, accompanied by an almost doubling of species richness. Since 1975 CE, temporal stability has declined, with increased Jaccard similarity and network connectance, and reduced heterogeneity since the 1990s, signaling a decline in community resilience. Compared with the ecosystem development of arctic lakes between 1850 and 2000 CE, the 150-year beta diversity of diatom community in this region was smaller yet has continued to rise. The multidimensional changes of community stability and biodiversity should be considered when assessing the impacts of headwaters on the lower-reach ecosystems, and more monitoring and observation of remote ecosystems as well as a unifying framework for quantifying community stability from paleo-archives is needed.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112882"},"PeriodicalIF":2.6,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143619904","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":"Fossil vertebrates, biostratigraphy, biochronology and chronostratigraphy","authors":"Spencer G. Lucas","doi":"10.1016/j.palaeo.2025.112890","DOIUrl":"10.1016/j.palaeo.2025.112890","url":null,"abstract":"<div><div>Fossil vertebrates have been used to establish geological ages and correlations since the beginning of their scientific study by Georges Cuvier in the early 1800s. This work began with straightforward biostratigraphic analysis of vertebrate fossil distributions, and such analysis continues today. The North American land-mammal “ages,” first defined in 1941, represented the first explicit vertebrate biochronology. Since then, a biochronological approach has created much Phanerozoic biochronology in the form of land-mammal”ages,” land-vertebrate “ages” and land-vertebrate faunachrons. In marine settings, fossil fishes (especially Paleozoic ichthyoliths) have been employed in biostratigraphy. Paleozoic tetrapod fossils provide little useful chronology and correlation until the Middle Permian, when Pangea-wide tetrapod assemblages can be correlated based on some relatively cosmopolitan taxa and some locally abundant tetrapod assemblages. This continues through most of the Triassic, but, in Jurassic time provincialization of the tetrapod fauna and other factors have confounded attempts to develop useful vertebrate biostratigraphy and biochronology. The situation improves in the Cretaceous, when in some regions (especially the North American Western Interior basin) tetrapod fossils provide relatively detailed biostratigraphy and biochronology. Biochronological schemes using fossil mammals have proven to be particularly robust concepts used to divide Cenozoic time by land-mammal”ages.” Indeed, Cenozoic mammalian biochronology works so well in some regions (western USA) that little or no reference to the standard global chronostratigraphic scale below the level of epoch is made in age assignments and correlations. Land-mammal “ages” resolve time to about 1–3 million year intervals. They exemplify what can be achieved with vertebrate biochronology in terms of age determinations, correlations and placing vertebrate history into a broader framework of physical and biotic events. I thus advocate further development of such vertebrate biochronology for the entire fossil record of vertebrates. There also continues to be a need for more detailed stratigraphic data on vertebrate fossil distribution in order to refine current biochronological schemes, and I make some recommendations for future research.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112890"},"PeriodicalIF":2.6,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611594","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":"Climate-change induced human migration and socio-political changes in eastern India during the Meghalayan age","authors":"Dipanwita Sengupta ,&nbsp;Som Dutt ,&nbsp;Sophie F. Warken ,&nbsp;Arvinash Singam ,&nbsp;Norbert Frank ,&nbsp;Sumit Sagwal ,&nbsp;Sakshi Maurya","doi":"10.1016/j.palaeo.2025.112873","DOIUrl":"10.1016/j.palaeo.2025.112873","url":null,"abstract":"<div><div>The Holocene climate records, available from the Indian subcontinent are in fragments, majority having low temporal resolution and illustrate regional variability in proxy response. The impact of climate fluctuations on contemporary societies has been discussed in general. However, region specific climate-cultural linkages have not been adequately represented. This study presents a four-millennia-long time-series of Indian Summer Monsoon (ISM) variability from northeastern India using a U-Th dated stalagmite δ¹⁸O time series, particularly emphasising on the human development in eastern and northeastern India. The record exhibits ISM variability during ∼5.5 to ∼1.0 kyr BP. The results indicate weakened ISM conditions during 4.2–4.0 kyr BP and strong phases during 2.74–2.39 kyr BP and 1.42–0.97 kyr BP. The ISM fluctuations over the studied period had been significantly influenced by changes in the North Atlantic Oscillations (NAO), Intertropical Convergence Zone (ITCZ) latitudinal positioning and solar activity through teleconnections. Anthropological, historical and paleoclimatological evidences stitched together elucidate a story of climate induced human development in eastern and northeastern India. Signs of prosperous urban centres were evident in eastern India by ∼2.8 kyr BP and large kingdoms in this region established and rose to power between ∼1.3–0.9 kyr BP, mainly during the moderate to high ISM conditions.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112873"},"PeriodicalIF":2.6,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143629059","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":"The Middle–Late Pennsylvanian event: Timing and mechanisms","authors":"Yixin Wang,&nbsp;Keyi Hu,&nbsp;Xunyan Ye,&nbsp;Xiangdong Wang","doi":"10.1016/j.palaeo.2025.112893","DOIUrl":"10.1016/j.palaeo.2025.112893","url":null,"abstract":"<div><div>The Late Palaeozoic Ice Age (LPIA) was associated with climate fluctuations, significant biotic changes, the late Desmoinesian extinction, the conodont <em>Idiognathodus</em> diversification, and the “Carboniferous rainforest collapse”. These changes occurred in both marine and terrestrial realms during the Middle–Late Pennsylvanian, approximately 307–303.7 Ma. The timing, mechanisms, and magnitude of these events, especially the marine events, are poorly understood due to the scarcity of continuous Pennsylvanian successions and the challenges of international correlations caused by frequent glacio-eustatic transgressions and regressions during the LPIA. In southern Guizhou, South China, slope carbonate successions were deposited with abundant conodonts, providing opportunities to study these events. Based on materials from the Naqing, Shanglong, and Narao sections, conodont biostratigraphy, strontium and oxygen isotopes of conodont apatite, and carbon isotope of bulk rock across the Middle–Upper Pennsylvanian boundary interval are presented. Conodont zones, namely the late Moscovian <em>Idiognathodus podolskensis</em>, <em>Neognathodus roundyi,</em> and <em>Swadelina</em> sp. A zones, the Kasimovian <em>Sw</em>. <em>subexcelsa</em>, <em>Sw</em>. <em>makhlinae</em>, <em>I</em>. <em>heckeli</em>, <em>I</em>. <em>turbatus</em>, <em>I. magnificus</em>, “<em>I</em>.” <em>guizhouensis</em>, <em>Heckelina eudoraensis</em>, and “<em>I</em>.” <em>naraoensis</em> zones, and the Gzhelian <em>H. simulator</em> Zone are recognized. Focused on late Moscovian to early Kasimovian, three phases of environmental and biotic changes during the <em>Sw</em>. sp. A and <em>I. magnificus</em> zones are recognized. The first to second phases during the <em>Sw</em>. sp. A and <em>Sw</em>. <em>subexcelsa</em> zones are correlated with the dominance of rainforest biomes changing from cordaitaleans and lycopsids to marattialean trees. The second to the third phases during the <em>Sw</em>. <em>subexcelsa</em> and <em>I. magnificus</em> zones correlate with the late Desmoinesian extinction event, and radiation of <em>Idiognathodus</em> species. A general warming trend of ∼4–6 °C temperature rise calculated by δ¹⁸O could partly explain the aridification and collapse of rainforests. Changes in continental weathering were considered to partly drive the extinction and then radiation of conodonts during the middle–late Kasimovian supported by ⁸⁷Sr/⁸⁶Sr and δ¹⁸O of conodont apatite.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"667 ","pages":"Article 112893"},"PeriodicalIF":2.6,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143611593","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}