Palaeogeography, Palaeoclimatology, Palaeoecology最新文献

{"title":"Reconstructing paleo-drainage in southern Tibet prior to the India-Asia collision: Provenance constraints from the Shexing Formation","authors":"Jiawei Zhang ,&nbsp;Jingen Dai ,&nbsp;Xinyu Qian ,&nbsp;Yukui Ge ,&nbsp;Shuai Li ,&nbsp;Jiarun Tu ,&nbsp;Huiping Zhang ,&nbsp;Ying Wang ,&nbsp;Kang Liu ,&nbsp;Xudong Zhao","doi":"10.1016/j.palaeo.2025.113314","DOIUrl":"10.1016/j.palaeo.2025.113314","url":null,"abstract":"<div><div>The configuration of drainage networks along the southern Asian margin prior to the India-Asia collision is critical for understanding long-term landscape evolution, yet remains poorly constrained. Here, we integrate sedimentological, petrographic, and detrital zircon U<img>Pb geochronological data from the Shexing Formation, deposited in the backarc basin of the Gangdese arc, to reconstruct the pre-collisional drainage system of southern Tibet. Sedimentological evidence indicates predominantly fluvial deposition with localized shallow marine influence. Maximum depositional ages derived from detrital zircon U<img>Pb data constrain basin fill to ∼119–84 Ma. Quantitative provenance analysis reveals that the majority of sediment was sourced from the north-central Lhasa terrane (contributing 41–99 %), with only minor contributions from the Gangdese arc. This provenance pattern, when integrated with the published tectonic subsidence history, supports a backarc basin model that was likely triggered by the rollback of the Neo-Tethyan oceanic lithosphere. Combining paleocurrent measurements, spatial correlation with coeval strata in the Xigaze forearc and trench basins, and detrital zircon age signatures, we propose that during the deposition of the Shexing Formation, multiple transverse rivers, rather than a single axial system, cut through the Gangdese arc along the southern Asian margin. The inferred paleogeographic configuration may have resembled that of modern Taiwan, where sub-parallel rivers sourced in the Central Mountain Range traverse sedimentary plains and incise through the Coastal Range before discharging into the ocean. Continued uplift of the Gangdese arc subsequently reorganized regional drainage, shifting from a southward flow to an axial configuration sometime between the Late Cretaceous and the Miocene.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"679 ","pages":"Article 113314"},"PeriodicalIF":2.7,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A deep-water Rencunping sequence response to astronomical forcing during the late Permian in South China","authors":"Xingfang Peng ,&nbsp;Kexin Zhang ,&nbsp;Yan Chen ,&nbsp;Chen Wu ,&nbsp;Ze Zhang ,&nbsp;Yang Zhang ,&nbsp;Weihong He","doi":"10.1016/j.palaeo.2025.113318","DOIUrl":"10.1016/j.palaeo.2025.113318","url":null,"abstract":"<div><div>The timing of the end-Permian mass extinction can be established from astronomically controlled climate cycles recorded in continuous marine sedimentary sections. The high-resolution cyclostratigraphic analysis is carried out on the deep-water Permian-Triassic boundary (PTB) sequence at the Rencunping section, Sangzhi County, South China. Physical and chemical proxy records reveal the presence of the complete suite of orbital frequencies in the Milankovitch bands, providing strong evidence for 405-kyr and 100-kyr eccentricity forcing throughout the Permian-Triassic boundary intervals. Floating astronomical time scales (ATS) are established for the discussion and comparison on the late Permian mass extinction and crisis between deep-water and shallow-water sections. Here we estimate durations of 2268 kyr for Changhsingian stage, 609 kyr for the Changhsingian conodont <em>Clarkina yini</em> Zone, and 1316 kyr for the ammonoid <em>Pseudotirolites-Rotodiscoceras</em> Zone, based on 405-kyr astronomical eccentricity tuning. Previous studies revealed that the biotic and environmental depletion began in deep waters earlier than the crisis in shallow waters. This study suggests that the extinction and environmental deterioration in deep waters started at least about 270 kyr before the PTB and 66–101 kyr earlier than the counterpart in shallow water. The deterioration is primarily explained as associated with frequent volcanism and its induced cascade of negative environmental and ecological effects. The volcanism was triggered by the subduction of Paleotethyan Ocean in South China.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"679 ","pages":"Article 113318"},"PeriodicalIF":2.7,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221143","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":"Platinum-group elements record both weathering changes and volcanic input through the Pliensbachian–Toarcian transition at Peniche, Portugal","authors":"Heiðrikur í Garði Mortensen ,&nbsp;Stéphane Bodin ,&nbsp;Alicia Fantasia ,&nbsp;Rasmus Andreasen ,&nbsp;Sofie Lindström ,&nbsp;Ambre Luguet ,&nbsp;Christian Tegner","doi":"10.1016/j.palaeo.2025.113311","DOIUrl":"10.1016/j.palaeo.2025.113311","url":null,"abstract":"<div><div>Large igneous provinces (LIPs) are thought to be the drivers of numerous Mesozoic episodes of dramatic environmental perturbation due to massive influx of volcanically sourced CO₂ and subsequent enhanced global weathering rates. Two such episodes studied here are the Pliensbachian-Toarcian (Pl/To) event, closely followed by the Toarcian oceanic anoxic event (T-OAE), both of which have been temporally linked to eruption phases of the Karoo and Ferrar LIPs (KFLIP). Here we present high-precision platinum-group element (PGE) data for the sedimentary succession spanning across the Pl/To and the T-OAE from the Toarcian Global Stratotype Section and Point (GSSP) at Peniche, Portugal. The concentrations of PGEs peak across both Pl/To and the T-OAE, and correlate with Hg enrichment and negative carbon-isotope excursions reported from these intervals. They are also positively correlated with siliciclastic content (e.g., Al, Zr and Ti) and weathering proxy variations from these intervals (i.e., ¹⁸⁷Os/¹⁸⁸Os and ⁸⁷Sr/⁸⁶Sr), although there are still enrichments in PGE/Al at both intervals. Pd/Ir and Pt/Ir ratios are slightly higher than in continental crust (∼30–80 for Peniche samples and ∼ 22 for UCC), but similar to basalts from KFLIP. These observations, together with Hg concentrations, ¹⁸⁷Os/¹⁸⁸Os and ⁸⁷Sr/⁸⁶Sr ratios, are best explained by elevated continental weathering and additional volcanic input. These results support the hypothesis that KFLIP eruptions were responsible for both Pl/To and T-OAE, and further show that PGEs are a powerful proxy for fingerprinting volcanism and weathering.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"679 ","pages":"Article 113311"},"PeriodicalIF":2.7,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221270","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":"Guttulatic calcite evidence for carboniferous icehouse climate in the Ordos Basin, North China Craton","authors":"Jiaqi Yang ,&nbsp;Zhiliang He ,&nbsp;Juntao Zhang ,&nbsp;Keyu Liu ,&nbsp;Macro Brandano ,&nbsp;Jingbin Wang","doi":"10.1016/j.palaeo.2025.113306","DOIUrl":"10.1016/j.palaeo.2025.113306","url":null,"abstract":"<div><div>Although the Carboniferous Icehouse Climate resulted in extensive glaciation, its impact on the palaeoclimate in the North China Craton remains enigmatic owing to the stratigraphic hiatus that occurred from the Middle Ordovician to the Late Carboniferous. Guttulatic calcite in the rock record is often used as a proxy for frigid climate conditions. By integrating cathodoluminescence (CL), petrological analysis, and <em>in situ</em> geochemical analysis, the guttulatic calcite was identified, enabling teconstruction of the palaeoclimate evolution during the Carboniferous in the Ordos Basin. The guttulatic calcite in the study area is composed of core and annular overgrowth exhibiting multi-bands polarized colours and synergistic CL response changes. The characteristics of major, trace, rare earth elements, and Sr isotope are consistent for the same polarized colour cement but vary among cements with bright and dark colours. Bright and dark calcite cements represent different weathering intensities; bright calcite cement is a faithful recorder of palaeoclimate variations, with guttulatic calcite representing past icehouse events. Part of the Carboniferous palaeoclimate changed from arid to humid and then to semi-arid, corresponding to weathering intensity variations from weak to strong, and then to moderate, indicating the periodic disappearance of an icehouse climate in the Ordos Basin.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"679 ","pages":"Article 113306"},"PeriodicalIF":2.7,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158837","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":"Carbon isotope chemostratigraphy, detrital zircon geochronology, and microfossils from the Rio Pardo Group, NE Brazil: Implications for the Cryogenian interglacial dynamics","authors":"Henrique Albuquerque Fernandes ,&nbsp;Leonardo Thomaz Rimi ,&nbsp;Iure Rocha Teixeira ,&nbsp;Claudia Regina Passarelli ,&nbsp;Ligia Stama ,&nbsp;Vinicius Cardoso Lucas ,&nbsp;Valderez Pinto Ferreira ,&nbsp;Alcides Nóbrega Sial ,&nbsp;Wilker dos Santos Cezario ,&nbsp;Juliana de Moraes Leme ,&nbsp;Ivo Karmann ,&nbsp;Paulo César Boggiani","doi":"10.1016/j.palaeo.2025.113305","DOIUrl":"10.1016/j.palaeo.2025.113305","url":null,"abstract":"<div><div>The Sturtian (ca. 720–661 Ma) and Marinoan (ca. 650–635 Ma) Snowball Earth glaciations caused major disturbances to Earth's biosphere and biogeochemical cycles during the Cryogenian. The nonglacial interval in-between these glaciations records the putative emergence of macrofossils, increased biotic complexity, and significant perturbations to the global carbon cycle, making it an optimal archive for investigating Cryogenian ecosystems and enabling global correlation of sedimentary successions through chemostratigraphy and paleontological data. Despite this clear significance, some Cryogenian basins remain poorly investigated. Here we present field data, detrital zircon geochronology, carbon isotope chemostratigraphy, and new microfossils from the Rio Pardo Group, northeastern Brazil. This group includes, from base to top, the Panelinha Formation, the Itaimbé Subgroup (with the lateral equivalents Camacã, Água Preta, Serra do Paraíso, and Santa Maria Eterna formations), and the Salobro Formation. The basal diamictite of the Panelinha Formation rests unconformably on the crystalline basement and is here associated with the Sturtian Glaciation. The Serra do Paraíso Formation, stratigraphically above, comprises dolostones interbedded with pelites deposited in a mixed carbonate-siliciclastic marine platform during the nonglacial interval. These dolostones display positively fractionated δ¹³C_carb values (up to +8 ‰), typical of the glacial interlude δ¹³C_carb plateau. The overlying Salobro Formation contains diamictites, correlated with the Marinoan Glaciation. Detrital zircon data from the Panelinha and Salobro formations indicates that ca. 2.1 Gyrs-old basement rocks were the primary sediment sources for these units. Carbonaceous compressions microfossils (CCMs) and agglutinated microfossils (AMs) were found in microbialites and rhytmites of the Serra do Paraíso Formation. Raman spectroscopy and EDS analyses reveal an association of organic matter and silica in the CCMs, as well as phosphate. AMs, in turn, present agglutination of clay minerals. This study highlights the Rio Pardo Group as a key unit in Brazil and expands the record of Cryogenian microfossil-bearing successions worldwide. If the CCMs presented here are indeed associated with vase-shaped microfossils (VSMs), this would represent the second report of VSMs in Cryogenian strata to date.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"679 ","pages":"Article 113305"},"PeriodicalIF":2.7,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158835","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":"Late Permian to Early Triassic tectonic uplift of the Qinling Orogenic Belt in response to initial collision of the North and South China blocks: a sediment provenance analysis","authors":"Yinan Zhao,&nbsp;Wentao Yang,&nbsp;Jinkun Zhu,&nbsp;Qiang Fu","doi":"10.1016/j.palaeo.2025.113303","DOIUrl":"10.1016/j.palaeo.2025.113303","url":null,"abstract":"<div><div>The tectonic uplift of the Qinling Orogenic Belt (QOB) records the collision of the North and South China blocks. This study employs sandstone petrography, detrital zircon U<img>Pb geochronology, paleogeographic reconstructions, and paleocurrent data, to investigate the provenance of sediments from Late Permian to Early Triassic strata in the Fengxian area of the QOB, and to understand tectonic evolution of the belt. Detrital zircons from the Late Permian Shilidun Formation and the earliest Triassic Xipo Formation show two primary age populations (Late Paleozoic and Neoarchean to Paleoproterozoic), with sediments likely sourced from recycled sedimentary strata in the southern margin of the North China Block (S-NCB). Detrital zircons from the upper Xipo Formation and the Early Triassic Renjiawan Formation are concentrated in two age populations (Early Paleozoic and Neoproterozoic), being primarily derived from the North Qinling Belt (NQB). These provenance data suggest that the S-NCB underwent uplift during the Late Permian and earliest Triassic while significant uplift commenced in the NQB during the late Early Triassic. These uplift patterns are consistent with an overstep thrust tectonic evolution model for the collisional margin. Combined with sedimentary records from both the northern and southern sides of the QOB, this study proposes that the initial collision between the North and South China blocks in the central QOB occurred during the Late Permian.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"679 ","pages":"Article 113303"},"PeriodicalIF":2.7,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221142","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":"An uplift of the southeastern Tibetan Plateau around 12.1 Ma encoded in coal seam","authors":"Min Huang ,&nbsp;Guanyu Zhao ,&nbsp;Qiang Wang ,&nbsp;Bin Cheng ,&nbsp;Zewen Liao","doi":"10.1016/j.palaeo.2025.113300","DOIUrl":"10.1016/j.palaeo.2025.113300","url":null,"abstract":"<div><div>The orogeny of the Tibetan Plateau represents a significant geologic event with profound implications for the evolution of Earth's ecological systems. Despite its importance, the intricacies of the plateau's episodic uplift during the Neogene period remain insufficiently understood. This study examines a Neogene coal seam in the Xiaolongtan region of Yunnan Province in China, located at the plateau's southeastern extremity. Our research focuses on the bulk stable carbon/hydrogen isotope change of coal, particularly the content and isotope variation of methoxyl groups bonded to the coal molecules along the coal seam, to probe the possible correlational dynamics between these proxies and the uplift of Tibetan Plateau. The results showed that the methoxyl content and its stable carbon/hydrogen isotopic composition, and the bulk coal stable carbon/hydrogen isotopes fluctuate distinctly along the coal seam, particularly the synchronous excursions of the bulk coal stable hydrogen isotopes, as well as methoxyl content and its carbon isotopes occur around 12.1 Ma within the coal seam. In light of the existing research outcomes, these results suggest that the southeastern part of the plateau underwent a notable elevation for an approximate ascent of 500 m from 12.10 to 12.02 Ma in the Xiaolongtan area.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"679 ","pages":"Article 113300"},"PeriodicalIF":2.7,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145221271","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":"Pulsed volcanism in the Emeishan Large Igneous Province drove deglaciation during the Guadalupian-Lopingian transition","authors":"Cheng Cheng ,&nbsp;Hua Zhang ,&nbsp;Dan Wang ,&nbsp;Shuangying Li ,&nbsp;Shuzhong Shen","doi":"10.1016/j.palaeo.2025.113302","DOIUrl":"10.1016/j.palaeo.2025.113302","url":null,"abstract":"<div><div>The Guadalupian-Lopingian transition (late Permian, ∼260 Ma) was a critical turning point in Earth's climate evolution, marking the end of the Late Paleozoic Ice Age (LPIA) and concurrent perturbations in the global carbon cycle. Although the Emeishan Large Igneous Province (ELIP) has been proposed as a potential trigger of this episode, the mechanistic linkages between volcanic pulses, climate fluctuations, and deglaciation remain poorly constrained. Here, we present an integrated high-resolution analysis of the carbonate-dominated Xikou section (South Qinling, China), which spans the Guadalupian-Lopingian interval, and report new data for mercury geochemistry (Hg/TOC anomalies as volcanic proxies), paired carbonate and organic carbon isotopes (δ¹³C_carb, δ¹³C_org), redox-sensitive trace elements (e.g., Mo_EF), and chemical weathering indices (e.g., chemical index of alteration, CIA). Results reveal five distinct volcanic pulses (e.g., Hg/TOC peaks of up to 150 ppb/wt%) during the Capitanian to Wuchiapingian, each roughly coinciding with negative δ¹³C excursions (up to −2.5 ‰), elevated CIA values (up to 88), and synchronous enrichments in redox-sensitive elements (e.g., Mo_EF up to 100). This triple coupling demonstrates that ELIP eruptions released massive amounts of ¹³C-depleted CO₂, driving recurrent episodes of warming that progressively destabilised the P4 glaciation and led to ice-sheet collapse. This mechanism can be extended to the global deglaciation of the LPIA because eruptions from the Tarim II (ca. 290 Ma), Tarim III (ca. 280 Ma), and Emeishan LIPS (ca. 260 Ma) are each associated with interglacial phases. Furthermore, a prominent +1.4 ‰ shift in Δ¹³C (δ¹³C_carb - δ¹³C_org) during the early Wuchiapingian suggests enhanced organic carbon burial under waning volcanism, promoting atmospheric oxygenation and ecosystem recovery. Our study establishes pulsed volcanism as the primary driver of icehouse-greenhouse transitions through carbon cycle disruption, with implications for understanding climate-biosphere feedbacks during the late Permian crises.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"679 ","pages":"Article 113302"},"PeriodicalIF":2.7,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158831","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":"Effect of Late Cretaceous marine incursions on lacustrine organic carbon burial in East Asia: Perspectives from machine learning and geochemistry","authors":"Baiqiang Tang ,&nbsp;Qingtao Meng ,&nbsp;Fei Hu ,&nbsp;Nan Jiang ,&nbsp;Liang Yang ,&nbsp;Jilin Xing ,&nbsp;Zhaojun Liu ,&nbsp;Yunbai Zhang","doi":"10.1016/j.palaeo.2025.113304","DOIUrl":"10.1016/j.palaeo.2025.113304","url":null,"abstract":"<div><div>The relationship between lacustrine organic carbon burial and marine incursion has been investigated extensively, yet the mechanisms by which marine incursions control organic carbon burial remain unclear. The Songliao Basin, one of the largest continental basins in East Asia during the Cretaceous, provides an ideal natural laboratory to address this issue. This study focuses on the first member of the Qingshankou Formation (K₂qn¹) of the Late Cretaceous in the Songliao Basin, northeast China. Trace-element ratios, molecular biomarkers, and strontium isotopes demonstrate episodic marine incursions and indicate that the Southeastern Uplift was more strongly influenced by marine incursion than the Central Depression. As marine incursions intensified, the contribution of algae increased, primary productivity rose, anoxic conditions intensified, and salinity in the water column increased. Collectively, these processes markedly enhanced organic carbon burial. Spatial distributions of Sr/Ba, pristane/phytane (Pr/Ph), and total organic carbon (TOC) corroborate these lacustrine responses to marine incursions. A model was developed using XGBoost to quantify organic carbon burial using sedimentary environment indicators as input, specifically paleoclimate (Sr/Cu), paleosalinity (Sr/Ba), paleoredox (C_org/P), and paleoproductivity (Cu/Al); TOC served as the target variable. Results demonstrated that the XGBoost model captured the nonlinear relationship between depositional environments and organic carbon burial associated with marine incursion. Shapley Additive exPlanations (SHAP) identified paleoproductivity as the principal control on burial, followed by redox conditions. This study demonstrates the utility of machine learning in elemental geochemistry and provides a quantitative characterization of how marine–terrestrial interactions influence organic carbon burial in lacustrine depositional environments.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"679 ","pages":"Article 113304"},"PeriodicalIF":2.7,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145158832","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":"Oxygen levels regulate the co-evolution of non-terrigenous silica and organic matter in deep- to semi-deep waters during the Ediacaran–Cambrian transition","authors":"Hezheng Dong ,&nbsp;Dongsheng Zhou ,&nbsp;Yufei Liang ,&nbsp;Lei Huang","doi":"10.1016/j.palaeo.2025.113301","DOIUrl":"10.1016/j.palaeo.2025.113301","url":null,"abstract":"<div><div>During the Ediacaran–Cambrian (E–C) transition, marine black shales enriched in carbon (C) and silicon (Si) were widely deposited. However, the migration mechanism of Si in bathyal to abyssal zones remains unclear, and the key factors controlling the co-evolution of non-terrigenous silicon (NTS) and organic matter (OM) are still undefined. In this study, we focused on deep- to semi-deep water black shales in the upper Dengying Formation (Upper Sinian) and the lower Wangyinpu Formation (Lower Cambrian) of the Pukoucun section in northwestern Jiangxi Province, South China. Using an integrated approach that combines mineralogy, organic geochemistry, and element geochemistry, we investigated the factors controlling the co-evolution of the OM burial and NTS deposition in deep- to semi-deep water environments. The results suggest that the co-evolution of the OM and NTS in deep- to semi-deep water zones differs significantly from that in shallow-water environments. Hydrothermal fluids from the Jiangnan deep fault provided abundant hydrothermal Si, which diffused from hydrothermal vents into broader areas in the form of Fe(II)-silicate gels. In addition, the redox proxies (Mo_EF, U_EF, C_org/P, Ni/Co) show an increasing trend from the late Ediacaran to the early Cambrian, indicating that oxygen levels during this period exhibited an overall decreasing trend, accompanied by periodic fluctuations. Based on the co-variation relationships among Si_ex, TOC, Eu/Eu^⁎, and Fe/Al, it can be concluded that aqueous oxygen levels was the key controlling factor for the co-evolution of OM and NTS in deep- to semi-deep water settings along the southeastern margin of the Yangtze Platform during the E–C transition. We propose a new model of the co-evolution process, in which the extent of the marine dynamic anoxia zone influences the migration distance of Fe(II)-silicate gels, thereby regulating the sedimentation flux of NTS in distal vent areas. Based on these observations, NTS is predominantly removed from seawater in an inorganic form, and its enrichment may dilute the concentration of OM. These findings enhance our understanding of how marine redox evolution influenced the C<img>Si cycle during the E–C transition and provide novel insights into shale OM enrichment mechanisms.</div></div>","PeriodicalId":19928,"journal":{"name":"Palaeogeography, Palaeoclimatology, Palaeoecology","volume":"679 ","pages":"Article 113301"},"PeriodicalIF":2.7,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145118937","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}