Depositional Record最新文献

{"title":"Mg isotope fractionation during microbial dolomite formation in the Khor Al-Adaid sabkha, Qatar","authors":"Michael Tatzel,&nbsp;Adina Paytan,&nbsp;Samantha Carter,&nbsp;Daniel A. Frick,&nbsp;Marcus Oelze,&nbsp;Francisca Martinez-Ruiz,&nbsp;Zach A. DiLoreto,&nbsp;Elizabeth M. Griffith,&nbsp;Maria Dittrich,&nbsp;Tomaso R. R. Bontognali,&nbsp;Mónica Sánchez-Román","doi":"10.1002/dep2.70072","DOIUrl":"https://doi.org/10.1002/dep2.70072","url":null,"abstract":"<p>The processes governing dolomite [CaMg(CO₃)₂] formation remain among the most debated topics in sedimentary geology. Although primary dolomite can precipitate at low temperatures in certain modern environments, its scarcity today contrasts sharply with its abundance in ancient rocks—a discrepancy known as the ‘dolomite problem’. Dolomite typically forms through two pathways: (1) primary precipitation during early diagenesis, often influenced by microbial activity and organic matter and (2) secondary replacement of preexisting carbonates during burial at higher temperatures. In this study, we investigate Mg isotope fractionation in a modern sabkha in southern Qatar to evaluate its potential as a tracer of dolomite formation processes. We analysed δ²⁶Mg and δ⁴⁴Ca in surface- and pore waters, authigenic clays and organic- and leached dolomite-containing fractions. Ca isotopes reveal an ~1‰ fractionation between pore water–organic matter and dolomite, consistent with a two-step, biologically mediated formation pathway. Contrary, only minor ²⁶Mg enrichment in the organic fraction relative to pore water suggests that Mg isotopes alone provide limited evidence for such microbial mediation. Dolomite δ²⁶Mg values (~−2.15‰) align with predictions for temperature-dependent inorganic precipitation. Overall, the results indicate that microbial activity probably influences dolomite formation indirectly by altering local water chemistry rather than having a distinct Mg isotopic fractionation. These findings refine the application of Mg isotopes as proxies for dolomite genesis and offer new insights into carbonate diagenesis in saline environments.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70072","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147715119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"The Permian–Triassic transition in Türkiye: New insights and 3D outcrop models for accessible, reproducible and sustainable fieldwork","authors":"Baran Karapunar,&nbsp;Xia Wang,&nbsp;Stella Z. Buchwald,&nbsp;Anja B. Frank,&nbsp;Mónica Alejandra Gómez Correa,&nbsp;Müjde Gürsoy,&nbsp;Zhipeng Liu,&nbsp;Xuanni Xu,&nbsp;Lingzan Meng,&nbsp;Damla Demir,&nbsp;Erdal Koşun,&nbsp;Aymon Baud,&nbsp;William J. Foster","doi":"10.1002/dep2.70071","DOIUrl":"https://doi.org/10.1002/dep2.70071","url":null,"abstract":"<p>The Permian–Triassic transition is characterised by major environmental changes and the largest known mass extinction event in the Phanerozoic. However, successions with a relatively complete sedimentological and palaeontological record across the Permian–Triassic are limited to a few well-known sections. The Antalya and Aladağ Nappes in south-western Türkiye provide extensive outcrops of the Permian–Triassic transition. Some key investigations have revealed the importance and potential for these successions to improve our understanding of the events across the Permian–Triassic. Here, we incorporate 3D open-access virtual outcrop models with a virtual field guide to introduce the Permian–Triassic transition in south-western Türkiye, to improve the accessibility, reproducibility and sustainability of fieldwork findings. The fossiliferous Upper Permian to Lower Triassic successions in the studied locations reach over a kilometre thickness. Due to the contemporaneous opening of the Neotethys Ocean, the exposures from the Antalya Nappe (Çürük Dağ in Kemer; Öznurtepe in Gazipaşa; and Demirtaş in Alanya) are considered to be deposited on a southward facing carbonate platform in the Neotethys Ocean, whilst successions from the Aladağ Nappe (Taşkent in Konya) are considered to be deposited on the northern side of the carbonate platform towards the Palaeotethys Ocean. In all sections, the Changhsingian (uppermost Permian) is represented by highly fossiliferous platform carbonates. The Changhsingian successions terminate with a thin oolitic grainstone (‘transitional oolites’), which is identified as the Permian–Triassic mass extinction interval and is characterised by a negative carbon isotope excursion. The transitional oolites are overlain by microbialite-dominated carbonates, and then oolite-dominated carbonates deposited in the Griesbachian. This carbonate-rich deposition was replaced with a mixed carbonate-siliciclastic succession later in the Early Triassic (Dienerian–Spathian), when marine ecosystems slowly recovered. These environmental and biotic changes are similar to the known record from the tropical palaeolatitudes in the western to eastern Palaeotethys.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70071","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147714972","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Reduced sediment accumulation rate enhances early marine diagenesis of periplatform sediments","authors":"Amanda M. Oehlert,&nbsp;Larry C. Peterson,&nbsp;Dick Kroon,&nbsp;Peter K. Swart","doi":"10.1002/dep2.70066","DOIUrl":"https://doi.org/10.1002/dep2.70066","url":null,"abstract":"<p>Early marine diagenesis can alter the δ¹³C values of carbonate sediments in the marine environment, hindering interpretations of changes in global carbon cycling through geological time. In this study, the influence of sediment accumulation rate on the localisation and intensity of diagenetic alteration in the marine burial environment is documented. New measurements of δ¹⁸O and δ¹³C values of bulk carbonate sediments as well as siliciclastic and total organic carbon content were conducted on Holocene–Pleistocene aged sediments collected by Ocean Drilling Program Leg 133 on a proximal–distal transect on the slope adjacent to the Great Barrier Reef. Significantly lower bulk carbonate δ¹³C values and total organic carbon content were found to occur during periods of reduced sediment accumulation, but sediments in these intervals lack obvious sedimentological evidence of alteration, like the development of hardgrounds. New findings suggest that changes in sediment accumulation rate may explain large, asynchronous changes towards lower stable carbon isotope values of marine carbonates deposited in oxygenated slope settings in the geological record. Based on these results, periods of reduced sediment accumulation rate are proposed to enhance diagenetic reactions by providing continued access to oxidants. Alteration during periods of low sediment accumulation rate is likely to be exacerbated in settings containing mixed siliciclastic-carbonate sediments. Finally, while this new observation indicates that subtle early marine burial diagenesis can obscure records of the global carbon cycle preserved in periplatform sediments, new insights may prove useful in constraining the dynamic nature of sedimentation patterns in slope environments through Earth history.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70066","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147565582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Depositional and stratigraphic evolution of a Permian megalake system: Implications for seiche-influenced models","authors":"B. Christofoletti,&nbsp;L. V. Warren,&nbsp;F. G. Varejão,&nbsp;M. G. Rodrigues,&nbsp;M. G. Simões,&nbsp;D. V. Palcu,&nbsp;M. L. Assine","doi":"10.1002/dep2.70067","DOIUrl":"https://doi.org/10.1002/dep2.70067","url":null,"abstract":"<p>The Permian succession of the Paraná Basin records the progressive disconnection from the Panthalassic Ocean that bathed the southwestern Gondwana Supercontinent from the Ordovician to the early Permian. The development of the Gondwanides Belt in the southwestern part of the continent acted as an orographic barrier, restricting marine connections and trapping marine waters in a megalake. In this study, we present a detailed analysis of the transition from marine to continental environments in the Serra Alta and Corumbataí formations, documenting high-resolution stratigraphic sequences with significant hydrological and salinity changes. Our data illustrate how sedimentation and accommodation dynamics shaped the evolution of this continental-scale lake system, which was greatly influenced by meteorological phenomena, including storms and seiches. The megalake experienced transitions between overfilled, brackish to freshwater balanced-fill and saline underfilled stages, associated with distinct fourth-order transgressive and regressive stratigraphic sequences. These changes in water balance and salinity fostered the development of a unique, endemic bivalve-dominated fauna derived from marine ancestors, highlighting the basin's response to changing environmental conditions. Notably, this study identifies tectonic events and climate shifts as primary allogenic forces controlling deposition. Meanwhile, local sediment dynamics and episodic events such as storms and seiches originated key autogenic changes in the resulting stacking patterns. Such meteorological phenomena generated an intriguing heterolithic pattern in the fine-grained lake deposits, which would otherwise be confused with astronomical tides. Our results provide insights into the understanding of sedimentological processes in large lacustrine systems, with implications for paleoclimatic and paleoenvironmental reconstructions in megalakes from the geological record.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70067","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147564855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Correction to ‘Microbial mediation and climatic control on dolomite precipitation in a hypersaline lake: Insights from Salinas Lake, southern Iberia’","authors":"","doi":"10.1002/dep2.70068","DOIUrl":"https://doi.org/10.1002/dep2.70068","url":null,"abstract":"<p>Li, G., Naim, Z., Gibert, L., Stuut, J.-B., Waajen, A.C., Jimenez-Moreno, G., Sánchez-Román, M. Microbial mediation and climatic control on dolomite precipitation in a hypersaline lake: Insights from Salinas Lake, southern Iberia. <i>Depositional Records</i> 2026; 12: e70058.</p><p>The authors regret that errors occurred in Figure 9 and its associated caption and references in the published article.</p><p>In the caption of Figure 9, the citation ‘Lake Caballo Alba (Sánchez-Román et al., 2023)’ was incorrect. The correct citation is ‘Lake Caballo Alba (Sanz-Montero et al., 2023)’.</p><p>The following reference should be included in the reference list:</p><p>Sanz-Montero, M. E., del Buey, P., Cabestrero, Ó., &amp; Sánchez-Román, M. (2023). Isotopic signatures of microbial Mg-carbonates deposited in an ephemeral hyperalkaline lake (central Spain): Paleoenvironmental implications. <i>Minerals</i>, 13(5), 617.</p><p>The authors apologise for these errors and any inconvenience caused.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 2","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70068","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147564054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"An identity card for sabkha dolomite","authors":"Tomaso R. R. Bontognali,&nbsp;Zulfa Al Disi,&nbsp;Maria Dittrich,&nbsp;Zachary DiLoreto,&nbsp;Stefano M. Barnasconi,&nbsp;Fadhil Sadooni,&nbsp;Hamad Al-Saad Al-Kuwari","doi":"10.1002/dep2.70049","DOIUrl":"https://doi.org/10.1002/dep2.70049","url":null,"abstract":"<p>The Dohat Faishakh sabkha in Qatar was among the first modern environments studied to understand low-temperature dolomite formation in association with gypsum and other evaporites. Since the 1960s, research conducted in this sabkha has significantly influenced geological models that remain widely used today, helping in the interpretation of sedimentary sequences that dominated certain periods of Earth's history. Here, we present results of an investigation of the dolomite occurring in this sabkha using techniques more advanced than those available during the initial pioneering studies. By integrating our new results with previously published data, we establish an ‘identity card’ for this sabkha dolomite and the environment it forms. The dolomite exhibits a rhombohedral morphology, contains 50.8 mol% Mg, and has an ordering degree of 0.25 (poorly ordered). Isotopic values are approximately: δ¹³C = 5.0‰, δ¹⁸O = 4.1‰ and δ²⁶Mg = −2.6‰ to −1.5‰ and Δ₄₇ = 0.611‰. Annual temperature data indicate an average of 32.2°C in the subsurface intervals with the highest dolomite content. The associated pore water has an Mg/Ca ratio of 156, a salinity roughly nine times that of sea water and a pH of 6.9. Sediment total organic carbon is ~2%. Microbial diversity in the dolomite-bearing layers is dominated by Euryarchaeota—an extremophilic, opportunistic and metabolically versatile archaeal phylum. Together, these data provide a reference for identifying sabkha-type dolomites in the geological record, calibrating paleoclimatic proxies and interpreting biomarker signals that may be recorded in ancient dolomites.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70049","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146139282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Hydrothermal dolomitisation of a deep-water bioherm isolated in a non-dolomitised intraplatform basin within the Norian Dolomia Principale (Southern Alps, northern Italy)","authors":"Martin Müller,&nbsp;Stefano M. Bernasconi,&nbsp;Vincenzo Picotti,&nbsp;Jordon D. Hemingway","doi":"10.1002/dep2.70060","DOIUrl":"https://doi.org/10.1002/dep2.70060","url":null,"abstract":"<p>The Norian Dolomia Principale in the Southern Alps, northern Italy, is composed of fully dolomitised carbonate platforms, locally interrupted by intraplatform basins that are only partially or not affected by dolomitisation. We studied the intraplatform basinal limestone of the Calcare di Zorzino as well as the dolomitised deep-water Monte Zenone bioherm, which—with an area of ~8 km²—is considered to be one of the largest bioconstructions in the Southern Alps, is isolated within the basinal deposits and is detached from the Dolomia Principale platform. We combine field and petrographic observations with thin section microscopy, X-ray diffraction, cathodoluminescence and both conventional and clumped stable-isotope analyses (δ¹³C, δ¹⁸O, ∆₄₇) of several adjacent carbonate lithologies ranging from non- to fully dolomitised. Reordering models indicate that early diagenetic ∆₄₇ signatures are preserved in bioherm dolomite, whereas Calcare di Zorzino micrite may have experienced both recrystallisation and thermal resetting during the thermal history of the Norian carbonate sequence. Resulting clumped-isotope derived temperatures (<i>T</i>(∆₄₇)) and calculated paleofluid compositions (δ¹⁸O_Fluid) of well-preserved micrite, matrix and cement dolomite document that—in contrast to the Dolomia Principale platform—growth of the Monte Zenone bioherm on a tilted and drowned platform block was controlled by the syn-tectonic and fault-controlled ascent of fluids associated to the Late Triassic–Early Jurassic rifting phase. These deep and warm fluids fostered bioherm growth, with early diagenesis providing the hard substrate for colonisation of microbial communities as well as serpulids and molluscs, and the eventual dolomitisation of the entire bioherm body.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70060","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146140135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Sedimentary records of palaeohydrological variability during the Late Holocene in the Lower Narmada Basin, western India","authors":"Alpa Sridhar,&nbsp;Pooja Tiwari,&nbsp;Biswajit Thakur,&nbsp;Deependra Singh,&nbsp;Vineet Goswami,&nbsp;Sanjit Kumar Jena,&nbsp;Ravi Bhushan,&nbsp;Saremulhaq Parwej Mosarraf Shaikh,&nbsp;Deepak Maurya,&nbsp;Laxman Singh Chamyal","doi":"10.1002/dep2.70053","DOIUrl":"https://doi.org/10.1002/dep2.70053","url":null,"abstract":"<p>It is important to understand the long-term climate variability for better insight into the climate change scenario. The monsoon-fed alluvial rivers of western India provide potential archives for palaeohydrological change. Here we attempt to reconstruct the palaeohydrological variability from the terrace sediments along the Orsang River, a tributary of the Narmada River during the last 1500 years using multiple proxies. The results reveal three distinct depositional phases: I. &gt;1358–1003 cal yr. BP, II. 1003–600 cal yr. BP and III. 600–191 cal yr. BP in the Orsang Basin. The depositional phases I and III correlate with significant global cold and arid climatic phases i.e. DACP and LIA respectively whereas phase II represents the MWP. The high discharge conditions in the Narmada River during the MWP resulted in back flooding and slackwater sedimentation in the Orsang River especially ~704 cal yr. BP as suggested by the Sr-Nd isotopic ratios and high AOM. A significant influx of terrestrial organic matter related to high erosion and runoff due to intense precipitation events prior to 1358, ~1003 and ~601 cal yr. BP in the Orsang River (tributary) marks the climatic transitions. The terrace deposits in the Orsang tributary have recorded the high-magnitude flood events in the Narmada River during wet periods (MWP), and in the tributaries during dry periods, (DACP and LIA). The study demonstrates that tributary terrace sequences are valuable archives for palaeoflood inferences and the use of multiple proxies helps in demarcating local versus regional hydrological events. The inferences underscore the sensitivity of monsoon-dominated fluvial systems to climatic excursions. The regional heterogeneity highlights that climatic shifts during the Late Holocene were not globally uniform. While periods of a stronger Indian Summer Monsoon matched those in Southeast Asia, they contrasted with trends in the Eastern Mediterranean and the Middle East.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70053","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146091194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"A critical role of heterotrophic bacteria in early diagenesis of carbonates through exopolymer degradation and calcium release","authors":"Pieter T. Visscher,&nbsp;Pierre Boussagol,&nbsp;Raphael Bourillot,&nbsp;Christophe Dupraz,&nbsp;Olivier Braissant,&nbsp;Alan W. Decho,&nbsp;Brendan P. Burns,&nbsp;Richard Allen White III,&nbsp;Paxton Tomko,&nbsp;Emmanuelle Vennin","doi":"10.1002/dep2.70057","DOIUrl":"https://doi.org/10.1002/dep2.70057","url":null,"abstract":"<p>The degradation of exopolymeric substances (EPS) by heterotrophic bacteria, concomitant release of calcium ions and precipitation of carbonates were studied in a temperate mountain lake, Lac d'Ilay, Jura France. Phytoplankton blooms in this lake produced large amounts of exopolymeric substances (EPS; 1.8–3.0 mg L⁻¹), probably inhibiting CaCO₃ precipitation by binding Ca²⁺ as shown by the saturation index of calcite and aragonite remaining well below 1. EPS settled to the sediments, where additional polymeric substances were produced by the benthic community. The total amount of EPS decreased downcore from <i>ca</i> 50 μg/g dry sediment near the surface to <i>ca</i> 1.5 μg/g dry sediment at the bottom (120 cm depth). A decrease in acidity, protein and sugar content, and calcium-binding capacity of EPS with depth coincided with active calcite precipitation. Aerobic and anaerobic EPS-degrading heterotrophic enrichments were obtained from the top, middle and bottom of the core. Doubling times of aerobic cultures from the top were six times shorter than those of cultures obtained from the bottom of the core, but anaerobic growth rates were similar across all enrichments. Aerobic turnover rates of organic compounds decreased by a factor of 4–5 from top to bottom; anaerobic rates were similar at all depths, except for the turnover of polymers, which was negligible at the surface compared to rates at the middle and bottom. All enrichments released calcium when grown on EPS. Growth on calcium-saturated EPS in anaerobic cultures obtained from the bottom of the core was the slowest, but still released 26% of the Ca in 20 days. This release during EPS degradation explained an increase in free calcium ions with depth reported in a previous study and may account for a large fraction of the carbonate mud. This suggests that sediments should be considered as an important source of biogenic carbonates.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145996659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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":"Linking palaeo-wildfire to depositional environmental and ecological dynamics of an Early–Middle Pennsylvanian fluvial-tidal transition zone—Palynology and pyrolysis evidence","authors":"Dustin Northrup,&nbsp;Emily Finzel,&nbsp;Pierre Zippi,&nbsp;Kevin Bohacs","doi":"10.1002/dep2.70063","DOIUrl":"https://doi.org/10.1002/dep2.70063","url":null,"abstract":"<p>Pennsylvanian time was characterised by widespread transgressive depositional systems that spanned non-marine to fully marine environments across the North American midcontinent. This study presents new palynological and Rock-Eval pyrolysis data from 113 samples from five cores in the northern Forest City Basin within a depositional-environment framework previously published which integrated a wide range of physical, chemical and biogenic attributes. A total of 153 palynomorph taxa were identified and we interpret depositional environments within a Palaeozoic hydrosere framework. Swamp forest assemblages are dominated by arborescent lycopods (~40%), sub-arborescent lycopods (~15%) and ferns (~25%), with gymnosperms and sphenopsids each composing &lt;10% of the population. Kerogen analyses reveal abundant charcoal, and the ratio of elongated to detrital charcoal decreases upwards from the Kilbourn Formation to the Swede Hollow Formation, reflecting both spatial and temporal changes in wildfire occurrence and charcoal transport processes. Rock-Eval pyrolysis of 30 samples confirms dominantly terrestrial organic matter with Type III and Type IV kerogen. The prevalence of Type IV kerogen and abundant charcoal fragments point to frequent palaeo-wildfires. Stratigraphically, the Kilbourn Formation represents the wettest interval, whereas the overlying Kalo and Floris formations record increased representation of fluvial floodplain and upland assemblages, indicating drier climatic intervals. The Swede Hollow Formation marks a partial return to wetter conditions, coinciding with renewed marine influence recorded by the Oakley Shale. Collectively, these results reveal that the Early–Middle Pennsylvanian landscape of the Forest City Basin was a complex mosaic of swamp forest, floodplain and fluvial upland environments influenced by climatic fluctuations, base-level changes and periodic wildfire activity. The integration of palynological and geochemical data provides the first detailed reconstruction of ecosystem gradients and wildfire patterns across this midcontinent basin, highlighting its role as a key sediment transfer zone and ecological link between continental and marginal marine systems during Pennsylvanian time.</p>","PeriodicalId":54144,"journal":{"name":"Depositional Record","volume":"12 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2026-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dep2.70063","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146002395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}