Sedimentary Geology最新文献

{"title":"Types and formation mechanisms of authigenic quartz in the Late Paleozoic alkaline lacustrine shales, NW China","authors":"Changzhi Li ,&nbsp;Zhiming Li ,&nbsp;Pei Guo ,&nbsp;Jian Wang ,&nbsp;Wangwei Liu ,&nbsp;Baozhen Zhang ,&nbsp;Meiyuan Song ,&nbsp;Kai Zhong ,&nbsp;Jinghong Xu","doi":"10.1016/j.sedgeo.2025.106880","DOIUrl":"10.1016/j.sedgeo.2025.106880","url":null,"abstract":"<div><div>Authigenic quartz controls the storage and mechanical properties of shales, and has attracted a growing attention in marine and continental shales. The silica solubility in alkaline lakes is high due to the high lake water pH (&gt;9) and thus alkaline lacustrine shales generally contain abundant authigenic quartz. However, the occurrences and formation of authigenic quartz in alkaline lacustrine shales and its impact on shales remain poorly studied. To solve these problems, we systematically studied the Late Paleozoic alkaline lacustrine Fengcheng Formation in the Mahu Sag of the Junggar Basin via optical microscope and scanning electron microscope observations and elemental analyses. Four types of authigenic quartz have been identified in the Fengcheng Formation (shales): chert nodules or bands, matrix-dispersed microquartz, mineral-replacive quartz, and veins-filling quartz. The Fengcheng Formation shales contain excess SiO₂ ranging from 11.3 % to 60.4 % based on element calculation and matrix-dispersed microquartz is the dominant type of authigenic quartz, followed by cherts. Cherts and matrix-dispersed microquartz were formed during syndepositional to early diagenetic stage, sourced from pH-driven dissolution of detrital quartz grains and transformation of volcanic materials in highly alkaline water. Both chert and matrix-dispersed microquartz formation can increase the rock strength of shales while matrix-dispersed microquartz can also form massive intercrystalline pores and protect the micropores from compaction. In contrast with marine and non-alkaline lacustrine siliceous shales, alkaline lacustrine shales have a higher abundance and more formation stages of authigenic quartz, and can form high-quality shale reservoirs with high contents of organic matter and authigenic quartz in shallow-water zone.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"482 ","pages":"Article 106880"},"PeriodicalIF":2.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823729","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":"Lacustrine sedimentary evidence of cascading mountain hazards at the inner-Alpine Lake Altaussee (Eastern Alps, Austria) during the Late Holocene","authors":"Marcel Ortler ,&nbsp;Jasper Moernaut ,&nbsp;Markus Fiebig ,&nbsp;Andrea Franco ,&nbsp;Jean Nicolas Haas ,&nbsp;Irka Hajdas ,&nbsp;Philipp Haeuselmann ,&nbsp;Julia Rechenmacher ,&nbsp;Lisa-Maria Weber ,&nbsp;Erwin Heine","doi":"10.1016/j.sedgeo.2025.106881","DOIUrl":"10.1016/j.sedgeo.2025.106881","url":null,"abstract":"<div><div>Inner-Alpine or intramountainous lake systems can be formed by glacial, tectonic or landslide processes and typically present complex sediment dynamics that can drastically change over time and can be driven by various natural hazard processes. Their sedimentary archives can therefore provide insights in the past magnitude and frequency of local mountain hazards, which is key for reliable hazard assessment and understanding of mountain landscape evolution. Here we present morphological, seismic-reflection and sedimentary data from Lake Altaussee, a groundwater-fed lake surrounded by steep topography in the Eastern Alps (Austria). The slow organic-rich sedimentation is interrupted by one phase of inflow (by the Augstbach creek), resulting in clastic sediment input between ~1110–1346 cal yr CE. This inflow phase was terminated by an artificial diversion of the creek as documented in historical reports. The combination of large blocks (max. 70 m in diameter), a mass-flow deposit and megaturbidite deposited on deformed basin floor sediments points to multiple terrestrial mass movements with a total volume of ~430,000 m³ that propagated into the lake and which occurred 755–991 cal yr CE. A 3D hydrodynamic model suggests that the potential mass movement at the northern shore induced an impact wave that inundated the western shoreline with flow depth of up to 9 m and reaching up to ca. 210 m inland. Calculated speed of the backflow indicates that coarse shore sediments can be transported into the lake, which can explain the abundance of gravel/coarse sand at the base of the megaturbidite at the periphery of the basin. Moreover, such impact wave would lead to a standing lake water oscillation (seiching), which is further attested by regular lamination and oscillating grain-size parameters at the base of the main silty unit of the megaturbidite. A persistent change in sediment dynamics around a main subaqueous karst spring pit occurred at 165 cal yr BCE–222 cal yr CE when repeated sediment expulsions from the spring pit started to build up a crater rim. This onset of sediment expulsions is directly overlying a soft-sediment deformation structure (micro-faults). A good age correlation of the two major Altaussee events (i: multiple mass movements, ii: onset of sediment expulsions from spring pit) to large mass-transport deposits in the sedimentary record of the nearby Lake Hallstatt let us hypothesize that two large earthquakes took place in the Late Holocene that led to a multitude of morphological and sedimentary responses in the Upper Traun region. Our findings provide the first indication of an impact wave on a natural lake in the Eastern Alps, highlighting the potential for hazard cascades that remain undocumented in historical records, underscoring the need for reassessing natural hazard risks in alpine lake environments.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"482 ","pages":"Article 106881"},"PeriodicalIF":2.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143851899","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":"Depositional environment and redox conditions of the Moncorvo Ironstone – Unveiling the evolution of ironstones under Rheic Ocean influence","authors":"Emilio Evo Magro Correa Urbano ,&nbsp;Maria Elisa Preto Gomes ,&nbsp;Carlos Augusto Pinto de Meireles ,&nbsp;Paulo Roberto Gomes Brandão ,&nbsp;João Pedro T.M. Hippertt ,&nbsp;Ricardo Scholz ,&nbsp;Cristiano Lana","doi":"10.1016/j.sedgeo.2025.106885","DOIUrl":"10.1016/j.sedgeo.2025.106885","url":null,"abstract":"<div><div>Ironstones, as key archives of past marine environments, provide invaluable insights into Paleozoic history. Their mineralogy may reflect the physical-chemical conditions of the environment and the nature of available sediments. This study focuses on the Moncorvo Ironstone, a Lower-Middle Ordovician deposit formed during the opening of the Rheic Ocean. Here, we use an integrated approach combining sedimentology, petrology, and geochemistry to constrain the depositional settings and the redox landscape associated with the ironstone deposition. The Moncorvo Ironstone present some unusual characteristics, such as the lack of ooids, an uncommon mineralogy, and a stratigraphic thickness that can reach over &gt;45 m, a remarkable feature for an ironstone. Our investigation reveals that this iron-rich sequence is distributed in two distinct marine environments: an inner shelf and a middle to distal shelf. Each environment has a unique mineral assemblage. Despite the influence of metamorphism and deformation, evidence suggests that much of the mineralogy and texture of this deposit still preserve characteristics of the original sediments. Finally, our findings, alongside a careful assessment of the mineralogy of other ironstones of similar age, suggest a strong stratification of the Rheic Ocean throughout the Early and Middle Ordovician.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"482 ","pages":"Article 106885"},"PeriodicalIF":2.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143922727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Climate forcing of turbidite system on the northern South China Sea margin during the Late Quaternary","authors":"Xuan Zhao ,&nbsp;Wei Li ,&nbsp;Christopher J. Stevenson ,&nbsp;Qiang Zhang ,&nbsp;Shuang Li ,&nbsp;Lingyun Wu ,&nbsp;Zhiyuan Cai ,&nbsp;Xiting Liu ,&nbsp;Wenhuan Zhan","doi":"10.1016/j.sedgeo.2025.106884","DOIUrl":"10.1016/j.sedgeo.2025.106884","url":null,"abstract":"<div><div>Turbidites preserved within sedimentary sequences serve as valuable archives of sea-level and climate fluctuations that influence terrigenous sediment supply and depositional processes. However, a comprehensive understanding of how turbidite systems respond to the complex interplay of external forcing on millennial timescales remains limited. Using grain size, geochemical, and chronological data from two sediment cores in different geomorphic settings, we investigate how turbidite system growth responds to sea level, climate and tectonics along the northern South China Sea (SCS) margin. Core QDN-2, located on the northwestern SCS margin, records two turbidites deposited between 43 ka and 12 ka, followed by a cessation of activity during the Holocene. Conversely, core TXN-1 situated on the northeastern SCS margin, documents frequent turbidity currents since 12 ka. These contrasting records demonstrate that turbidite systems on the northern SCS margin can develop at any sea-level. Our findings reveal that while sea level and tectonics play a role, climate emerges as the dominant external forcing on turbidite system development in the northern SCS. Sufficient climate-induced sediment supply compensates for the influence of interception by the wide shelf and high sea level, providing the necessary material basis for the initiation of turbidity currents. The rapid delivery of terrigenous sediments through turbidity currents facilitates the preservation of these climatic signals within the turbidites. This study highlights the crucial role of climate forcing in turbidite depositional patterns, even on the wide continental shelves, and emphasizes the importance of incorporating climate variability into sequence stratigraphic interpretations.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"482 ","pages":"Article 106884"},"PeriodicalIF":2.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916961","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 and oceanographic evolution in the Southern Qiangtang Basin (eastern Tethys) during the latest Pliensbachian to early Toarcian (Early Jurassic)","authors":"Changjun Ji ,&nbsp;Ahmed Mansour ,&nbsp;Yun Chen ,&nbsp;Zhenhan Wu ,&nbsp;Mohamed S. Ahmed ,&nbsp;Wolfgang Ruebsam ,&nbsp;Guoqing Xia","doi":"10.1016/j.sedgeo.2025.106882","DOIUrl":"10.1016/j.sedgeo.2025.106882","url":null,"abstract":"<div><div>The late Pliensbachian-early Toarcian (Early Jurassic) interval is marked by significant climatic changes that affected environmental and paleoceanographic conditions, impacting biogeochemical cycles, as well as marine and terrestrial ecosystems. The most profound environmental changes occurred across the Pliensbachian/Toarcian boundary (P/T B) and in the early Toarcian. Both events align with phases of increased greenhouse gas emissions, global warming, sea-level rises, intensified hydrological cycles, and continental weathering. The Toarcian coincides with the expansion of oxygen-deficient conditions in oceanic and at various shelf areas, marking the Toarcian Oceanic Anoxic Event (T-OAE). In this study, we present high-resolution inorganic geochemical data from the Qixiangcuo section of the Southern Qiangtang Basin, which records both the P/T B and early Toarcian events. The section studied reflects a shallow shelf environment in northeastern part of the Tethys Ocean. Element ratios, such as Ti/Al and Zr/Al, interpreted as sediment grain size proxies, reveal characteristic changes that can be linked to the interplay between sea-level changes and shifts in continental weathering and terrigenous sediment influx. Secular trends in these grain-size proxies reflect sea-level dynamics during the late Pliensbachian-early Toarcian, with notable transgressions at the P/T B and early Toarcian. The early Toarcian event further coincides with increased terrigenous material in response to an intensified hydrological cycle, as evidenced by transient increases in grain-size proxies and higher paleo-weathering indices (e.g., ln(Al₂O₃/Na₂O)). Despite the increased nutrient flux to the paleo-shelf sea, enrichment factors (EF) of productivity proxies (Zn_EF, Cu_EF, Ba_EF, Ni_EF) do not show increases in organic matter export to the sediments. Thus, organic matter-lean sediments (total organic carbon &lt;0.5 wt%) have accumulated in the Southern Qiangtang Basin during the latest Pliensbachian-early Toarcian. The lack of enrichment in redox-sensitive elements, such as Mo, V, and U in the sedimentary rocks of the Qixiangcuo section, points to a well‑oxygenated environment. Accordingly, although the T-CIE is identified in the study section, the T-OAE did not develop in this paleogeographic area. The new data thereby highlight the role of local-regional paleoenvironmental and paleoceanographic parameters as important factors contributing to the genesis of the T-OAE and the burial of organic carbon in marine sediments.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"482 ","pages":"Article 106882"},"PeriodicalIF":2.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143823730","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":"Effects of drying on biofilm-mediated sediment stability in intertidal mudflats: transition from biostabilization to biodestabilization","authors":"Ran Ge ,&nbsp;Yonggang Zhao ,&nbsp;Zheng Gong ,&nbsp;Suna Wang ,&nbsp;Aihong Wei ,&nbsp;Mo Peng ,&nbsp;Honglei Liu","doi":"10.1016/j.sedgeo.2025.106883","DOIUrl":"10.1016/j.sedgeo.2025.106883","url":null,"abstract":"<div><div>The presence and growth of biofilms can considerably enhance sediment stability, a phenomenon known as biostabilization. Intertidal mudflats are periodically exposed to air due to tidal cycles. During exposure, they are affected by drying, which may alter the properties of biofilms and then their sediment-stabilizing ability. However, to date, little information is available on this topic. For this, the effects of a biofilm on sediment stability were investigated over a 15-day drying period. The biofilm was obtained by culturing microorganisms isolated from intertidal sediment. Previous studies demonstrate that biofilms enhances sediment stability in two ways. On one hand, biofilms coating on the surface of sediment bed can protect surface sediment from erosion (surface protection), evidenced by an increase in the critical shear stress of sediment. On the other hand, after the detachment of surface biofilms, biofilms growing between sediment particles can hinder the erosion of bottom sediment (hindered erosion), indicated by less amount of sediment eroded following a same erosion event. Results of this study showed that during the drying process, surface protection was initially enhanced but later weakened, while hindered erosion was consistently weakened. By the end of experimental drying trials, the biofilm no longer stabilized sediment; instead, it reduced the stability of surface sediment and promoted the erosion of bottom sediment, leading to biodestabilization. After drying, the structure of the biofilm covering sediment bed became more compact, similar to that of soil crust, whereas the crust-like biofilm was gradually broken towards the end of experimental drying trials. This alteration explains the observed variations in surface protection. The weakened hindered erosion is associated with the loss of adhesion and aggregation of sediment particles as drying progressed. Moreover, many gas bubbles were generated and trapped within dried biofilm and between sediment particles, which possibly increase the buoyancy of biofilm and weaken the inter-particle bonding of sediment particles, thus leading to biodestabilization.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"482 ","pages":"Article 106883"},"PeriodicalIF":2.7,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845022","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":"Arc-continent collision as recorded in modern stream sand from Oecusse (Timor Island)","authors":"Victor A.S. Vicente ,&nbsp;Pedro Dinis ,&nbsp;Eduardo Garzanti ,&nbsp;Alberto Resentini ,&nbsp;Marta Barbarano ,&nbsp;Marina Cabral Pinto ,&nbsp;João Pratas","doi":"10.1016/j.sedgeo.2025.106852","DOIUrl":"10.1016/j.sedgeo.2025.106852","url":null,"abstract":"<div><div>The small territory of Oecusse in Timor Island has extremely complex geology, influenced by the collision of the Australian continent with the Banda Arc. In Oecusse, sedimentary, volcanic and metamorphic units associated with the lower plate Australian continental margin, the upper plate Banda Terrane, and synorogenic sedimentary successions are exposed. In this study, geochemistry, petrography, and heavy-mineral data on fluvial bedload sand transported by first- and second-order streams are used to better understand the status of arc-continent collision in Timor and the geological nature of the terranes involved in this tectonic process. The presence of upper mantle outliers in Oecusse is readily revealed by serpentinite grains, a heavy mineral assemblage with enstatite, olivine and Cr-spinel, and by Cr, Fe, Sc, Ti, and V concentrations comparable to the Primitive Mantle standard. Volcanic sources occur both in the Banda Terrane and Australian continental margin. The Manamas Formation (Miocene, Banda Terrane) is the most prominent volcanic source, shedding detritus dominated by mafic volcanic rock fragments, plagioclase, and clinopyroxene, with a geochemical signature similar to the Primitive Mantle. The volcanic units of the Barique Formation (Eocene-Miocene, Banda Terrane) and the Maubisse Formation (Permian, Australian continental margin) comprise compositionally heterogenous suites and are intercalated with sedimentary successions, delivering more felsic material, as indicated by the diversified assemblages of lithic fragments and heavy-minerals. Geochemically, they are characterised by lower contents of most compatible elements, higher contents of Th, Y and REE, steeper REE profiles, and stronger negative Eu anomaly than Manamas-derived detritus. These petrographic and geochemical features locally reveal a major felsic volcanic component in the Barique Formation, which cannot be related to the ongoing orogeny because of its proposed late Eocene to early Miocene age. With the exception of coastal sectors where the Manamas Formation is widely exposed, volcanic, sedimentary and low-rank meta-sedimentary rocks partially derived from the Australian lower plate tend to prevail, confirming that arc-continent collision is still at an early stage in the western part of Timor Island.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"481 ","pages":"Article 106852"},"PeriodicalIF":2.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clay mineral of different lithofacies in a continental shallow water delta: Insights from paleoclimate and diagenesis","authors":"Shaoyun Chen ,&nbsp;Yongqiang Yang ,&nbsp;Zaixing Jiang ,&nbsp;Xiaojuan Wang ,&nbsp;Longwei Qiu ,&nbsp;Yerejiepu Habulashenmu","doi":"10.1016/j.sedgeo.2025.106869","DOIUrl":"10.1016/j.sedgeo.2025.106869","url":null,"abstract":"<div><div>Clay minerals in clastic sediments carry important geological information, with their composition and variations reflecting key geological processes. This study investigates the differential clay mineral assemblages among lithofacies within the Middle Jurassic continental shallow-water delta system of the Sichuan Basin, China. Integrated geochemical and XRD analyses demonstrate the significant influence of paleoclimate-driven weathering and diagenetic alteration on clay mineral assemblages. The invariant geochemical characteristics (such as Ti/Al) across different mudstone confirm a uniform provenance, establishing paleoclimate-controlled weathering processes as the principal determinant of clay mineral composition, with negligible provenance influence. Chemical weathering intensity, controlled by the depositional paleoclimate, is a primary factor influencing clay mineral composition in mudstones. In warm, humid climates, abundant rainfall and strong chemical weathering lead to kaolinite enrichment and smectite depletion in black shale facies. Conversely, in cooler, drier climates, physical weathering dominates, resulting in significant illite formation in red mudstone and paleosol facies. In sandstone facies, clay minerals are controlled by diagenetic fluid composition and flux. Chlorite content is related to the primary permeability of the sandstone, while illite content is influenced by K⁺ concentration in diagenetic fluids, with stronger illite enrichment in areas of intense feldspar dissolution. The smectite-to-illite transformation is common in both sandstone and mudstone facies, with its extent influenced by the openness of the diagenetic system and K⁺ availability. In humid conditions, feldspar dissolution in an open system leads to K⁺ advection into sandstone, reducing smectite-to-illite transformation in mudstones. In semi-arid conditions, feldspar dissolution occurs in closed systems during burial, with K⁺ diffusing into mudstones, promoting greater illitization in mudstones than in sandstones. This study provides insights into how paleoclimate and diagenesis control clay mineral transformations in sedimentary rocks.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"481 ","pages":"Article 106869"},"PeriodicalIF":2.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620406","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 comprehensive analysis of the Cambrian Drumian carbon isotope excursion (DICE): Insights from paleoclimate, paleoenvironment and global correlations","authors":"Qiang Gu ,&nbsp;Fengcun Xing ,&nbsp;Karem Azmy ,&nbsp;Xin Jin ,&nbsp;Xiaoquan Chen ,&nbsp;Chunlin Zhang ,&nbsp;Hongshan Qian ,&nbsp;Jiao Wen","doi":"10.1016/j.sedgeo.2025.106875","DOIUrl":"10.1016/j.sedgeo.2025.106875","url":null,"abstract":"<div><div>The Drumian Carbon Isotope Excursion (DICE) has been proposed as a potential marker for the Global Boundary Stratum Section and Point (GSSP) at the base of the Drumian. However, the characteristics of δ¹³C excursions (i.e., strength, number of subpeaks, and range of the excursion) show significant regional variability, necessitating further verification. Additionally, the paleoenvironmental conditions during the DICE event require deeper investigation to better understand their nature and mechanism. The current study examines carbon-isotope variations across the Qinglongshan section, a representative site within the Miaolingian–Furongian carbonate platform of the Ordos Basin, which spans the DICE event. The δ¹³C profile of the section documents several key carbon-isotope excursion events: the global Steptoean Positive Isotopic Carbon Excursion (SPICE, ∼2.5 ‰ positive excursion), DICE (∼4.0 ‰ negative excursion 1), and a potential globally negative excursion 2 (NE2, ∼3.5 ‰) which may correlate with the Drumian–Guzhangian boundary. These excursions are linked to major fluctuations in the carbon cycle and significant environmental changes. Sedimentological and geochemical analyses suggest that the DICE event coincided with marine transgression and a shift from warm and arid to more humid climate. The climate transition likely enhanced chemical weathering and increased terrestrial detrital input, leading to reduced salinity and intermittent anoxic conditions. Variations in seawater chemistry driven by sealevel and terrestrial input fluctuations likely contributed to the deposition of alternating red beds and negative excursion of DICE. Minor discrepancies in the stratigraphic position of the global δ¹³C peak may reflect uncertainties in biostratigraphy or limitations in data resolution. Moreover, terrestrial input is thought to have influenced both the amplitude of the peak negative δ¹³C values and the overall duration of the DICE event.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"481 ","pages":"Article 106875"},"PeriodicalIF":2.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143679207","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":"Sequence stratigraphy in continental endorheic basins: New contributions from the case of the northern extensional Teruel Basin","authors":"Lope Ezquerro ,&nbsp;Carlos L. Liesa ,&nbsp;José L. Simón ,&nbsp;Aránzazu Luzón","doi":"10.1016/j.sedgeo.2025.106868","DOIUrl":"10.1016/j.sedgeo.2025.106868","url":null,"abstract":"<div><div>The tectono-sedimentary analysis is a sequence stratigraphy method particularly useful in continental tectonically active basins far from the influence of sea level changes. It provides a comprehensive study of the sedimentary features and stratigraphic architecture of a basin focusing on the stratigraphical, mainly cyclic, trend of the rock record in order to define genetic (tectono-sedimentary units-TSUs) controlled by allocyclic factors: tectonics and climate. The tectono-sedimentary analysis has been traditionally used in basins related to compressive stress regimes, but their application in extensional basins is less common. In this work the results of the detailed tectono-sedimentary analysis of the northern Teruel Basin rocks are presented. Vertical and lateral distribution of mappable lithofacies associations reveal different depositional systems laterally related and the main paleogeographic changes from the Late Miocene to Early Gelasian (11–1.8 Myr). Five main alluvial progradational-retrogradational cycles integrate six TSUs with chronostratigraphical meaning, bounded by isochronous stratigraphic surfaces (sedimentary breaks) that represent maximum alluvial progradations, and define the basin geodynamic framework. A main challenge, not commonly addressed in this kind of studies, is the discrimination of the effects of tectonic and climate for each unit, which has been based on evidences of synsedimentary tectonism in combination with δ¹⁸O_PDB isotope data. It is demonstrated that the sedimentary evolution was mainly controlled by the tectonics, with the phases of tectonic activity being consistently recorded as alluvial progradations (correlative lacustrine retractions) and climate only modulating (amplifying or vanishing) the tectonic effects. Certain guidelines are proposed to adequately recognize and characterize genetic units in continental extensional basins. Our results reinforce TSUs as very valuable tools for studying active continental basins far from sea level effects and to discriminate the influence of allogenic controls in sedimentation.</div></div>","PeriodicalId":21575,"journal":{"name":"Sedimentary Geology","volume":"481 ","pages":"Article 106868"},"PeriodicalIF":2.7,"publicationDate":"2025-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143679208","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}