Palaeogeography, Palaeoclimatology, Palaeoecology最新文献

{"title":"Dinoflagellate cyst and vegetational dynamics during the Early Jurassic (late Pliensbachian–early Toarcian) in Tibet","authors":"Changjun Ji ,&nbsp;Ahmed Mansour ,&nbsp;Zhenhan Wu ,&nbsp;James B. Riding ,&nbsp;Yun Chen ,&nbsp;Qian Wang","doi":"10.1016/j.palaeo.2025.113500","DOIUrl":"10.1016/j.palaeo.2025.113500","url":null,"abstract":"<div><div>The late Pliensbachian–early Toarcian (Early Jurassic) marks a critical interval in Earth history, characterised by major palaeoclimatic, palaeoenvironmental, and palaeoceanographical perturbations. This study examines the Pliensbachian–Toarcian Quse Formation at the Qixiangcuo section in the Southern Qiangtang Basin (Tibet), using palynological analysis to investigate dinoflagellate cyst evolutionary patterns and vegetation dynamics prior to and during the Jenkyns Event. Palynological data showed a clear record of late Pliensbachian dinoflagellate cyst radiation, likely owing to cooler climatic and enhanced water mass circulation between the Arctic-Boreal and Tethyan realms. Prior to the Jenkyns Event, a dinoflagellate cyst acme is observed, possibly controlled by sea-level rise, increased seawater salinity, and well-ventilated conditions. During the Jenkyns Event, a blackout event of dinoflagellate cysts occurred in the Southern Qiangtang Basin, consistent with records from the central Tethys and Boreal regions, likely triggered by global warming and rising seawater temperatures. Pollen assemblages across the Pliensbachian-Toarcian transition are dominated by Cheirolepidiaceae conifers (<em>Classopollis</em>), compared to reduced cycadophytes, bennettites, and ginkgophytes, and sparse fern spores. This reflects a vegetation turnover towards xerophytic, drought-tolerant vegetation in arid lowland environments, likely linked to the initial phase of Karoo-Ferrar volcanism. During the Jenkyns Event, Cheirolepid coniferous pollen remained dominant before temporarily disappearing, indicating a demise of mixed wet mire-conifer communities and a shift towards drought-adapted flora. Similar patterns of deforestation and vegetation crisis are observed across the Tethys and Boreal realms, contemporaneous with the main phase of the Karoo-Ferrar volcanism and rising atmospheric CO₂. Regional comparisons of vegetation response across the Jenkyns Event reflect different magnitudes of predominance and recovery patterns in Cheirolepid conifers.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113500"},"PeriodicalIF":2.7,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799354","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":"Taiwan's land-vertebrate suite: An assemblage forged by tectonism and sea-level shifts","authors":"Jason R. Ali ,&nbsp;Uwe Fritz","doi":"10.1016/j.palaeo.2025.113502","DOIUrl":"10.1016/j.palaeo.2025.113502","url":null,"abstract":"<div><div>Like many islands in continental-shelf settings, Taiwan has a rich land-vertebrate suite comprising mainly nonendemic taxa. Unusually, though, it also hosts a substantial fraction of endemic species, some the result of in situ diversification. Here, we disentangle the physical processes that have shaped the island's assemblage and document the roles they played. Taiwan is a high-elevation landmass on the edge of China's continental shelf, its emergence resulting from the ongoing collision between the Eurasian and Philippine Sea Plates, which started <em>c</em>. 5 Mya. For the first <em>c</em>. 4 Myr of the island's history colonizations involved over-water dispersal, hence relatively few establishment events. Significantly, the sizeable ecospace the incomers entered hosted a variety of niches (notably, greater than those in the areas they crossed from), and this spurred anagenesis and occasionally cladogenesis. Although the Pleistocene sea-level falls (starting <em>c</em>. 2.6 Mya) modified greatly and frequently the regional geography, only those occurring after 900 kya were sufficiently large (i.e., below −72/−75 m) to open up a succession of landbridges across the Taiwan Strait seabed to mainland Asia. Significantly, such episodes allowed taxa to enter Taiwan unimpeded, thereby accounting for the bulk of its lineages, most of which are nonendemic.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113502"},"PeriodicalIF":2.7,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885191","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":"Vegetation responses to the mid-Holocene abrupt climate events in the Forest-Steppe Ecotone in northern China","authors":"Yao Zhang ,&nbsp;Lili Niu ,&nbsp;Qiaoyu Cui ,&nbsp;Yi Lin ,&nbsp;Zhiping Zhang ,&nbsp;Jiaju Zhao ,&nbsp;Xinwei Yan ,&nbsp;Aifeng Zhou","doi":"10.1016/j.palaeo.2025.113506","DOIUrl":"10.1016/j.palaeo.2025.113506","url":null,"abstract":"<div><div>Vegetation ecosystems in the East Asian monsoon margin in northern China are highly sensitive and ecologically vulnerable. Understanding long-term vegetation dynamics and their responses to abrupt climate events is critical for guiding ecological conservation and sustainable land-use planning. In this study, we reconstructed vegetation dynamics using a high-resolution pollen record from the Qixing peatland in the Saihanba region. Results indicated that climate was the primary driver of vegetation changes, while temperature and precipitation variations were asynchronous. The mid-Holocene was characterized by maximum precipitation; however, an abrupt cooling event between 7000 and 5500 cal yr BP triggered a rapid decline in deciduous broadleaf trees alongside a concurrent expansion of herbaceous vegetation, ultimately leading to steppe-dominated ecosystems. This transition was accompanied by reduced vegetation diversity and increased spatial heterogeneity. Subsequently, coniferous forests dominated by <em>Pinus</em>, as a major component of the secondary vegetation, became prevalent. However, a sudden shift to aridity around 5000 cal yr BP associated with the weakening of the East Asian summer monsoon prompted a rapid spread of herbs, along with a recovery in diversity and evenness. This study demonstrates that abrupt climate shifts caused forest retreat and grassland expansion once critical climatic thresholds were exceeded across the monsoon marginal zone. Given the current context of accelerated climate warming and increasingly frequent extreme climatic events, urgent protective measures are essential for these highly vulnerable ecosystems.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113506"},"PeriodicalIF":2.7,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedimentary facies and invertebrate faunal exchange confirm humid conditions in the tropical eastern Atlantic during interglacial Marine Isotopic Stage (MIS) 11c","authors":"Carlos S. Melo ,&nbsp;José Madeira ,&nbsp;Ricardo S. Ramalho ,&nbsp;Ana C. Rebelo ,&nbsp;Michael W. Rasser ,&nbsp;Esther Martín-González ,&nbsp;Alfred Uchman ,&nbsp;Carlos Marques da Silva ,&nbsp;Emílio Rolán ,&nbsp;Luís Silva ,&nbsp;Joseph A. Stewart ,&nbsp;Laura F. Robinson ,&nbsp;Deirdre D. Ryan ,&nbsp;Alessio Rovere ,&nbsp;Antje Voelker ,&nbsp;Patrícia Madeira ,&nbsp;Mário Cachão ,&nbsp;Sérgio P. Ávila","doi":"10.1016/j.palaeo.2025.113505","DOIUrl":"10.1016/j.palaeo.2025.113505","url":null,"abstract":"<div><div>The geological study of Marine Isotopic Stage (MIS) 11c (424–397 ka) is key to reconstructing the climatic and oceanographic conditions during one of the longest and the warmest interglacial in the last 1 million years. Moreover, interglacial MIS 11c is considered as an important analogue for our near future in times of climate change, under anthropogenic emissions scenarios, due to its similar orbital forcing configuration. Here we present the results of a comprehensive analysis of one of the most extensive Quaternary fossiliferous sedimentary successions in the Cabo Verde archipelago in the tropical northeastern Atlantic. The Nossa Senhora da Luz Bay (Santiago Island) is one of the few MIS 11 fossiliferous sites known in Macaronesia. The sedimentary succession records a set of transitions between fluvial and marine environments, and emersion and immersion events within a confined, highly protected bay environment. A thick layer of fine-branched rhodoliths in its upper part suggests ecological conditions that no longer exist in Cabo Verde. The presence of specimens of the intertidal clam <em>Senilia senilis</em> in life position ∼12 m above present-day mean sea level leads us to reinterpret the relative sea-level changes at Santiago Island and show that the uplift trend since MIS 11c is an order of magnitude lower (0.01 mm/yr) than previously calculated (0.10 to 0.14 mm/yr). The fossil assemblage includes representatives of five phyla, with molluscs being the most diverse and abundant. Despite the abundance of some bivalves (<em>Saccostrea cuccullata</em>, <em>S. senilis</em>, and <em>Aequipecten opercularis</em>), and gastropods (<em>Thetystrombus latus</em> and <em>Thais nodosa</em>), and some horizons showing the crustacean burrows <em>Thalassinoides suevicus</em>, the general biodiversity is low. The presence of <em>S. cuccullata</em> and <em>S. senilis</em>, both absent from present-day Cabo Verde archipelago, indicates a tropical, more humid climate in this region, during MIS 11c.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113505"},"PeriodicalIF":2.7,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885192","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":"Decoupled intracontinental convergence between the South Tian Shan and northern Tarim Basin since the Neogene: Constraints from stratigraphy and detrital zircon UPb geochronology of the Alparlek section","authors":"Kaixuan An ,&nbsp;Jialun Huang ,&nbsp;Xiubin Lin ,&nbsp;Hanlin Chen ,&nbsp;Yong Li ,&nbsp;Xianzhang Yang ,&nbsp;Liang Zhang ,&nbsp;Cai Chen ,&nbsp;Jinkai Xia ,&nbsp;Xiaogan Cheng ,&nbsp;Fengqi Zhang ,&nbsp;Ziyi Wang ,&nbsp;Lin Jiang ,&nbsp;Zhuxin Chen ,&nbsp;Beiwei Luo ,&nbsp;Nan Su","doi":"10.1016/j.palaeo.2025.113493","DOIUrl":"10.1016/j.palaeo.2025.113493","url":null,"abstract":"<div><div>The Cenozoic collision between the Indian and Eurasian plates caused widespread intracontinental deformation, which accommodated roughly half of the present-day India-Eurasia convergence rate. However, the mechanisms driving such intracontinental convergence remain debated, particularly regarding the vertically coherent pure-shear thickening model and the decoupled crustal-scale deformation model. The South Tian Shan and the Tarim Basin record substantial Cenozoic intracontinental convergence, and the Kashi foreland basin preserves abundant synorogenic strata, providing a key archive to test these competing models. Herein, we conducted sedimentological and detrital zircon U<img>Pb geochronological analyses of the Neogene–Quaternary strata in the Alparlek section. Stratigraphic observations reveal an overall upward-coarsening facies succession, reflecting a transition from the low-energy depositional environments of the early–middle Miocene Keziluoyi–Pakabulake Formations to the high-energy alluvial systems of the late Miocene–Quaternary Artux–Xiyu Formations. This sedimentary evolution indicates a progressive advance of thrust-induced flexural loading and corresponding basinward migration of the Kashi foreland basin since the mid-Miocene. Detrital zircon U<img>Pb age distributions further document episodic provenance shifts between the South Tian Shan and the northern Tarim Basin, indicating the multistage, basinward growth of foreland fold-and-thrust belts and a migrating orogen–basin boundary. Integrated with previous geophysical studies, these findings indicate that the Neogene intracontinental convergence between the South Tian Shan and the Tarim Basin occurred in a decoupled mode, characterised by southward thrusting of the upper crust of the northern Tarim Basin and the northward underthrusting of its lower crust beneath the South Tian Shan.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113493"},"PeriodicalIF":2.7,"publicationDate":"2025-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799194","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":"Component-specific carbon and oxygen isotope variability in marine limestones of the Mid-Ludfordian (late Silurian) carbon isotope excursion of the Baltic Basin","authors":"Imre Andreas Martin ,&nbsp;Leho Ainsaar ,&nbsp;Aivo Lepland ,&nbsp;Alicja Wudarska ,&nbsp;Maria Rosa Scicchitano ,&nbsp;Tony Prave","doi":"10.1016/j.palaeo.2025.113504","DOIUrl":"10.1016/j.palaeo.2025.113504","url":null,"abstract":"<div><div>The Vidukle-61 core, located in the Baltic Basin of central Lithuania, contains an excellent record of the Mid-Ludfordian Carbon Isotope Excursion (MLCIE; c. 1 Myr duration) identified by carbonate δ¹³C values rising steadily from c. 0 ‰ to 8 ‰, followed by a return to c. 0 ‰ through a 40-m thick interval of marine limestone. Here, we report carbon and oxygen (C<img>O) isotope data obtained by secondary ion mass spectrometry (SIMS) on two samples (VID-1 and VID-3) of bioclastic packstone from the zenith of the MLCIE. As reported in a previous study, the two samples have bulk-rock values of 7.37 ‰ and 8.17 ‰ for δ¹³C and − 5.27 ‰ and − 4.68 ‰ for δ¹⁸O (values relative to VPDB and repeatability ±0.1 ‰). In contrast, high-spatial-resolution SIMS analyses of the same samples show δ¹³C values for the calcitic matrix and spar cement ranging between c. 5 ‰ and 11 ‰, and for fossil fragments between c. 6 ‰ and 13 ‰. δ¹⁸O SIMS values of individual components vary by up to ±2 ‰ relative to the bulk-rock baseline values. Based on SIMS results and observed isotopic variations between individual components, we attribute the bulk-rock values as an admixture of original seawater C<img>O isotope compositions that are best preserved in the bioclasts and the isotopic compositions of later-stage fluids from which spar and matrix-bound microspar precipitated. Our findings emphasize the significant differences between component-specific and bulk-rock C<img>O isotope values. While δ¹³C_bulk curves may capture broad temporal trends in the carbon cycle, high-spatial-resolution and component-specific data reveal microscale isotopic heterogeneity, which can deviate considerably from bulk-rock values. Differentiating and identifying the values that best record original carbonate C<img>O isotopic compositions, even in well-preserved carbonate rocks, requires micro-scale studies to resolve C-isotope heterogeneity in carbonate rocks.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113504"},"PeriodicalIF":2.7,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799343","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":"How volcanoes affect boreal mires: Climate-driven regional vegetation changes and stage-dependent responses to tephra fallout in Kamchatka during the Late Holocene","authors":"Valerii E. Pimenov ,&nbsp;Maria M. Pevzner ,&nbsp;Natalia G. Mazei ,&nbsp;Andrey N. Tsyganov ,&nbsp;Ekaterina G. Ershova ,&nbsp;Yuri A. Mazei","doi":"10.1016/j.palaeo.2025.113501","DOIUrl":"10.1016/j.palaeo.2025.113501","url":null,"abstract":"<div><div>Studying vegetation dynamics in the regions with high volcanic activity is crucial for understanding ecosystem responses to environmental disturbances and predicting future ecological changes. However, the impacts of tephra deposition on vegetation at local and regional scales remain poorly quantified, limiting understanding of ecosystem resilience to volcanic disturbances. This study presents a high-resolution, multiproxy palaeobotanical record from the Kumroch peatland (Kamchatka, Eurasian Far East), integrating detailed tephrostratigraphy, radiocarbon ages, pollen, plant macrofossil, and loss on ignition data. The peat sequence spans the last ∼5 kyr, anchored by 28 recorded tephra layers. Birch forests (<em>Betula ermanii</em>) and alder shrublands (<em>Alnus alnobetula</em> subsp. <em>fruticosa</em>) dominated during the Middle and Late Holocene, with their proportions shifting in response to climate variations. These changes align in timing with the Late Holocene climate oscillations, primarily reflecting temperature fluctuations. Tephra fallout events had no persistent impact on regional vegetation and limited effects on the local vegetation. These findings demonstrate the resilience of boreal ecosystems to tephra deposition across volcanically active areas and underscore the importance of large-scale studies for understanding ashfall-related disturbances.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113501"},"PeriodicalIF":2.7,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799342","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":"Carbonate-associated sulfate isotope signatures in marine mollusk shells","authors":"Shanggui Gong ,&nbsp;Yongbo Peng ,&nbsp;Laurie C. Anderson ,&nbsp;Annette Summers Engel ,&nbsp;Huiming Bao","doi":"10.1016/j.palaeo.2025.113503","DOIUrl":"10.1016/j.palaeo.2025.113503","url":null,"abstract":"<div><div>The oxygen and sulfur isotope compositions of carbonate-associated sulfate (CAS) in biogenic materials, such as mollusk shells, are valuable for inferring paleo-seawater sulfate isotope signatures. However, infaunal species may incorporate sulfate from sediment porewater or, in chemosymbiotic taxa, sulfate metabolized by endosymbiotic sulfur-oxidizing bacteria. To evaluate whether shell CAS primarily records seawater or an ecological niche signature, we measured the δ³⁴S and δ¹⁸O of CAS from 24 modern and Holocene mollusk species spanning epifaunal, shallow infaunal, deep infaunal, and lucinid (chemosymbiotic) habitats across the northeastern Gulf of Mexico, Bahamas and Mexico. Results show substantial isotopic variability (δ³⁴S_CAS: 15.1–22.6 ‰; δ¹⁸O_CAS: 8.5–14.3 ‰): 1) Epifaunal and lucinid δ³⁴S_CAS values cluster near seawater values, while shallow infauna exhibits the greatest variability (up to 7.5 ‰ range), and deep infauna consistently show lower δ³⁴S_CAS (17.1–19.9 ‰) than seawater. 2) All taxa exhibit δ¹⁸O_CAS enrichment above seawater. The absence of ³⁴S-enrichment in infauna suggests limited porewater sulfate incorporation. Epifaunal δ³⁴S_CAS values span a 2.6 ‰ range, with a minimum of 19.5 ‰, implying contributions from non-seawater sulfate, likely dietary sulfur or intracrystalline organic sulfate. Reduced δ³⁴S_CAS in deep infauna also supports these additional sulfate sources incorporation, as deep infauna increased reliance on deposit-feeding of deeper sediment organic matter characterized by decreasing δ³⁴S value. For shallow infauna, their larger variability in δ³⁴S_CAS stems from diverse feeding strategies (filter- and deposit-feeding) and niche adaptations. Bulk CAS of shallow-water lucinid species archive limited ³⁴S-depeted signal of endosymbiont-derived sulfate. CAS oxygen isotope is consistently enriched due to vital effects, with highly variable δ¹⁸O_CAS value across all niches supporting multiple sulfate sources in shells. These findings demonstrate that mollusk shell CAS does not purely record seawater sulfate but incorporates ecological signatures, underscoring the importance of species-specific biology in CAS-based paleoenvironmental or symbiosis studies.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113503"},"PeriodicalIF":2.7,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799355","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":"Multi-system geochronometer constraints on thermo-tectonic evolution of the Qiangtang Terrane, central Tibetan Plateau","authors":"Qingqing Lei ,&nbsp;Xiaofan Wan ,&nbsp;Xiang Ge ,&nbsp;Xiaowei Zeng ,&nbsp;Chuanbo Shen","doi":"10.1016/j.palaeo.2025.113494","DOIUrl":"10.1016/j.palaeo.2025.113494","url":null,"abstract":"<div><div>The Qiangtang Terrane preserves a complete geological record documenting the growth of the central Tibetan Plateau; however, its thermo-tectonic evolution and the timing of topographic development remains debated. This study employs multi-system thermochronology (zircon U–Pb, apatite U–Pb, apatite fission track, apatite (U–Th)/He) of sedimentary strata and magmatic rocks from the Qiangtang Terrane to reconstruct its thermal history. The new thermochronological data show that zircon and apatite U–Pb geochronology from Late Triassic and Eocene igneous rocks yield ages in close agreement at ∼220 Ma and ∼ 35 Ma, respectively. Apatite fission track ages range from 121.2 ± 2.7 Ma to 39.3 ± 2.7 Ma, while AHe ages are between 72.5 ± 1.5 Ma and 27.2 ± 0.6 Ma. Integration of these geochronological data with thermal history modeling constrains four distinct tectonic phases: (1) post-magmatic cooling following the South–North Qiangtang collision during the Late Triassic (∼220 Ma), (2) tectonic deformation and uplift related to the Lhasa–Qiangtang collision during the Late Cretaceous (∼90 Ma), (3) magmatic activity in response to intracontinental subduction during the Eocene (55–36 Ma), and (4) tectonic transition triggered by lithospheric mantle delamination since the post-Oligocene (&lt;35 Ma). Furthermore, by synthesizing previous studies on regional exhumation, magmatic activity, fault systems, and palaeoelevation, this study supports the “Proto-Tibetan Plateau” model and provides new insights into the pulsed growth of the central Tibetan Plateau. Eocene deep-seated magmatic processes generated crustal thickness capable of isostatically sustaining a plateau, which then experienced its final uplift after the Oligocene.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113494"},"PeriodicalIF":2.7,"publicationDate":"2025-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799357","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":"Discerning biotic from abiotic carbonate cementations in Holocene beachrock: mineralogical and geochemical fingerprints for biosignatures","authors":"Xi-yang Zhang ,&nbsp;Ming-zhuang Wang ,&nbsp;Qi Shi ,&nbsp;Fei Tan ,&nbsp;Guo-tao Zhang ,&nbsp;Si-qi Chen ,&nbsp;Hong-qiang Yang","doi":"10.1016/j.palaeo.2025.113454","DOIUrl":"10.1016/j.palaeo.2025.113454","url":null,"abstract":"<div><div>Beachrock cementation, mediated by physicochemical and biological processes, plays a pivotal role in the rapid lithification of coastal sediments. Distinguishing between biotic and abiotic carbonate cements is critical for quantitatively reconstructing diagenetic pathways and accurately evaluating paleoenvironmental conditions. We analyzed Holocene beachrocks from Hainan and the Xisha Islands to compare their cement types. Beachrocks from Hainan are characterized by isopachous high-Mg calcite (HMC) rinds, HMC-rich peloidal fabrics, and blocky–drusy low-Mg calcite (LMC), whereas those from the Xisha Islands are dominated by acicular aragonite. HMC rinds composed of equilong fibrous crystals represent marine phreatic cements with minimal diagenetic alteration, whereas LMC forms through meteoric vadose processes, as indicated by red cathodoluminescent rings. Acicular aragonite nucleates within organic-rich micrite envelopes, with its rapid growth governed primarily by inorganic mechanisms. Peloidal fabrics exhibit distinct fluorescence patterns, dull cathodoluminescence, and elevated Mn/Fe ratios, consistent with their interpretation as microbially mediated precipitates formed during organic matter degradation under intermittently reducing conditions. Notably, peloidal fabrics and aragonite are enriched in bioactive metals (V, Fe, Zn, Pb) relative to coral <em>Porites</em>, consistent with active microbial metabolism. Unlike HMC rinds and acicular aragonite, peloidal fabrics display high total rare earth element (REE) contents, uniform REE distributions, LREE depletion (low LREE/HREE), negative Ce anomalies, positive La anomalies, Y/Ho ratios (∼45), and REE partitioning patterns closely matching modern seawater. These distinctive geochemical signatures establish peloidal fabrics as high-fidelity, high-resolution archives of paleo-seawater chemistry, providing a robust tool for deciphering ancient marine environments.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"684 ","pages":"Article 113454"},"PeriodicalIF":2.7,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145753755","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}