Palaeogeography, Palaeoclimatology, Palaeoecology最新文献

{"title":"A Triassic semi-arid upland community of herbaceous ferns and rhizophagous arthropods evidenced by trace fossils in rhizogenic calcrete pedorelicts from SW England","authors":"Mark P. Howson,&nbsp;Maurice E. Tucker,&nbsp;Fiona F. Whitaker","doi":"10.1016/j.palaeo.2025.113221","DOIUrl":"10.1016/j.palaeo.2025.113221","url":null,"abstract":"<div><div>We present rare evidence of a Triassic upland biome. Pedorelicts (soil clasts) in continental sediments in SW England derived from a Middle-Upper Triassic semi-arid upland palaeoenvironment were studied using micro-CT scans and microscopy. They feature rhizogenic calcrete containing networks or mats of very fine roots that have been fossilized as rhizotubules, mostly 0.09–0.4 mm but up to 1 mm in diameter, with up to 4.7 m of rhizotubule length per cm³. Calcite dissolution and/or precipitation textures occur around the rhizotubules, and within them, calcite linings of 5–100 μm thick include calcified epidermal cells and in some of the thickest cases, cortical cells. We interpret these as evidence of a plant physiological process facilitating water and nutrient absorption in a semi-arid palaeoclimate. The size and both dichotomous and lateral branching of the rhizotubules, along with the interpreted palaeoecology, support identification of the producers as herbaceous calcicolous leptosporangiate ferns (<em>Polypodiidae</em>). Larger unlined tunnels of irregular 0.3–2 mm cross-section, some containing ovoid, spheroidal, clustered or irregular limonite grains, from 20 μm to over 100 μm in size, interpreted as coprolites, traverse the rhizotubule networks. These are attributed to burrowing rhizophagous arthropods with mandibles and/or other means sufficient to breach some calcified rhizotubules. They also provided sites for later root growth. These pedorelicts host rare trace fossil evidence of an upland community of plants and animals with roles in pedogenesis during significant intervals of geomorphic stability between major pluvial reworking events.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"678 ","pages":"Article 113221"},"PeriodicalIF":2.7,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144933519","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":"Earliest Triassic microbial mounds indicate an ‘oasis’ for recovery of life following the end-Permian extinction","authors":"Dan Qiao ,&nbsp;Zhiqiang Shi ,&nbsp;Jiangong Wang ,&nbsp;Kui Wu ,&nbsp;Shenyuan Peng ,&nbsp;Michael J. Benton","doi":"10.1016/j.palaeo.2025.113216","DOIUrl":"10.1016/j.palaeo.2025.113216","url":null,"abstract":"<div><div>Metazoan assemblages are rare in Early Triassic successions because of stressful environments in shallow seas after the end-Permian mass extinction (EPME). There is active debate about whether life in the oceans recovered rapidly or was delayed by up to 6–7 Myr. Here we present a new seabed assemblage showing evidence for relatively diverse animals in the middle Griesbachian, less than 1 Myr after the EPME crisis. The fossils are in microbial mounds from Chongqing, in the Upper Yangtze region, SW China, primarily composed of calcified filamentous cyanobacteria, including <em>Cyanonema</em>, Rivulariaceae, and Girvanellaceae, as well as planktonic calcareous microorganisms (calicispheres). The animals of the microbial mound include relatively common microconchids, sponges, gastropods and bivalves, and less abundant echinoderms and brachiopods. These metazoan communities differ among sub-facies of the microbial mound deposits, implying diverse ecosystem structures during the growth phase of the mounds. This kind of microbial mound might not only be typical of the aftermath of the mass extinction, but also have served as an ‘oasis’ for animals in the otherwise inhospitable environments of the Early Triassic seas.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"677 ","pages":"Article 113216"},"PeriodicalIF":2.7,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144890830","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":"Paleo-ocean chemistry characteristics of the Cryogenian Datangpo Formation in South China and implications for manganese metallogenesis","authors":"Zhixin Ma ,&nbsp;Yun Ling ,&nbsp;Yongjun Qin ,&nbsp;Yu Liu ,&nbsp;Xicai Yao ,&nbsp;Ping Wang ,&nbsp;Xiting Liu","doi":"10.1016/j.palaeo.2025.113212","DOIUrl":"10.1016/j.palaeo.2025.113212","url":null,"abstract":"<div><div>Paleo-ocean chemical variations play a critical role in understanding the genesis of manganese (Mn) ore deposits within the Cryogenian Datangpo Formation of South China. Based on lithological observations and multiple geochemical proxies—including iron speciation, molybdenum (Mo), uranium (U), vanadium (V), manganese (Mn) concentrations, Sr/Ba ratios, the Chemical Index of Alteration (CIA), and pyrite sulfur isotopes (δ³⁴S_py)—from drill core ZK0602 in Chongqing, South China, the lower black shales of the Datangpo Formation were deposited under euxinic fresh-brackish water conditions and can be subdivided into four intervals (Intervals I, II, III, and IV). Notably, relatively high Mn concentrations and metallogenesis are genetically linked to ferruginous marine conditions in interval II, which is sandwiched between two euxinic fresh-brackish intervals (I and III). An updated conceptual framework is proposed to decipher the co-evolutionary dynamics among redox condition, salinity fluctuations, and manganese metallogenesis. During intervals I and III, Sturtian deglaciation-driven warming enhanced chemical weathering, increasing terrigenous input to the basin and reducing water-column salinity. Concurrently, elevated nutrient inputs from both open-ocean and terrigenous sources heightened surface-water primary productivity and subsequent anaerobic organic matter mineralization in the water column, inducing bottom-water sulfidization and promoting pyrite formation. In contrast, during interval II, as glacial stadials emerged within the interglacial period, chemical weathering weakened, terrigenous input decreased, and the salinity of the basin water body rose to marine levels. Diminished nutrient supplies from both oceanic and terrestrial sources decreased primary productivity, reducing the downward flux of organic matter and sulfate. This shift favored manganese reduction as the dominant organic matter oxidation pathway. Under ferruginous conditions, Mn ore precipitated near the water–sediment interface.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"677 ","pages":"Article 113212"},"PeriodicalIF":2.7,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144890843","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":"Major Late Pleistocene explosive eruptions of Changbaishan and Japanese volcanoes revealed by a 100-ka tephra record from the Sea of Japan","authors":"Jia Chen ,&nbsp;Chunqing Sun ,&nbsp;Yang Li ,&nbsp;Yuxin Chen ,&nbsp;Shuang Zhang ,&nbsp;Zhengfu Guo ,&nbsp;Jiaqi Liu","doi":"10.1016/j.palaeo.2025.113219","DOIUrl":"10.1016/j.palaeo.2025.113219","url":null,"abstract":"<div><div>The many subaerial volcanoes around northeast Asia have experienced frequent large- magnitude eruptions. However, many of them are not fully characterized geochronologically and geochemically, such as Changbaishan on the border between China and North Korea. We identified ten tephra layers in marine sediment cores from the Sea of Japan, confirming the occurrence of seven major eruptions around northeast Asia over the past 100 ka. Three of the tephra layers are major marker horizons around northeast Asia: AT (∼30 ka), Aso-4 (∼86 ka), and Toya (∼108 ka), which were used to constrain age models of the sediment cores. A pre-AT tephra, possibly correlative with the A-Kn eruption of the Aira caldera, was recognized in the central Sea of Japan, and it is linked to the high-resolution sedimentary record of Lake Suigetsu. The fourth Aso-4 component was recognized in this study, while component 3 was not recognized in the sediment cores from the Sea of Japan, suggesting that the eruption and tephra dispersal processes of the ∼86 ka Aso-4 eruption were complex. Additionally, one tephra layer with the age of 92.0–86.1 ka was identified in the eastern Sea of Japan; it had a similar composition to the BT-30 tephra recorded in Lake Biwa, indicating that it can serve as a new marker horizon from the Sea of Japan to central Japan. For the first time, the Changbaishan Tianwenfeng eruption was correlated with the B-J tephra from the Sea of Japan, based on a robust geochemical correlation between distal and proximal records, and was dated to 60.1–47.3/53.8–42.7 ka based on the age models of the marine sediment cores. The B-Ym tephra with an age of 87.3–81.8 ka recorded in the eastern Sea of Japan was correlated to the Changbaishan tephra, but the source eruption was not determined. These two tephra layers could be used as potential regional marker horizons when considering their thickness present in the marine sediments of the Sea of Japan.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"677 ","pages":"Article 113219"},"PeriodicalIF":2.7,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144892299","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":"Cryogenian provenance and tectonic setting evolution of South Qinling Belt: Insights from detrital zircon UPb geochronology and LuHf isotope analysis","authors":"Jie Gao ,&nbsp;Hanyu Huang ,&nbsp;Dengfa He ,&nbsp;Di Li ,&nbsp;Chao Fu ,&nbsp;Anqing Chen ,&nbsp;Jie Hu ,&nbsp;Yanhua Xu ,&nbsp;Guo Lu","doi":"10.1016/j.palaeo.2025.113210","DOIUrl":"10.1016/j.palaeo.2025.113210","url":null,"abstract":"<div><div>Significant uncertainties persist regarding the depositional environment, tectonic affinity, and geodynamic significance of the extensively exposed Neoproterozoic Yaolinghe Group rocks in the South Qinling Belt (SQB) and the northern margin of Yangtze Block (NYZB), hindering the interpretation of their sedimentary record, regional tectonic evolution, and role in Rodinia assembly-breakup dynamics. This study conducted comprehensive investigations on sedimentary rocks in both the Zhenping and Langao areas. By utilizing LA-ICP-MS zircon U<img>Pb isotope analysis and integrating previous data, our findings indicate that these sedimentary rock<u>s</u> were deposited during the early to middle Cryogenian period. Lu<img>Hf isotope analysis reveals a wide range of ε_Hf(t) values for sample ZP-4, ranging from −17.22 to 10.47 with an average of −4.7, indicating reworked ancient crust as their source material. Sample LG-6 from Langao exhibits a range of ε_Hf(t) values, ranging from −18.56 to 11.18, with an average value of −2.7; a subset of younger detrital zircons (&lt;750 Ma) displays positive ε_Hf(t) values, suggesting the incorporation of material eroded from juvenile crust. Furthermore, the presence of sedimentary rock fragments within the Yaolinghe Group deposits suggests the exhumation and subsequent redeposition of ancient sedimentary sequences, such as the Wudang Group, Nantuo Formation, and Liantuo and Gucheng Formations, took place along the northern margin of the Yangtze Block and South Qinling Belt. Notably, the Zhenping area lies within an intracontinental rift zone. In contrast, the Langao area in the SQB appears to have been closer to the outer continental margin and significantly influenced by adjacent sources, including early or contemporaneous magmatic zones. In conjunction with regional data, we propose that the SQB transitioned from early subduction accretion to late-stage extensional rifting during the Cryogenian. This sequence of events may represent the response of the marginal blocks of the Rodinia supercontinent to the final rifting during the Middle to Late Neoproterozoic.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"678 ","pages":"Article 113210"},"PeriodicalIF":2.7,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896690","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":"Controls on carbon isotopes during the upwelling system development in shallow marine environments: Regional evolution in the Roadian (Mid-Permian) of South China","authors":"Han Lei ,&nbsp;Wenhui Huang ,&nbsp;Qingchun Jiang ,&nbsp;Ping Luo","doi":"10.1016/j.palaeo.2025.113215","DOIUrl":"10.1016/j.palaeo.2025.113215","url":null,"abstract":"<div><div>Throughout geological time, upwelling systems have been widespread in shallow marine environments. However, the regional carbon cycle in shallow marine environments during the development of upwelling systems remains unclear. During the middle Permian, astronomically forced upwelling systems were widespread along the west coast of Pangaea and the paleoequator. This study focuses on the astronomical-forced middle Permian (Roadian) rhythmites from the South China continental shelf and carbonate platform to explore the evolution of carbon isotope control factors in shallow marine environments during upwelling system development. Based on geochemical characteristics, time series analyses, and wavelet coherence analyses, the Roadian stage was subdivided into three phases in upwelling system evolution. As the system developed, the continental shelf became oxygen-depleted, warm–humid, and highly weathered, whereas the carbonate platform remained relatively stable. First, the initial development stage. The δ¹³C_org on the continental shelf and the δ¹³C_carb in the carbonate platform averaged −25.67 ± 0.57 ‰ and 3.61 ± 0.25 ‰, respectively. Carbon isotopes in shallow marine environments were primarily controlled by paleoclimate fluctuations (and the upwelling effect). The relatively cool–dry climate weakened continental weathering, upwelling, and organic carbon burial on the continental shelf. However, these conditions also lowered sea levels and restricted water exchange in the carbonate platform, leading to ¹²C depletion. Next, with the intensification of upwelling, its influence on intra-platform carbon isotopes surpassed paleoclimates, with δ¹³C_carb remaining stable at 3.86 ± 0.39 ‰. The influx of upwelling during sea-level rise promoted organic carbon burial and a positive shift in δ¹³C_carb. On the continental shelf, nevertheless, δ¹³C_org values decreased slightly to −25.98 ± 0.61 ‰. The rapid expansion of the oxygen minimum zone reduced sulfate concentrations, facilitating reverse reactions of the anaerobic oxidation of methane and thereby highlighting the control of sulfate reduction reactions on δ¹³C. Simultaneously, TS and Fe_py contents declined, along with siderite and pyrite deposition. Finally, during the complete development stage, the δ¹³C_carb values in the carbonate platform stabilized at 3.77 ± 0.45 ‰, while the δ¹³C_org declined to −26.93 ± 0.39 ‰. The upwelling intensity and redox conditions gained dominance over δ¹³C by promoting organic carbon burial in shallow marine environments.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"677 ","pages":"Article 113215"},"PeriodicalIF":2.7,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144892917","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":"Lake shoreline identification and water storage change estimation of the largest lacustrine period from Marine Isotope Stage 5 to Holocene on the Tibetan Plateau","authors":"Yuqi Zhang ,&nbsp;Xiangjun Liu ,&nbsp;Baojin Qiao","doi":"10.1016/j.palaeo.2025.113169","DOIUrl":"10.1016/j.palaeo.2025.113169","url":null,"abstract":"<div><div>There are numerous lakes on the Tibetan Plateau (TP), which constitutes a significant part of the ”Water Tower of Asia”, and multiple high lake levels occurred during historical periods. However, current researches primarily focus on field investigations and dating of shorelines for individual or a few lakes. This study emphasized the identification of highest lake shorelines across the entire TP, along with a study of the extent and water storage variations of the largest lakes during Marine Isotope Stage 5 to Holocene, which is conducive to understand the characteristics of lake change in the past and facilitating more accurate prediction of future lake variation. In this study, we identified the highest lake shorelines on the TP by Google Earth, and reconstructed the water storage change since the largest paleo-lake during the geological historical period relative to current lake in 2022. Finally, we found that 181 lakes were merged into 115 lakes in the past period. The results showed that the total area of the lakes during the largest lacustrine period was 60 675<!--> <!-->km², which was nearly twice as large as the modern lakes, and the average water level was 43<!--> <!-->m higher than that of the modern, with the water storage change of 2681<!--> <!-->km³, which was 3 times of the modern. The lakes with large changes were mainly distributed in the southern and western parts of TP. The water storage change in the combined lake group was 1994<!--> <!-->km³, accounting for 74.38% of the total change. Combined with the age data of 32 lakes, it showed that the ages of the highest water level of lakes mostly occurred in Holocene, the Last Deglaciation and the Marine Isotope Stage (MIS) 3. This study will be helpful to understand the spatial differences of paleo-lake changes and its evolution mechanism.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"677 ","pages":"Article 113169"},"PeriodicalIF":2.7,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144867359","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":"Cretaceous (Maastrichtian) Vertisols of the Serra da Galga Member (Bauru Basin, Brazil): Implications for palaeoclimate and palaeoecology","authors":"Vithor Di Donato ,&nbsp;Maurícius Nascimento Menezes ,&nbsp;Patrick Führ Dal' Bó ,&nbsp;Daniel Sedorko ,&nbsp;Jon J. Smith ,&nbsp;Leonardo Borghi","doi":"10.1016/j.palaeo.2025.113214","DOIUrl":"10.1016/j.palaeo.2025.113214","url":null,"abstract":"<div><div>In this paper, we report the occurrence of Cretaceous (Maastrichtian) Vertisols from three profiles in the Serra da Galga Member (Marília Formation) of the Bauru Basin, Brazil, which developed as distributary fluvial deposits. Through integrated analysis of macroscopic and microscopic pedogenic features, clay mineralogy, whole-rock geochemistry, and ichnofossil assemblages, we assess the roles of climate, biota, and topography in shaping pedogenesis and organismal behavior under seasonal climatic regimes. The primary pedogenic processes identified include argiliturbation, clay translocation, calcification, and biological activity. Paleoclimatic reconstructions indicate mean annual precipitation ranging from 290 to 614 mm/year (mean: 504 ± 33 mm/year) and mean annual temperature between 10.6 °C and 12.2 °C (mean: 11.4 ± 0.62 °C). Köppen-based aridity indices suggest that all soil horizons formed under semiarid to subhumid conditions. The ichnoassemblages include invertebrate traces (<em>Taenidium, Skolithos,</em> and <em>Beaconites</em>) and plant-related structures (calcareous rhizoconcretions, rhizohalos, and calcified bulbilous structures), exhibiting low to moderate bioturbation degree. The correlation between ichnofossil distribution, bioturbation intensity, geochemical data, and pedogenic characteristics suggests that the Vertisols developed under distinct seasonal climatic conditions. These soils displayed moderate drainage, characterized by short-term rises in the water table within the floodplain, followed by prolonged dry periods. Soil moisture availability played a crucial role in regulating biotic activity throughout these seasonal fluctuations. The results obtained not only enhance the understanding of pedogenetic and paleoecological processes during the Maastrichtian in the Bauru Basin but also provide a model for interpreting Vertisol formation in semiarid environments at mid-latitudes. Furthermore, they may provide a useful basis for global paleoclimate reconstructions.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"677 ","pages":"Article 113214"},"PeriodicalIF":2.7,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144887308","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":"High-resolution carbon-isotope stratigraphy of the Cambrian Series 2–Miaolingian Series in Upper Yangtze Platform, South China: Implications for global correlation","authors":"Huachuan Jiang ,&nbsp;Jintong Liang ,&nbsp;Karem Azmy ,&nbsp;Yan Wei ,&nbsp;Lian Duan ,&nbsp;Hao Zhang ,&nbsp;Taiyuan Fan ,&nbsp;Jian Xu ,&nbsp;Wei Zheng ,&nbsp;Huaguo Wen","doi":"10.1016/j.palaeo.2025.113213","DOIUrl":"10.1016/j.palaeo.2025.113213","url":null,"abstract":"<div><div>The Redlichiid-Olenellid extinction carbon-isotope excursion (ROECE) and Drumian carbon-isotope excursion (DICE) represent two pronounced negative C-isotope excursion events in the lower to middle Cambrian and have been proposed as key chemostratigraphic markers for identifying the Cambrian Stage 4–Wuliuian Stage boundary and the base of the Drumian Stage, respectively. However, the precise local and global correlations of the ROECE and DICE remain unsolved, and the heterogeneity of their magnitudes is controversial. In the current study, we report a new high-resolution δ¹³C_carb profile from the Zhangfeiqian (ZFQ), Shiliu (SL), and Qiliao (QL) sections in the Upper Yangtze Platform (South China) that spans the Cambrian Stage 4-Jiangshanian Stage. The investigated Shilongdong, Gaotai, and Xixiangchi formations are dominated by lime mudstone and dolomicrite, occasionally alternating with thinly-bedded mudstone or sandy dolomite interbeds. The preservation of the investigated carbonates was meticulously evaluated by multi-screening petrographic and geochemical techniques. The δ¹³C_carb values (−0.5 ± 1.2 ‰ VPDB) exhibit an insignificant correlation with their δ¹⁸O_carb (−8.8 ± 1.6 ‰ VPDB, R² = 0.01) and Mn/Sr ratios (R² = 0.18), which supports the preservation of at least near-primary δ¹³C signatures that can be utilized to construct a reliable high-resolution δ¹³C profile for global correlations. The δ¹³C_carb profile shows two main negative excursions, the lower excursion (∼ 6.0 ‰) almost at the middle part of the Gaotai Formation and the upper excursion (∼ 3.2 ‰) at the lower part of the Xixiangchi Formation. The trilobite biozonation scheme supports the correlation of the lower excursion with the ROECE and the upper excursion with the DICE events, which have been globally documented on different paleocontinents. Combined with previous studies, we provide a continuous high-resolution δ¹³C_carb profile of the Cambrian in the Yangtze Platform for global chemostratigraphic correlations.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"678 ","pages":"Article 113213"},"PeriodicalIF":2.7,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144896689","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":"Environmental changes in the South-Iberian Palaeomargin from the latest Pliensbachian to middle Toarcian (Early Jurassic) based on mineralogical data and geochemical proxies","authors":"Chaima Ayadi ,&nbsp;Isabel Abad ,&nbsp;Elisa Laita ,&nbsp;Emanuela Mattioli ,&nbsp;Matías Reolid","doi":"10.1016/j.palaeo.2025.113191","DOIUrl":"10.1016/j.palaeo.2025.113191","url":null,"abstract":"<div><div>The Arroyo Mingarrón section from the Median Subbetic (Betic Cordillera, South Spain) consists of hemipelagic sediments, including marls, limestones, and condensed limestones of the uppermost Pliensbachian to middle Toarcian (NJT5a to NJT7c nannofossil subzones). Mineralogical and geochemical analyses suggest that environmental conditions in this part of the Western Tethys were predominantly arid. The dominance of illite and quartz indicates physical weathering and arid conditions in the emerged lands surrounding the South-Iberian Palaeomargin.</div><div>This section includes the negative carbon isotopic excursion (CIE) that characterizes the Jenkyns Event located in the boundary between NJT5 and NJT6 zones. In Arroyo Mingarrón section, the Jenkyns Event is characterized by a decrease in carbonate content and enhanced detrital input of siliciclastics. The decrease in carbonate productivity during the event is evidenced by changes in the composition of the calcareous nannofossil assemblages with abundance and diversity decrease, as well as reduced size of <em>Schizosphaerella</em>. Anoxic conditions were not developed at the sea bottom considering the record of trace fossils and microfossils at the base of the NJT6 Zone, as well as the low total organic carbon (&lt; 0.3 wt%). High proportions of illite, the decrease in plagioclase index of alteration (PIA) and the increase in index of compositional variability (ICV) indicate relatively more arid conditions during the Jenkyns Event. The lower part of the middle Toarcian shows the evolution of the studied sector from a subsident area to a pelagic swell with increasing carbonate content and progressively more condensed facies toward the top. The record of kaolinite and increased values of weathering proxies (CIA and PIA) and the fluvial detrital proxy K/Al points to a relative increase in humidity and weathering. The development of the pelagic swell in the upper part of the middle Toarcian is parallel to a return to enhanced dry climatic conditions as indicated by the decrease in clay content with the absence of kaolinite, the decrease of in fluvial detrital proxy K/Al, and the decrease in weathering proxies (PIA and C-value).</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"678 ","pages":"Article 113191"},"PeriodicalIF":2.7,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144912325","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}