Palaeogeography, Palaeoclimatology, Palaeoecology最新文献

{"title":"Middle Cambrian large bivalved arthropods from Shandong, North China and their paleogeographic implications","authors":"Zhixin Sun,&nbsp;Han Zeng,&nbsp;Fangchen Zhao","doi":"10.1016/j.palaeo.2026.113594","DOIUrl":"10.1016/j.palaeo.2026.113594","url":null,"abstract":"<div><div>The large bivalved arthropods <em>Isoxys</em> and <em>Tuzoia</em> were widely distributed in Cambrian marine environments, occupying important evolutionary and ecological positions in early arthropod history. Here, we systematically studied middle Cambrian <em>Isoxys</em> and <em>Tuzoia</em> from four Burgess Shale-type Lagerstätten localities in the Mantou (Wuliuan) and Zhangxia (Drumian) formations of Shandong Province, North China. This study describes <em>I. shandongensis</em> Wang and Huang in <span><span>Wang et al., 2010</span></span>, <em>I. longissimus</em> <span><span>Simonetta and Delle Cave, 1975</span></span>, <em>T. manchuriensis</em> Resser and Endo in <span><span>Resser, 1929</span></span>, <em>T. guntheri</em> <span><span>Robison and Richards, 1981</span></span> and a new species <em>T. wudangshanensis</em> sp. nov. The large bivalved arthropod assemblage from the upper Panchegou Member of the Zhangxia Formation (upper Drumian) represents the latest fossil record of <em>Isoxys</em> and <em>Tuzoia</em> worldwide. The first occurrences of <em>I. longissimus</em> and <em>T. guntheri</em> outside of Laurentia extend the known spatial and temporal distribution of these taxa, suggesting a strong paleobiogeographic affinity between North China and Laurentia.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"687 ","pages":"Article 113594"},"PeriodicalIF":2.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081177","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":"Quantitative fluvial geomorphological constraints on differential activity of boundary faults and phased uplift of the Bogda Mountains in the northern Tian Shan, NW China","authors":"Jiaoyan Yang ,&nbsp;Dongli Zhang ,&nbsp;Qi Su ,&nbsp;Haiyun Bi ,&nbsp;Yige Li ,&nbsp;Fuer Yang ,&nbsp;Wenjun Zheng","doi":"10.1016/j.palaeo.2026.113570","DOIUrl":"10.1016/j.palaeo.2026.113570","url":null,"abstract":"<div><div>The Bogda Mountains, located in the middle-eastern section of the northern Tian Shan, are the forefront of its growth and expansion toward the Junggar Basin. Since the late Cenozoic (∼30 Ma), intense activity along piedmont faults has driven the rapid uplift of the Bogda Mountains and shaped the fluvial landscape. In this study, we used the bedrock channel stream-power erosion model and topographic analysis tools to extract 61 watersheds within the Bogda Mountains. Geomorphological parameters including the hypsometric integral (HI) and normalized steepness index (<em>kₛₙ</em>) were also calculated. Results indicate that the landscape of the Bogda Mountains is primarily controlled by three active faults. The Fukang fault is currently the most active, whereas the North Bogda fault has gradually weakened. The South Bogda fault may have experienced a period of tectonic reactivation. The analysis of χ and Gilbert metrics suggest respectively different results of drainage divide migration, indicating a tectonically controlled pattern of non-uniform uplift in the Bogda Mountains and the differential activity of the boundary faults. The drainage divide currently maintains a state of dynamic equilibrium. In this study, knickpoint response times were calculated through reconstructing paleo-channel profiles, concluding that the Bogda Mountains have undergone two significant tectonic uplift events at approximately 25–20 Ma and 5 Ma.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"687 ","pages":"Article 113570"},"PeriodicalIF":2.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080705","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":"Astronomical forcing of Late Triassic paleoclimate and paleohydrological fluctuations: insights from the Xujiahe Formation of the Sichuan Basin","authors":"Senxiuyuan Yu ,&nbsp;Fujie Jiang ,&nbsp;Yuqi Wu ,&nbsp;Lina Huo ,&nbsp;Yong Ma ,&nbsp;Benjian Zhang ,&nbsp;Gang Zhou","doi":"10.1016/j.palaeo.2026.113593","DOIUrl":"10.1016/j.palaeo.2026.113593","url":null,"abstract":"<div><div>The Late Triassic represents a pivotal transition in Earth system evolution. While marine strata preserve extensive records of Pangea breakup, Central Atlantic Magmatic Province (CAMP) emplacement, and biotic crises, interpreting global paleoenvironmental responses remains constrained by scarce terrestrial records from the eastern Tethyan margin. Here, we establish a high-resolution astronomical time scale (203.56–201.44 ± 0.57 Ma; duration: 2.12 Myr) using natural gamma-ray logging data from Well YQ1 in the Sichuan Basin. Integrated with isotopic and elemental geochemical proxies, this framework enables reconstruction of deep-time paleoclimatic and paleohydrological variations. Results reveal negative excursions in δ¹³C_V-PDB and δ¹⁸O_V-PDB, correlated with global carbon cycle perturbations triggered by CAMP. Geochemical proxies document a climatic transition towards colder and more arid conditions during the latest Triassic, accompanied by lake-level changes, salinity fluctuations, and productivity collapse. These paleoenvironmental fluctuations exhibit coherent phase relationships with 405-kyr and a potential ∼1.2-Myr astronomical cycle, identifying orbital forcing as a primary driver. Moreover, the superimposed of these orbital cycles amplified the CAMP-induced carbon cycle perturbation, triggering synchronous and abrupt shifts in regional paleoenvironmental and paleohydrological systems. Our findings provide insights from South China into terrestrial ecosystem responses to orbital forcing and global geological events during greenhouse climate states.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"687 ","pages":"Article 113593"},"PeriodicalIF":2.7,"publicationDate":"2026-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081178","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":"Evidence for endothermy from tooth enamel(oid) oxygen isotopes in marine predators of the Late Cretaceous Western Interior Seaway, USA","authors":"Chelsea M. Comans ,&nbsp;Thomas S. Tobin ,&nbsp;Rebecca L. Totten","doi":"10.1016/j.palaeo.2026.113578","DOIUrl":"10.1016/j.palaeo.2026.113578","url":null,"abstract":"<div><div>We analyze stable oxygen isotopes (δ¹⁸O_p) of tooth enamel(oid) from fossil marine predators from the Smoky Hill Chalk Member of the Niobrara Formation (Kansas, USA) to investigate the thermoregulatory modes of shark, bony fish, and mosasaur taxa that lived in the Western Interior Seaway (WIS) of North America during the Late Cretaceous. Through comparing these taxa with the co-occurring ectothermic bony fish †<em>Enchodus</em>, which serves as a proxy for ambient conditions, we assess the relative δ¹⁸O_p values of 21 individual organisms across nine genera, using data measured from 47 fossil teeth. The mosasaur taxa (†<em>Platecarpus</em> and †<em>Tylosaurus</em>) exhibit significantly lower δ¹⁸O_p values than †<em>Enchodus</em> that are consistent in the direction and magnitude expected for endothermy in this group. Most shark taxa, by contrast, are likely ectothermic because their δ¹⁸O_p values overlap with those of †<em>Enchodus</em>. The durophagous shark †<em>Ptychodus</em> and large predatory bony fish †<em>Xiphactinus</em>, however, record significantly lower δ¹⁸O_p values than <em>Enchodus</em> and other sharks, which we interpret as indicative of elevated body temperatures consistent with endothermy and migration. Comparison with the Gulf Coastal Plain (GCP) of North America reveals that †<em>Ptychodus,</em> †<em>Cretoxyrhina,</em> †<em>Platecarpus,</em> and †<em>Tylosaurus</em> have similarly low δ¹⁸O_p values across both regions. The consistency of δ¹⁸O_p value offsets for †<em>Ptychodus</em> across species and regions suggests that endothermy was a trait inherent to this genus. Differences in δ¹⁸O_p value offsets (from local †<em>Enchodus</em> values) between WIS and GCP for †<em>Tylosaurus</em> and †<em>Cretoxyrhina</em> may reflect differences in respective study sample size, methodology, and ecological factors, namely migration, and regional ecological differences and ontogenetic habitat partitioning within †<em>Cretoxyrhina</em>. Further, these new data support previous findings that †<em>Cretalamna</em> was ectothermic and †<em>Cretoxyrhina</em> was endothermic. The prevalence of endothermy in Late Cretaceous sharks is likely higher than previously thought, challenging hypotheses of endothermy evolution in Late Cretaceous sharks.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"687 ","pages":"Article 113578"},"PeriodicalIF":2.7,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026204","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":"Insights into the mechanisms behind Late Holocene climate variability in the northern tropics of South America based on modern climatic analyses","authors":"Maria I. Velez ,&nbsp;Juan Mauricio Bedoya-Soto ,&nbsp;German Poveda","doi":"10.1016/j.palaeo.2026.113586","DOIUrl":"10.1016/j.palaeo.2026.113586","url":null,"abstract":"<div><div>At the onset of the Meghalayan Age, 4200 years ago, Earth's global climate underwent significant changes as the Southern Hemisphere received more insolation. This led to changes in global atmospheric and oceanic circulation patterns resulting in reductions in precipitation and drought in some regions of the globe while creating wetter conditions in others. Although the start of the Meghalayan in tropical latitudes remain little discussed, two recent paleoenvironmental reconstructions from high-altitude sites in the Colombian Andes provide new insights on climate variability from the beginning of the Meghalayan until about 1300 years Before Present (yr BP). These records, along with comparisons to other Colombian paleo-archives, reveal a climatic divergence: between 4150 and 2500 yr BP, the Eastern Cordillera turned wet, and between 3700 and 1300 yr BP the Western Cordillera became dry. This contrasting pattern is opposite to modern conditions where the Eastern Cordillera is overall drier than the Western Cordillera. We explore potential drivers of this divergence focusing on the period between 4200 and 1300 yr BP, using modern precipitation data from rain gauges close to the paleo-sites, and regional rainfall estimates from the Climate Hazards Group InfraRed Precipitation (CHIRPS) dataset. Our approach included wavelet analyses, identification of moisture sources, and correlation analyses involving sea surface temperatures and various climatic indices. The results suggest that a simultaneous warming of the Tropical Pacific (TP) and the Tropical North Atlantic (TNA) would explain the increase in precipitation in the Eastern Cordillera and decrease in precipitation in the Western Cordillera, likely by an increase in the frequency and/or intensity of El Niño Southern Oscillation and/or Interdecadal Pacific Oscillation-like events.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"687 ","pages":"Article 113586"},"PeriodicalIF":2.7,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080707","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":"Molecular and bulk carbon isotope records in lacustrine sediments from the western Qaidam Basin, Northeast Tibetan Plateau, and implications for paleoenvironmental changes during the Eocene–Oligocene transition","authors":"Fan Yi ,&nbsp;Haisheng Yi ,&nbsp;Wenqiang Tang ,&nbsp;Yun Chen ,&nbsp;Kangzhi Tian ,&nbsp;Yuxiang Shi ,&nbsp;Xuemin Xu","doi":"10.1016/j.palaeo.2026.113588","DOIUrl":"10.1016/j.palaeo.2026.113588","url":null,"abstract":"<div><div>The climate and environment in inland Asia were regulated by and respond to the global cooling event at the Eocene–Oligocene transition (EOT) (ca. 33.8 Ma), during which time the Qaidam Basin (Northeast Tibetan Plateau) developed distinct hydroclimatic characteristics that differed from those in other regions. In this study, we examined organic carbon isotope (δ¹³C_org) and <em>n</em>-alkane carbon isotope (δ¹³C_{<em>n</em>-alkane}) records from lacustrine sediments deposited from the Late Eocene to Early Oligocene in deep drilling well A in the western Qaidam Basin. We investigated the regional climate and associated ecological and hydrological changes in the lake. The positive δ¹³C_org excursion of ∼2.3‰ recorded at the base of the Shangganchaigou Formation was correlated with the global Oi-1 event, which revealed synchronized carbon cycle perturbations in a terrestrial environment. The <em>n</em>-alkane indices and <span><math><msup><mi>δ</mi><mn>13</mn></msup><msub><mi>C</mi><mrow><mi>n</mi><mo>−</mo><msub><mi>C</mi><mn>17</mn></msub></mrow></msub></math></span>, <span><math><msup><mi>δ</mi><mn>13</mn></msup><msub><mi>C</mi><mrow><mi>n</mi><mo>−</mo><msub><mi>C</mi><mn>23</mn></msub></mrow></msub></math></span>, and <span><math><msup><mi>δ</mi><mn>13</mn></msup><msub><mi>C</mi><mrow><mi>n</mi><mo>−</mo><msub><mi>C</mi><mn>31</mn></msub></mrow></msub></math></span> values indicated the occurrence of a relatively arid climate in the Late Eocene. The lake system demonstrated moderate primary productivity, along with high salinity and a shallow chemocline, facilitating upward diffusion of ¹³C-depleted respired carbon dioxide into the photic zone and significantly affecting the isotopic composition of the dissolved inorganic carbon pool. The nearly 3‰ negative shift of <span><math><msup><mi>δ</mi><mn>13</mn></msup><msub><mi>C</mi><mrow><mi>n</mi><mo>−</mo><msub><mi>C</mi><mn>31</mn></msub></mrow></msub></math></span> and the positive δ¹³C_org excursion indicated the occurrence of increased precipitation in the western Qaidam Basin during the Early Oligocene. This humidification event triggered lacustrine expansion and nutrient dilution, which reduced the primary productivity and suppressing organic matter remineralization. The results of this study have highlighted the sensitivity of the Northeast Tibetan Plateau lakes to global climate forcing and provided a terrestrial benchmark for EOT paleoenvironmental models.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"687 ","pages":"Article 113588"},"PeriodicalIF":2.7,"publicationDate":"2026-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026203","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":"Regular and mechanism of millennial scale weak monsoon events during the late MIS7 to early MIS6.5 period","authors":"Shaohua Yang ,&nbsp;Shitao Chen ,&nbsp;Yongjin Wang ,&nbsp;Bin Zhao ,&nbsp;Yijia Liang ,&nbsp;Zhenjun Wang ,&nbsp;Zhenqiu Zhang ,&nbsp;Quan Wang ,&nbsp;Qingfeng Shao ,&nbsp;Lei Lu ,&nbsp;Chuan-Chou Shen","doi":"10.1016/j.palaeo.2026.113577","DOIUrl":"10.1016/j.palaeo.2026.113577","url":null,"abstract":"<div><div>Millennial-scale climatic variability during Marine Isotope Stage (MIS) 7.2 to 6.5, a period characterized by moderate global ice volume, remains poorly constrained due to limited high-resolution paleoclimate records. Here, we present a precisely dated, decade-resolution stalagmite oxygen isotope (δ¹⁸O) record from southern China, spanning 204.3 to 168.8 kyr BP and encompassing the late MIS 7.2 through early MIS 6.5 interval. Throughout this period, the Asian summer monsoon (ASM) closely tracked the insolation gradient between 30°N and 30°S on June 21 but was interrupted by eight distinct millennial-scale weak monsoon intervals (WMIs). These WMIs, centered at ∼169, ∼172.4, ∼174.6, ∼178.7, ∼180.4, ∼190.8, ∼195, and ∼ 203.4 kyr BP, align remarkably well with other high-resolution Chinese speleothem records, demonstrating widespread climatic instability despite moderate ice volume conditions. Significantly, a prominent hiatus lasting approximately 3300 years occurs at the depth of 282 mm within our stalagmite. This hiatus coincides precisely with a major WMI evident in other cave records and may be ascribed to an exceptionally weak Asian monsoon resulting in dramatically reduced stalagmite-forming precipitation. These WMIs are caused by ice drift debris (IRD) events caused by the rapid evolution of the ice sheet. Notably, our stalagmite record from the Asian monsoon region reveals a strong coupling with Antarctic temperature fluctuations via the bipolar seesaw mechanism, highlighting a significant influence of Southern Hemisphere climate dynamics on the ASM intensity. This observation further underscores the critical role of the inter-hemispheric insolation gradient in driving glacial/interglacial transitions. We tentatively propose that slowdowns in the Atlantic meridional overturning circulation (AMOC), triggered by freshwater fluxes into the North Atlantic, represent the primary forcing behind these abrupt climate events during MIS 7.2–6.5.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"687 ","pages":"Article 113577"},"PeriodicalIF":2.7,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146015898","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":"Pass on the grass? The unexpected “last supper” of hypselodont Pachyrukhinae (Notoungulata, Mammalia) from the late Neogene of northwestern Argentina","authors":"Matías Alberto Armella ,&nbsp;Darin Andrew Croft","doi":"10.1016/j.palaeo.2026.113585","DOIUrl":"10.1016/j.palaeo.2026.113585","url":null,"abstract":"<div><div>Hypsodonty and later hypselodonty (open-rooted/ever-growing teeth) have traditionally been associated with grazing habits in notoungulates (a group of South American native ungulates) and many other mammalian herbivore lineages. Recent evidence has challenged this paradigm, casting doubt on a simple correlation between hypselodonty and diet in notoungulates. We tested this proposal in pachyrukhines –small, rodent-like notoungulates with sciuromorph cranial adaptations and hypselodont dentitions– using low-magnification dental microwear analysis to reconstruct their diets. We used a comprehensive reference collection of 140 extant mammals spanning six dietary categories to develop a robust statistical framework integrating exploratory analyses, multivariate statistics, and three machine learning algorithms: Linear Discriminant Analysis (LDA), Support Vector Machines (SVM), and Random Forest (RF). The LDA performed best, with 70% overall accuracy and substantial agreement (κ = 0.62). We applied this model to 38 fossil specimens of <em>Tremacyllus</em> and <em>Paedotherium</em> from the Late Miocene to Pliocene of northwest Argentina. Against traditional expectations, 77% of <em>Tremacyllus incipiens</em> specimens were classified as fruit-seed consumers, with prediction probabilities exceeding 95% in most cases; the remaining individuals were classified as browsers, grass-leaf consumers, or grazers (all with low prediction probabilities). <em>Paedotherium</em> specimens were classified as either fruit-seed consumers or grazers. Our results suggest that pachyrukhines were mainly fruit-seed consumers rather than grazers, challenging long-standing dietary interpretations. Dietary variability likely reflects spatial and temporal heterogeneity in Neogene landscapes and perhaps seasonal resource partitioning. Our findings highlight the importance of testing morphological inferences with direct dietary proxies and reveal unexpected convergent ecological specialization in these rodent-like notoungulates.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"687 ","pages":"Article 113585"},"PeriodicalIF":2.7,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026205","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":"Asynchronous Holocene moisture and precipitation variability in the Tibetan Plateau monsoon-westerlies transition zone","authors":"Tianlong Yan ,&nbsp;Xiaomin Gao ,&nbsp;Ge Shi ,&nbsp;Chun Wang ,&nbsp;Junjiang Dong ,&nbsp;Qi Zhang ,&nbsp;Xiaoru Zhang ,&nbsp;Xiaoshuang Sun ,&nbsp;Jinliang Liu ,&nbsp;Can Zhang ,&nbsp;Cheng Zhao","doi":"10.1016/j.palaeo.2026.113583","DOIUrl":"10.1016/j.palaeo.2026.113583","url":null,"abstract":"<div><div>The monsoon-westerlies transition zone on the Tibetan Plateau (TP) is a sensitive climatic and ecological area influenced by both the Indian Summer Monsoon (ISM) and the mid-latitude westerlies. The driving mechanism of Holocene hydroclimatic change in this region remains debated. Here, we present a hydroclimatic reconstruction from the Hongyuan Peat based on multiple proxies, including the proportion of aquatic macrophytes (<em>P</em>_aq) from <em>n</em>-alkanes, the Methane Index (MI), Rb/Sr ratios, and organic matter content. The results show that moisture changes in the Holocene exhibited a tripartite “wet-dry-wet” pattern: (1) the early Holocene (12–7 ka BP) was the wettest stage, with high water tables mainly maintained by the strong ISM; (2) the middle Holocene (7–4.5 ka BP) experienced drying, reflecting reduced effective moisture; and (3) the late Holocene (after 4.5 ka BP) rewetted. However, there is a significant difference between this three-stage moisture evolution pattern and the trend of continuous reduction in regional precipitation. We interpret this pattern as the combined result of moisture distribution linked to the anti-phased influences of summer monsoon and winter westerlies, together with vegetation-evaporation feedbacks that modulate water storage and loss in peatland environments. These findings highlight the importance of circulation interactions and vegetation changes in shaping the Holocene hydroclimate pattern in the TP transition zone.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"687 ","pages":"Article 113583"},"PeriodicalIF":2.7,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026262","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":"Ostracod assemblages and their relationship with water depth in surface sediments of Nam Co, Tibetan Plateau","authors":"Tao Xu ,&nbsp;Yang Zhang ,&nbsp;Manping Xie ,&nbsp;Junbo Wang ,&nbsp;Huaxiu Hu ,&nbsp;Dingkuan Ge","doi":"10.1016/j.palaeo.2026.113584","DOIUrl":"10.1016/j.palaeo.2026.113584","url":null,"abstract":"<div><div>Quantitative reconstruction of lake-level changes at Nam Co is essential for the understanding long-term environmental evolution and climate dynamics of the Tibetan Plateau. Ostracod-based transfer functions for water depth serve as valuable tools for quantitative lake-level reconstructions. However, their reliability at Nam Co has been constrained by limited spatial and depth coverage, insufficient robustness testing, and weak cross-validation with independent regional proxies. To address these limitations, we integrated ostracod assemblages from multiple regions and applied comparative modeling to construct a more robust transfer function for Nam Co. This function was then used to reconstruct lake-level changes since the mid–late Holocene. Our results indicate that ostracod samples collected in different years exhibit no significant compositional differences, allowing their consolidation into a comprehensive lake-wide calibration dataset and improving model representativeness. Reconstructions generated through various statistical approaches revealed broadly consistent lake-level trends, supporting the robustness of the findings. By applying a random forest transfer function based on the integrated dataset, we quantitatively reconstructed the lake-level fluctuations at Nam Co since the mid–late Holocene. The reconstruction reveals a sequence of humid–arid phases followed by a return to humid conditions, closely aligned with other regional paleoclimatic records. These results demonstrate the strong applicability of the model to Nam Co. Further analysis suggests that these fluctuations were likely influenced by the combined effects of the Indian Summer Monsoon, glacial meltwater, and Westerly air masses.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"687 ","pages":"Article 113584"},"PeriodicalIF":2.7,"publicationDate":"2026-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081218","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}