Cretaceous Research最新文献

{"title":"Detrital zircon U–Pb geochronology of the trench-fill sandstone on the Cretaceous Shimanto accretionary complex in SW Japan: Implications for provenance and igneous activity in the eastern edge of East Asia","authors":"Tetsuya Tokiwa ,&nbsp;Yusuke Shimura ,&nbsp;Hiroshi Mori","doi":"10.1016/j.cretres.2024.106012","DOIUrl":"10.1016/j.cretres.2024.106012","url":null,"abstract":"<div><div>Cretaceous igneous rocks are widely distributed in the East Asian margin, and their formation is due to the large-scale migration of igneous activity areas from the continental interior to near the subduction margin. Detrital zircon U–Pb ages of trench-fill sandstones of the Shimanto accretionary complex in the Akaishi Mountains of southwest Japan can provide information on eroded igneous rocks, and their location at the eastern edge of East Asia makes them essential for better understanding the intensity and migration of the igneous activity. As a result of the dating, the Cretaceous zircons in the trench-fill sandstones were found to increase dramatically in the middle Cretaceous and to be abundant in the Late Cretaceous. In addition, these large amounts of Cretaceous zircons were found to be derived from igneous rocks such as the Abukuma Granites and Ryoke Granites distributed in the proto-Japan arc. These results indicate that migration of igneous activity from the continental side reached the eastern edge of East Asia in the middle Cretaceous and that large-scale igneous activity continued to occur in the eastern edge of East Asia until the Late Cretaceous. Thus, the detrital zircon age spectra in trench-fill sediments provide a clear picture of the degree of igneous activity in the source area and migration of the igneous activity on active continental margins.</div></div>","PeriodicalId":55207,"journal":{"name":"Cretaceous Research","volume":"166 ","pages":"Article 106012"},"PeriodicalIF":1.9,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142426920","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 maritime location reduced palynofloral turnover and extirpation across the end Cretaceous boundary interval on the west coast of Canada","authors":"Nidhi U. Patel ,&nbsp;Sandy M.S. McLachlan ,&nbsp;Jennifer M. Galloway ,&nbsp;David R. Greenwood ,&nbsp;Vera Pospelova","doi":"10.1016/j.cretres.2024.106011","DOIUrl":"10.1016/j.cretres.2024.106011","url":null,"abstract":"<div><div>A well-preserved suite of ∼163 spore-pollen taxa from a recently discovered K/Pg interval within the maritime Oyster Bay Formation, Vancouver Island, British Columbia, Canada, reveals a pattern of floral turnover across the boundary event with local extirpations of ∼15 % of Cretaceous taxa. Along the margin of the eastern North Pacific, a shift occurred in near-coastal vegetation composition from uppermost Cretaceous diverse fern and bryophyte-dominated communities to Danian conifer-dominated forests with a fern understory. The ‘fern spore spike’ common in other K/Pg records was not detected within the sandstone to mudstone sequence. Spore-pollen assemblages preserved herein align with those of the Continental Margin floristic province. Palm pollen is noteworthy in the studied sections including <em>Arecipites</em> spp. (aff. Arecaceae), <em>Spinizonocolpites</em> spp. (aff. <em>Nypa</em>) and <em>Pandaniidites typicus</em> (aff. <em>Pandanus</em>) suggesting a warm, frost-free, sub-tropical climate prevailed across the K/Pg interval. The presence of numerous endemic spore-pollen taxa is indicative of geographic isolation from the North American Western Interior. Maritime climate buffering along the west coast of North America contributed to microrefugia permitting greater stability in terrestrial plant communities than in continental regions.</div></div>","PeriodicalId":55207,"journal":{"name":"Cretaceous Research","volume":"166 ","pages":"Article 106011"},"PeriodicalIF":1.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142426921","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":"First discovery of dinosaur tracks from the Lower Cretaceous Duoni Formation in eastern Tibet, China","authors":"Yangui Li ,&nbsp;He Zhao ,&nbsp;William J. Foster ,&nbsp;Yue Yu ,&nbsp;Lida Xing ,&nbsp;Qiang Ye ,&nbsp;Chuanshang Wang ,&nbsp;Huazhou Yao","doi":"10.1016/j.cretres.2024.106009","DOIUrl":"10.1016/j.cretres.2024.106009","url":null,"abstract":"<div><div>Dinosaurs are known to have been abundant and diverse in eastern Tibet, and roamed the region from the Early Jurassic to the Late Cretaceous. Even though the evidence of dinosaurs is known throughout this interval, there are still many stratigraphic gaps that lack evidence, such as the Upper Jurassic and the Lower Cretaceous successions. Here, we report a new dinosaur tracksite from the Lower Cretaceous Duoni Formation of Basu County, where 28 track-bearing surfaces were discovered, which document a flourishing dinosaur community. Of these, three track layers with a high abundance of dinosaur tracks are described here, including sauropod, ornithopod and theropod trackways. These tracks suggest a possible exchange of trackmakers between this region and with adjacent areas of East Asia. The trackmakers' size, gait, and speed were inferred. The paleoenvironment is interpreted as ephemeral lakes bordered by conifer dominated forests. Palynological analysis conducted along the Duola stratigraphic section suggests that the tracksite is Aptian-Albian (Lower Cretaceous) in age, and the paleoclimate of the Basu area was relatively warm and dry.</div></div>","PeriodicalId":55207,"journal":{"name":"Cretaceous Research","volume":"166 ","pages":"Article 106009"},"PeriodicalIF":1.9,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reassessment of a theropod ilium from the Kem Kem beds of Morocco and the evolution of ilia in Spinosauridae","authors":"Adun Samathi","doi":"10.1016/j.cretres.2024.106007","DOIUrl":"10.1016/j.cretres.2024.106007","url":null,"abstract":"<div><div>A theropod ilium MHNM KK04 from the Kem Kem Beds (Cenomanian) of Morocco was originally described as an abelisaurid. It is here reinterpreted as a spinosaurine spinosaurid. The phylogenetic relationships of MHNM KK04 were analyzed. A thorough and careful comparison between spinosaurids and abelisaurids was made. The Kem Kem ilium was identified as a spinosaurid based on the similarity to the <em>Spinosaurus aegyptiacus</em> neotype and the MSNM V6900 specimen (i.e., the lateral wall of brevis fossa is taller than the medial wall, the ventral margin of the postacetabular blade is straight, and the ventral margin of postacetabular process is posteroventrally oriented). However, MHNM KK04 is slightly different from the ilium of the <em>Spinosaurus aegyptiacus</em> neotype (i.e., the ilium dorsal margin is sub-horizontal to slightly anteriorly inclined, the dorsoventral height of the iliac blade at the postacetabular portion is approximately the same size as the blade height above the acetabulum, and the postacetabulum length is slightly longer than the ischial peduncle length). MHNM KK04, together with previous studies, shows that there were at least two morphotypes of spinosaurines in the Late Cretaceous of Kem Kem beds. Nevertheless, taphonomy, intraspecific or ontogenetic variation cannot be ruled out in the present work. This reclassification adds to the number of juvenile spinosaurines from the Kem Kem beds and provided evidence on the evolution of ilia in spinosaurids.</div></div>","PeriodicalId":55207,"journal":{"name":"Cretaceous Research","volume":"166 ","pages":"Article 106007"},"PeriodicalIF":1.9,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comment on «Microlepia burmasia sp. nov., a new fern species from mid-Cretaceous Kachin amber of norther Myanmar (Dennstaedtiaceae, Polypodiales) » [Cretaceous Research 143 (2023) 105417]","authors":"Wenyue Zhang","doi":"10.1016/j.cretres.2024.106010","DOIUrl":"10.1016/j.cretres.2024.106010","url":null,"abstract":"<div><div>“<em>Microlepia</em>” <em>burmasia</em> is a recently described eupolypod fern from mid-Cretaceous Burmese amber by Long et al. (2023). According to the latest taxonomic system of ferns, “<em>M</em>.” <em>burmasia</em> belongs to the Dennstaedtiaceae, Polypodiales. Discovery of “<em>M</em>.” <em>burmasia</em> means the origin of the genus can be pushed back by at least 99 Ma. The specimen provides new information on the floral diversity of the Kachin amber forest and new insight to the origin of <em>Microlepia</em> and Dennstaedtiaceae (Long et al., 2023). However, a careful review of the illustrations and descriptions of the sporangium and spore in the manuscript showed that the polar axial length and equatorial length of the spores were three to six times that of the spores in the extant and fossil <em>Microlepia</em> species, and nearly the same size as the sporangium, and the sporangium morphology and spore size are very different from that of any other polypod species. In an effort to further investigate the systematic position of “<em>Microlepia</em>” <em>burmasia</em>, its spore morphology and size were compared with those of the entire Dennstaedtiaceae and to all fern families possessing trilete spores. Comparative analyses reveal some similarities only with <em>Anemia</em> subgenus <em>Coptophyllum</em> (Anemiaceae). However, the sporangium morphology of “<em>Microlepia</em>” <em>burmasia</em> does not align with Anemiaceae. Given these discrepancies, it is recommended to reconsider the placement of “<em>Microlepia</em>” <em>burmasia</em> within Polypodiales and its systematic placement needs further study.</div></div>","PeriodicalId":55207,"journal":{"name":"Cretaceous Research","volume":"166 ","pages":"Article 106010"},"PeriodicalIF":1.9,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142315907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 unusual biofacies in a rocky shoreline succession of Vancouver Island, British Columbia, Canada: First record of Late Cretaceous coralline algae from the northeast Pacific region","authors":"James W. Haggart ,&nbsp;Ioan I. Bucur ,&nbsp;Raymond Graham ,&nbsp;Graham Beard","doi":"10.1016/j.cretres.2024.106008","DOIUrl":"10.1016/j.cretres.2024.106008","url":null,"abstract":"<div><div>Three common morphotypes of <em>Sporolithon</em> sp., as well as the peyssonneliacean red algae <em>Polystrata</em>, have been identified from Cretaceous clastic strata of Departure Bay, Vancouver Island, British Columbia. While coralline algae are known from the Cretaceous of Japan, they have not been recognized previously from the Cretaceous of the Pacific coast of North America. Mollusks associated with the coralline algae indicate an age of late early to early middle Campanian, corresponding to the time of maximum paleotemperature as represented in strata of the Nanaimo Group. The coralline algae are found in conglomerate and sandstone representing a basal transgressive facies of the Upper Cretaceous Nanaimo Group succession, resting unconformably on pillow basalts of the Upper Triassic Karmutsen Formation. This rocky shoreline facies is unusual in exhibiting extensive coralline algae packstone deposits. <em>Paleodictyon</em> is also found with the coralline algae, the first shallow-marine example of this trace fossil from the Cretaceous of the northeast Pacific region.</div></div>","PeriodicalId":55207,"journal":{"name":"Cretaceous Research","volume":"166 ","pages":"Article 106008"},"PeriodicalIF":1.9,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mosasaur (Reptilia, Mosasauridae) remains from the Upper Cretaceous of Colombia, including the first occurrence of the genus Globidens","authors":"Juan S. López-Rueda ,&nbsp;Michael J. Polcyn ,&nbsp;Johan Lindgren ,&nbsp;Luis E. Cruz-Guevara ,&nbsp;Andrés S. Rodríguez-Sañudo","doi":"10.1016/j.cretres.2024.105997","DOIUrl":"10.1016/j.cretres.2024.105997","url":null,"abstract":"<div><p>Isolated mosasaur teeth and vertebrae recovered from beds of the Guadalupe Group of central Boyacá, Colombia, are reported. A partial tooth crown identified as <em>Globidens</em> sp., found in the Labor-Tierna Formation (Maastrichtian), represents the first report of this genus from northern South America and its most equatorial occurrence. A tooth crown recovered from the Plaeners Formation (upper Campanian–lower Maastrichtian), represents the youngest record of the subfamily Plioplatecarpinae in Colombia. These occurrences collectively constitute the youngest record of the family Mosasauridae in Colombia and expand both the taxonomic diversity and biogeography of mosasaurids in northern South America.</p></div>","PeriodicalId":55207,"journal":{"name":"Cretaceous Research","volume":"166 ","pages":"Article 105997"},"PeriodicalIF":1.9,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142162624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Review of two marine vertebrate assemblages from the Arauco Basin (central Chile) reveals diversity changes throughout the Maastrichtian","authors":"Rodrigo A. Otero","doi":"10.1016/j.cretres.2024.105996","DOIUrl":"10.1016/j.cretres.2024.105996","url":null,"abstract":"<div><p>Upper Cretaceous vertebrate records from Chile are mostly known by historical mentions with unknown repositories and uncertain stratigraphic provenance. This contribution reviews and complements two marine vertebrate assemblages from the Upper Cretaceous of central Chile, which were part of the ancient Arauco Basin. The oldest assemblage (lower Maastrichtian) comprises abundant condrichthyans referred to <em>Carcharias gracilis</em>, <em>Odontaspis</em> cf. <em>winkleri</em>, <em>Scapanorhynchus</em> sp., <em>Centrophoroides appendiculatus</em>, <em>Squatina</em> sp., <em>Cretorectolobus</em> sp., Orectolobidae indet., <em>Paraorthacodus</em> sp., <em>Ischyrhiza chilensis</em> and <em>Biropristis landbecki</em>, which adds to the previously reported occurrences of <em>Echinorhinus</em> sp. and <em>Myledaphus araucanus</em>. In addition, chimeroids referred to as <em>Edaphodon kawai</em> and remains of a leatherback turtle referable to <em>Mesodermochelys</em> sp. are here described, the latter being its first occurrence outside Japan. The younger assemblage (upper Maastrichtian) includes similar chondrichthyans and a higher diversity of marine reptiles, including plesiosaurians (<em>Aristonectes</em> sp., Aristonectinae indet., and Elasmosauridae indet.), sea turtles (Pancheloniidae indet.) and diverse mosasaurs (<em>Halisaurus</em> sp., Tylosaurinae indet., and the first local occurrence of Plioplatecarpinae indet.). Throughout the Maastrichtian, the local marine vertebrates likely suffered a declination in abundance but a rise in diversity, with evidence of a marked alteration in middle levels of the trophic web during the upper Maastrichtian. This fauna shows a main influence from the northern hemisphere (especially from the Western Interior Sea), acquiring a more marked Weddellian influence during the end of the Maastrichtian. The studied material allows a better understanding of the Upper Cretaceous vertebrate marine fauna in lower latitudes of the southeastern Pacific.</p></div>","PeriodicalId":55207,"journal":{"name":"Cretaceous Research","volume":"166 ","pages":"Article 105996"},"PeriodicalIF":1.9,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0195667124001691/pdfft?md5=77dc8cdd68bd74e43fe53339430715af&pid=1-s2.0-S0195667124001691-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142162615","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 new late-diverging non-hadrosaurid hadrosauroid (Dinosauria: Ornithopoda) from southwest China: Support for interchange of dinosaur faunas across East Asia during the Late Cretaceous","authors":"Hui Dai ,&nbsp;Qingyu Ma ,&nbsp;Can Xiong ,&nbsp;Yu Lin ,&nbsp;Hui Zeng ,&nbsp;Chao Tan ,&nbsp;Jun Wang ,&nbsp;Yuguang Zhang ,&nbsp;Hai Xing","doi":"10.1016/j.cretres.2024.105995","DOIUrl":"10.1016/j.cretres.2024.105995","url":null,"abstract":"<div><p>A non-hadrosaurid hadrosauroid, <em>Qianjiangsaurus changshengi</em> gen. et sp. nov., is named and described here based on an incomplete, partially articulated skeleton from the top of the Upper Cretaceous Zhengyang Formation in Qianjiang District, Chongqing Municipality, southwest China. The skeleton displays a transitional morphology between non-hadrosaurid hadrosauroids and hadrosaurids. The diagnosis of the taxon is therefore defined as a unique combination of characters, including a series of plesiomorphic features typical of non-hadrosaurid hadrosauroids, some apomorphic features common among hadrosaurids but rarely reported in non-hadrosaurid hadrosauroids, and a probable autopomorphy, namely the fan-shaped prepubic process of the pubis strongly anteroposteriorly constricted and dorsoventrally expanded, with the length/height ratio of ∼0.79. Phylogenetic analysis recovers a sister-taxon relationship between <em>Qianjiangsaurus</em> and <em>Plesiohadros</em> outside of Hadrosauridae, and the clade consisting of the two taxa is positioned higher on the tree than <em>Gobihadros</em> and <em>Gilmoreosaurus</em>, but below the clade of <em>Telmatosaurus</em> + <em>Tethyshadros</em>, <em>Eotrachodon</em> and <em>Zhanghenglong</em>. Combining the morphological data with the phylogenetic topology identifies <em>Q. changshengi</em> as a late-branching non-hadrosaurid hadrosauroid. Given that the age assemblage of the eight hadrosauroids closely related to <em>Qianjiangsaurus</em> in phylogeny spans the Santonian–early Maastrichtian time interval, the top of the Zhengyang Formation, from which <em>Qianjiangsaurus</em> is recovered, is possibly restricted to the late Late Cretaceous in age. Hierarchical clustering of twelve hadrosauroid-bearing dinosaur assemblages from the Late Cretaceous deposits of Asia shows a strong correlation between the Zhengyang Formation and the Djadokhta and Baruungoyot formations in Mongolia that supports coeval interchange of dinosaur faunas across East Asia.</p></div>","PeriodicalId":55207,"journal":{"name":"Cretaceous Research","volume":"166 ","pages":"Article 105995"},"PeriodicalIF":1.9,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142137470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tracking environmental changes in an Early Cretaceous epicontinental sea: Sedimentology and geochemistry of the Romualdo Formation (Araripe Basin, NE Brazil)","authors":"Laís de Oliveira Ferreira ,&nbsp;Victor Eletherio Chagas ,&nbsp;Fabia Emanuela Rafaloski Bobco ,&nbsp;Danielle Cardoso de Souza ,&nbsp;Victor Matheus Joaquim Salgado-Campos ,&nbsp;Daniel Sedorko ,&nbsp;Manuely Neves ,&nbsp;Luís Fernando Silveira ,&nbsp;João Graciano Mendonça Filho ,&nbsp;Bruno César Araújo ,&nbsp;Leonardo Borghi","doi":"10.1016/j.cretres.2024.105986","DOIUrl":"10.1016/j.cretres.2024.105986","url":null,"abstract":"<div><p>The Early Cretaceous geological record contains evidence of major and abrupt global environmental changes. Understanding the past water-column redox fluctuations and paleoenvironmental evolution of Early Cretaceous environments is, therefore, pivotal for a better comprehension of this period as a whole. In this sense, to investigate the processes that modulated the deposition and preservation of the Romualdo Epicontinental Sea sediments (Aptian–Albian record of the Araripe Basin, Brazil), we present a multi-proxy study using samples from a new borehole drilled in the central area of the Araripe Basin. To unravel the origin, evolution, and demise of this shallow sea, a sedimentological and geochemical characterization was applied. We combine facies association, trace-fossil and petrographic analyses, bulk chemical data (<em>p</em>XRF), TOC and IR quantification (total organic carbon and insoluble residue, respectively), and SEM-EDS images. We identified twelve lithofacies that were grouped into four facies associations. The onset of the deposition of the Romualdo Formation is characterized by the transition from a fluvio-deltaic environment (FA-1) to an epicontinental sea (FA-2) that prevailed and further shifted into a deltaic environment (FA-3). The uppermost facies association (deltaic-fluvial; FA-4) reveals a continentalization process and the demise of the shallow sea. The variations of geochemical proxies were examined to assess terrigenous supply, salinity, redox conditions of bottom water, and primary bioproduction. Based on these proxies, we determined five chemostratigraphic units (U-A to U-E) that revealed a dynamic interplay between organic matter accumulation, paleoenvironmental shifts, and redox conditions. Our results demonstrate that the influx of nutrients from continental sources fostered pulses of biological productivity that, coupled with the low-oxygen environment, resulted in the preservation of organic-rich rocks (high TOC horizons). Notably, the enrichment of redox-sensitive trace elements (RSTEs) suggests that these organic-rich rocks were deposited under euxinic/oxygen-depleted environmental conditions, demonstrating that substantial variations in oxygen levels occurred. Overall, geochemical fluctuations indicate that climatic conditions and siliciclastic input primarily drove the lithofacies variation and organic matter accumulation. Lastly, the results provide constraints on the driving mechanisms that allowed the preservation of organic-rich mudstones of the Romualdo Formation, which is particularly relevant for other studies investigating similar processes in past epicontinental seas.</p></div>","PeriodicalId":55207,"journal":{"name":"Cretaceous Research","volume":"166 ","pages":"Article 105986"},"PeriodicalIF":1.9,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142148853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}