Journal of Palaeogeography最新文献

{"title":"Geochemical characteristics of the Upper Triassic Tanzhuang Formation in the Jiyuan sag, southern North China Block: Implications for the depositional environment and organic matter enrichment","authors":"Wei-Qing Liu ,&nbsp;Lu-Qi Chen ,&nbsp;Hua-Ying Song ,&nbsp;Yu Qiao ,&nbsp;Su-Ping Li ,&nbsp;Wei Wu ,&nbsp;Chang-Song Lin ,&nbsp;Jian-Xin Yao","doi":"10.1016/j.jop.2025.100290","DOIUrl":"10.1016/j.jop.2025.100290","url":null,"abstract":"<div><div>The organic-rich black oil shales of the Upper Triassic Tanzhuang Formation represent important source rocks within the southern North China Block. However, the mechanism of organic matter enrichment remains unclear. Additionally, the climate evolution and driving factors of the Late Triassic in the southern North China Block are still unknown. This study explores the paleoclimate, paleohydrology, paleoenvironment, and organic matter accumulation mechanism of the section containing the Tanzhuang Formation in the Jiyuan area, utilizing its geochemical characteristics as a basis for analysis. The oil shales in the Tanzhuang Formation can be categorized into two types: organic-rich shales (with total organic carbon (TOC) contents varying between 1.61 % and 4.17 %) and organic-lean shales (with TOC contents varying between 0.29 % and 1.44 %). The paleoclimatic indices, the chemical alteration index (CIA) and the C value, suggest that the organic-lean shales were deposited under warm and semihumid paleoclimatic conditions, whereas the organic-rich black shales formed under warm and humid climate conditions. The positive correlation between the Hg/Al ratios and C values suggests that volcanic activity was the cause of paleoclimatic changes, which may have been associated with global climatic events that occurred during the Late Triassic Carnian period. The oxidation–reduction indices, V, U, and Mo contents and the Mo–U correlation diagram indicate that dysoxic conditions prevailed in the Jiyuan Basin during the deposition of the oil shales in the Tanzhuang Formation. The primary productivity indices (e.g., Cu_EF and Zn_EF) suggest that higher primary productivity was observed during the deposition of the organic-rich shales. The positive correlations between the TOC contents and the Cu_EF and C values indicate that the enrichment of organic matter in the oil shales of the Tanzhuang Formation was influenced primarily by primary productivity and a warm and humid climate. The sedimentary model indicates that the elevated primary productivity may have originated from a warm and humid climate coupled with intense weathering caused by volcanic activity during the Late Triassic period, which formed a productivity model characterized by the accumulation of organic matter in the oil shales of the Tanzhuang Formation.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100290"},"PeriodicalIF":2.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145157624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The optical textures of pyrobitumen in nature and its geological significance: revealed from the Ediacaran pyrobitumen in the central Sichuan Basin, SW China","authors":"Lian-Qiang Zhu ,&nbsp;Ze-Zhang Song ,&nbsp;Bing Luo ,&nbsp;Guang-Di Liu ,&nbsp;Wen-Zhi Zhao ,&nbsp;Qian-Qian Feng ,&nbsp;Ben-Jian Zhang ,&nbsp;Gang Zhou ,&nbsp;Xing-Wang Tian ,&nbsp;Dai-Lin Yang ,&nbsp;Lu-Ya Wu ,&nbsp;Lin Ma ,&nbsp;Mikhail Spasennykh ,&nbsp;Yi-Shu Li","doi":"10.1016/j.jop.2025.100271","DOIUrl":"10.1016/j.jop.2025.100271","url":null,"abstract":"<div><div>Some natural pyrobitumens exhibit optical anisotropy similar to mesophase asphalt, potentially recording critical geological information. However, the significance of their distinctive optical textures remains understudied. Anisotropic pyrobitumen in the Ediacaran Dengying Formation (central Sichuan Basin, southwestern China) provides a key example. This study investigates controls on pyrobitumen optical texture evolution using petrography, scanning electron microscopy, and U–Pb dating. Then, it discusses the relationship between these textures and anomalous thermal events by analyzing their spatial distribution and their geological significance. Results reveal that anisotropic pyrobitumen in Dengying Formation formed from oil cracking caused by Late Permian hydrothermal activity. These pyrobitumen can be divided into two categories based on the optical textures: fibrous and mosaic, reflecting distinct internal physical structures. Fibrous pyrobitumen exhibits more ordered aromatic layers than the mosaic type. Temperature primarily controls optical textures by regulating polycondensation reactions and pyrobitumen viscosity. Although the Gaoshiti and Moxi areas share similar burial histories, Gaoshiti is dominated by highly evolved fibrous pyrobitumen, while Moxi contains predominantly low-evolved mosaic pyrobitumen. This disparity indicates formation of anisotropic pyrobitumen was unrelated to normal burial temperatures but to hydrothermal activity. This study demonstrates that anisotropic pyrobitumen cannot form below 240 °C, even over extended durations. Consequently, in situ anisotropic pyrobitumen in deep strata serves as an indicator of paleo-thermal anomalies, with varying textures acting as proxies for relative temperatures within these events. Under identical geological settings, fibrous pyrobitumen typically records higher temperatures than mosaic pyrobitumen.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100271"},"PeriodicalIF":0.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144695053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights into the biostratigraphy of the Silurian–Devonian transition in Southwestern Gondwana, based on a new graptolite record from Argentina","authors":"Fernando E. Lopez ,&nbsp;Juan J. Rustán ,&nbsp;Juan L. Benedetto","doi":"10.1016/j.jop.2025.100265","DOIUrl":"10.1016/j.jop.2025.100265","url":null,"abstract":"<div><div>The Silurian–Devonian transition witnessed not a single mass faunal turnover but minor extinctions and recovery intervals. Planktonic graptolites experienced a reduction in diversity before their extinction in the Early Devonian. Due to the scarce fossil record from high-latitude cold waters, these interpretations have been primarily based upon the best known low-latitude faunas. The graptolite herein presented is the first record of latest Silurian to possibly Devonian age from high southern paleolatitudes of Gondwana. A new fossil locality of the Argentine Precordillera yielded <em>Slovinograptus</em>? <em>microdon curvatus</em>, previously found only in the Canadian Arctic. This is the youngest Silurian graptolite record in south-western Gondwana, constituting a useful global biostratigraphic marker. The fossil-bearing strata can, at least partially, be correlated with the latest Silurian <em>Uncinatograptus birchensis</em> Zone, and can be referred to the latest Pridolian in accordance with evidence from the co-occurring brachiopod assemblage, as well as from conodont data from equivalent stratigraphic sections. Furthermore, the brachiopod faunal turnover recorded in the studied stratigraphic section potentially correlates with the Transgrediens Extinction Event, a biotic crisis not older than latest Pridolian. Evidence suggests that the brachiopod (and probably the trilobite) turnover and the concomitant biogeographic reconfiguration of provincialism of Gondwanan benthic faunas around the Silurian–Devonian boundary might be related to the aftermath of the Transgrediens Event.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100265"},"PeriodicalIF":0.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144694950","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fossil hypercalcified sponges; types, relationships and geological history","authors":"Stephen Kershaw ,&nbsp;Qi-Jian Li","doi":"10.1016/j.jop.2025.100289","DOIUrl":"10.1016/j.jop.2025.100289","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Hypercalcified sponges are poriferans with a calcareous skeleton secreted on and in the soft tissue. Living examples, and fossils of some such sponges in Mesozoic and Cenozoic strata, contain sponge spicules and can be classified within modern poriferan groups of the Classes Demospongiae and Calcarea, which are otherwise almost entirely soft-bodied. However, other fossil forms, largely Palaeozoic archaeocyaths, stromatoporoids and chaetetids, lack spicules, so their classification relies on the calcareous skeleton alone. Because of these discrepancies, although the hypercalcified skeleton is useful for low-level taxonomy in fossils, it has no proven phyletic value, so the systematic position of non-spiculate forms is problematic. Thus the hypercalcified skeleton has for many years been considered a grade of organisation of the skeleton, and the terms archaeocyath-grade, stromatoporoid-grade, chaetetid-grade, sphinctozoan-grade and inozoan-grade are applicable. Nevertheless, archaeocyaths have also been separated as a class, by sponge researchers, creating a quandary about their taxonomic status. Two older classification terms are redundant: sclerosponges (previously a class of all hypercalcified sponges) and pharetronids (previously a subgroup now divided into sphinctozoans and inozoans). Pharetronids are polyphyletic within the Demospongiae and Calcarea.&lt;/div&gt;&lt;div&gt;Hypercalcified sponges’ history began with archaeocyaths (early-mid Cambrian). Then, prominence of stromatoporoid-grade in the mid-Palaeozoic, and chaetetid-grade in the Carboniferous, was followed by a sparse record in both groups for much of the Permian while sphinctozoan- and inozoan-grades expanded. The Mesozoic has a good record of sphinctozoans, inozoans, stromatoporoids and chaetetids up to the end-Cretaceous. Cenozoic forms are uncommon but 19 genera of modern-day demosponges and calcarean sponges encompass all five grades, versus the total modern sponge diversity of 680 genera. Hypercalcification is diverse in modern sponges, involving aragonite, high-Mg and low-Mg calcite; ancient groups reflect this range in their variation of preservation (including widespread diagenetic alteration) that makes understanding of hypercalcification mechanisms problematic.&lt;/div&gt;&lt;div&gt;Presence of hypercalcified sponges from Early Cambrian to modern times, with short breaks associated with extinction events, demonstrates that hypercalcification was an iterative evolutionary feature. For example, the stromatoporoid-grade appeared in Early to Mid-Ordovician and continued through geological history to modern representatives, albeit with taxa turnover through time. Stromatoporoids are traditionally viewed as becoming extinct at the end-Devonian Hangenberg event, but because they form a grade, rather than a proven phyletic group, discussion of the extinction of stromatoporoids as a group has little meaning; it is more appropriate to consider that certain sponge taxa, possessing stromatoporoid","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100289"},"PeriodicalIF":2.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145323833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Linking rapid grain size coarsening in the Neogene Xiyu Conglomerates to gravel–sand transitions in modern northern Tian Shan rivers: Evidence of shared origins from field and provenance investigations","authors":"Chao Li ,&nbsp;Zhi-Yuan He ,&nbsp;Sheng-Li Wang ,&nbsp;Yan Chen ,&nbsp;Yi-Fan Shi ,&nbsp;Guo-Hui Chen ,&nbsp;Shao-Wen Liu ,&nbsp;Yun-Jian Li ,&nbsp;Fei Xue ,&nbsp;Wen-Bo Rao","doi":"10.1016/j.jop.2025.100293","DOIUrl":"10.1016/j.jop.2025.100293","url":null,"abstract":"<div><div>The Cenozoic uplift of the Central Asia Tian Shan Mountains has driven significant subsidence in the foreland basins along its northern and southern flanks, leading to the extensive deposition of the Late Cenozoic alluvial-gravel deposits at its piedmonts known as the Xiyu Conglomerates. At the base of these conglomerates, localized gravel deposition replaces sandstones vertically over tens of meters with a sharp increase in median grain size (D50) by c. 100-fold. However, the origin of the transition remains a subject of controversy, with multiple potential factors intricately linked to regional tectonics and climatic variations. To address this question, we investigated the grain size variations of modern riverbed sediments along six rivers and the Xiyu Conglomerates in two sections within the northern foreland area of Tian Shan Mountains. We observed a rapid gravel–sand transition (GST) along the present-day rivers, 20–50 km downstream from the outlet, as well as a sharp conglomerate–sandstone transition at the base of the Xiyu Conglomerates, both of which exhibit similar fining rates. Furthermore, a provenance investigation of the Jingou River basin, using heavy mineral assemblages and detrital zircon U–Pb ages, indicates consistent sources for both the Xiyu Conglomerates and modern riverbed sediments. The combined results suggest that the striking grain size changes observed in both the Xiyu Conglomerates and along these modern rivers from similar internal hydraulic processes within the piedmont rivers, specifically size-selective sorting controlled by the bimodal grain size distribution of sediments. This implies that the emergence of sharp grain size transitions in the vertical successions was a result of the continuous northward progradation of the GST in the basin, driven by the long-term northward thrusting of the Tian Shan Mountains, independent of sharp and specific changes in climatic or tectonic forcing events. The average northward migration rate of the GSTs is calculated to be 3.9 ± 0.2 mm/yr since c. 7.5 Ma along 85°30′E, and 7.6 ± 2.1 mm/yr since c. 2.1 Ma along 86°30′E. These rates closely reflect the long-term crustal shortening rates across the northern Tian Shan Mountains, and its increase may denote an acceleration of the shortening post-Miocene.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100293"},"PeriodicalIF":2.0,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145219191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Paleocene syncollisional deposits in Renbu, southern Tibet, China: New insights into the foredeep–wedge evolution of the Himalayan foreland","authors":"Zhen Wei ,&nbsp;Xiang-Hui Li ,&nbsp;Min-Jia Sun ,&nbsp;Xiao-Long Fan ,&nbsp;Jing-Yu Wang","doi":"10.1016/j.jop.2025.100263","DOIUrl":"10.1016/j.jop.2025.100263","url":null,"abstract":"<div><div>Understanding turbidites and olistostromes in the foredeep depozone is critical for deciphering foreland–orogenic wedge interactions. Despite the abundance of syncollisional deposits in the central Himalaya, current research lacks analysis of their depositional models in this context. Our study focuses on the Renbu Unit, a recently discovered Paleocene syncollisional deposits in Renbu, assessing its lithological composition, sedimentary environment, and provenance. The lower part of the Renbu Unit is characterized by fine-grained turbiditic sandstones, showcasing maximum depositional ages of ∼80 Ma. Contrarily, the upper part, composed of coarse-grained turbiditic sandstones, presents a maximum depositional age of ∼64 Ma. The sandstones sources vary from the recycled Xigaze forearc basin in the lower unit to the Gangdese arc in the upper unit. Hence, the lower Renbu Unit could equate to the Jiachala Formation, and the upper Renbu Unit could correspond to its eroded counterpart whose zircon geochronology fits the biostratigraphic data of the Jiachala Formation. This leads to a new depositional model suggesting near-contemporaneous deposition of the Zongzhuo mélange, Jiachala Formation, and the Renbu Unit in the foredeep, demonstrating events like the orogenic front's collapse and gravity flow deposition.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100263"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144657097","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Astronomically-paced lake-level changes on halite deposition during the Paleogene in the Huanggang Basin, East China","authors":"Cui-Yu Song ,&nbsp;Da-Wei Lü ,&nbsp;Wen-Tao Chen ,&nbsp;Munira Raji ,&nbsp;Bin Yang ,&nbsp;Zhen-Guo Ning ,&nbsp;Lu-Lu Tang ,&nbsp;Zhi-Hui Zhang","doi":"10.1016/j.jop.2024.12.008","DOIUrl":"10.1016/j.jop.2024.12.008","url":null,"abstract":"<div><div>The formation of halite in continental basins is intimately linked to lake-level changes. Current research has revealed the connection between lake-level variations and astronomical forcing on a million-year scale. Other studies have also highlighted the influence of orbitally-induced climate cycles on halite deposition. However, our understanding of the impact of astronomically-paced lake-level changes on halite formation remains constrained. The Paleogene Dawenkou Formation in the Huanggang Basin of East China provides a continuous salt-bearing sedimentary record to investigate the lake-level changes in halite deposition. Lake-level fluctuations reconstructed by sedimentary noise modeling for the Middle and Upper members of the Dawenkou Formation indicate that the lake-level variations in the Huanggang Basin were linked to astronomical forcing with periods of ∼2.4 Myr, ∼1.2 Myr and/or ∼100 kyr. Our results suggest that astronomical forcing, as a driver of lake-level variations, may have had an impact on halite deposition during the Paleogene. In the initial stage of halite formation within the Middle Member of the Dawenkou Formation, reduced heat and moisture transport during the ∼1.2 Myr obliquity minima resulted in low lake levels in mid-to-high latitudes. The prolonged droughts caused by the low amplitude of ∼2.4 Myr eccentricity created conditions more favorable for the development of thicker layers of halite. Subsequently, in the next halite-forming stage, a larger amplitude of ∼2.4 Myr eccentricity led to a more humid climate. Warm/dry winters and cool summers paced by the ∼100 kyr orbital eccentricity minima resulted in enhanced evaporation, relatively lower lake levels, and thinner halite deposition. Nevertheless, the possible transgressions may have contributed to complicated phase relationship between the lake-level change cycles and orbital cycles. This study offers an opportunity to delve deeper into the mechanism of halite deposition by objectively reconstructing lake levels using sedimentary noise modeling.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100250"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144720963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Systematic palaeontology and biostratigraphy of early Oligocene larger benthic foraminifera, offshore, southern Iran (Asmari Formation)","authors":"Mohsen Yazdi-Moghadam ,&nbsp;Mehdi Sarfi ,&nbsp;Mehrdad Naghusi ,&nbsp;Mohammad Sharifi ,&nbsp;Reza Aharipour ,&nbsp;Houshang Khairy","doi":"10.1016/j.jop.2024.08.013","DOIUrl":"10.1016/j.jop.2024.08.013","url":null,"abstract":"<div><div>The biostratigraphic aspects of the lower Oligocene carbonates of the Asmari Formation, offshore, southern Iran were analyzed, providing a high-resolution dating based on recovered larger benthic foraminifera. As a part of the Tethyan Seaway, the Asmari Formation is located between the Western and Eastern Tethys Oceans. The fauna is dominated by both hyaline perforated and porcelaneous forms, including <em>Nummulites fichteli</em>, <em>Operculina complanata</em>, <em>Eulepidina formosoides</em>, <em>Austrotrillina paucialveolata</em>, and <em>Peneroplis thomasi</em>. Data from the Asmari Formation show a high similarity to occurrences from the Western Tethys. The co-existence of <em>Nummulites fichteli</em> and <em>Eulepidina formosoides</em> indicates SBZ 22A Subzone referring to a short time span restricted to late Rupelian.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100252"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cyclic gravity flow deposits constrained by alternating dry/wet climates in a middle‒late Eocene saline lake, Jianghan Basin, Hubei Province, China","authors":"Tao-Yuan Ge ,&nbsp;Xiang-Xin Kong ,&nbsp;Zai-Xing Jiang ,&nbsp;Shi-Qiang Wu ,&nbsp;Mathieu Schuster ,&nbsp;Guilherme Bozetti","doi":"10.1016/j.jop.2025.100257","DOIUrl":"10.1016/j.jop.2025.100257","url":null,"abstract":"<div><div>Lacustrine sediments serve as valuable archives of extreme events and past environmental changes. However, the formation mechanisms and distribution patterns of gravity flow deposits in inland hypersaline lakes under climatic controls remain underexplored. In the Eocene Jianghan Basin, rhythmic strata influenced by climatic cycles provide a unique opportunity to investigate the relationship between gravity flow deposits and paleoclimate. According to core descriptions, thin section analysis, logging data, and grain size analysis, seven lithofacies and four lithofacies associations related to gravity flow deposits were identified. Frequent turbidity flows, primarily flood-induced gravity flows, are widely distributed in the saline lake. Proximal gravity flow deposits are characterized by thick, massive sandstones with minimal mud debris, occasionally featuring deformed lamination and scoured bases. Distal gravity flow deposits comprise clast-bearing massive sandstones, planar laminated sandstones, and graded siltstones. Paleoclimate analysis, based on trace elements and rock salt thickness, reveals a strong linkage between gravity flow deposits and climatic cycles. Correlations were established by systematically identifying short-term base-level cycles, which were subsequently grouped into medium-term base-level cycles through stacking pattern analysis. Short-term base-level changes, corresponding to stable climatic cycles, are marked by rhythmic salt layers. In contrast, medium-term base-level cycles, controlled by orbital periods, govern the deposition of gravity flow deposits. Under arid climatic conditions, reduced vegetation coverage and pronounced temperature variations lead to intensified erosion and increased suspended particle concentration. The deposition of sandstone layers is more substantial, and the frequency of turbidity flows is significantly higher under arid climatic conditions compared to humid climatic conditions. This research highlights how climatic cycles influence gravity flow deposits in hypersaline lake environments.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100257"},"PeriodicalIF":2.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144721249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The first record of the pachycormid fish Bonnerichthys in Eurasia marks a global distribution of Late Cretaceous suspension-feeding giants","authors":"Alina Kanarkina ,&nbsp;Nikolay G. Zverkov ,&nbsp;Evgeny V. Popov","doi":"10.1016/j.jop.2025.100255","DOIUrl":"10.1016/j.jop.2025.100255","url":null,"abstract":"<div><div>The giant Late Cretaceous suspension-feeding pachycormid <em>Bonnerichthys</em> has puzzled researchers since it was named, as its geographic distribution is confined to the USA, which contrasts with other widespread Jurassic and Cretaceous pachycormid genera. Here we describe fin fragments of <em>Bonnerichthys</em> from the Campanian of European Russia. The fins have a characteristic structure of the anterior edge, which is strongly thickened with its leading edge forming a sharp but irregularly excavated keel; internally the fins have a specific ossification with wedge-shaped structure between the rays. These features are autapomorphic of <em>Bonnerichthys</em> and thus allow for positive assignment of the Russian specimens to this genus. This is the first direct evidence of the presence of <em>Bonnerichthys</em> outside the USA, which solves the mystery of its seemingly restricted distribution and highlights that all large suspension-feeding pachycormids were cosmopolitan during their Jurassic and Cretaceous evolutionary history.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100255"},"PeriodicalIF":0.0,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}