Journal of Palaeogeography最新文献

{"title":"Rhodoliths and trace fossils record stabilization of a fan-delta system: An example from the Mio-Pliocene deposits of Gran Canaria (Canary Islands, Spain)","authors":"Ana Cristina Rebelo ,&nbsp;Alfred Uchman ,&nbsp;Markes E. Johnson ,&nbsp;Carlos S. Melo ,&nbsp;Juana Vegas ,&nbsp;Inés Galindo ,&nbsp;Eduardo J. Mayoral ,&nbsp;Ana Santos ,&nbsp;Alberto González-Rodríguez ,&nbsp;Julio Afonso-Carrillo ,&nbsp;Sérgio P. Ávila ,&nbsp;Esther Martín-González","doi":"10.1016/j.jop.2025.100266","DOIUrl":"10.1016/j.jop.2025.100266","url":null,"abstract":"<div><div>Fan-delta systems are geomorphological structures and sedimentary records seldom preserved on oceanic volcanic islands. The generally coarse-grained deposits belonging to the Las Palmas Detritic Formation (Mio-Pliocene) at the Las Rehoyas section, NE part of Gran Canaria Island (Canary Islands, Spain), contain abundant but relatively small rhodoliths, non-nucleated, in partly bioturbated (<em>Skolithos</em> ichnofacies) sand-dominated strata. This section consists of four sedimentary units deposited in a fan-delta system that developed on a marine platform in the northeastern part of the island. The system was flooded during the late Miocene to early Pliocene, a non-eruptive phase on Gran Canaria Island. Stabilization of the fan delta due to a relative rise in sea level enabled colonization by burrowing organisms and the development of rhodoliths, which were redeposited by storms from the lower shoreface–offshore to the foreshore–middle shoreface environment.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 4","pages":"Article 100266"},"PeriodicalIF":0.0,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144702253","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":"2025-06-18","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":"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":"2025-05-23","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}

{"title":"Glacial and postglacial interpretation of Late Paleozoic sedimentation in a tectonically active mountain front in Paganzo Basin, Argentina","authors":"Carina Colombi ,&nbsp;Pablo J. Alonso-Muruaga ,&nbsp;Allison Raeann Kusick ,&nbsp;John L. Isbell ,&nbsp;Nicholas D. Fedorchuk ,&nbsp;Carlos M. Alarcón ,&nbsp;Carlos O. Limarino","doi":"10.1016/j.jop.2025.100261","DOIUrl":"10.1016/j.jop.2025.100261","url":null,"abstract":"<div><div>The Guandacol Formation corresponds to glacial episode 4 of the “Late Paleozoic Ice Age” in western Gondwana. It represents the final glaciation of westernmost Gondwana and the beginning of deglaciation that swept across the supercontinent throughout the rest of the Paleozoic. A succession of transitional sedimentary facies associations characterizes the eastern outcrops of the Guandacol Formation. These facies associations are interlayered with several deposits of mass-transport complexes (MTC) and present the occasional opportunity to conduct a deep-time analysis of the effect of tectonism in what is interpreted to be glacially-influenced deposits. Six sedimentary facies associations were recognized in the lower part of the Guandacol Formation. Facies association 1 (interbedded diamictites, sandstones, and mudstones) overlies MTC 1 and is interpreted as sedimentation into a marine glacially-influenced outwash fan. Facies association 2 (ponded interbedded sandstones, mudstones, and diamictites) was deposited as subaqueous underflows/turbidites and debris flows covering the irregular paleotopography of MTC 2. Facies association 3 (white medium- to coarse-grained sandstones and conglomerates) represents a small deltaic system. Facies association 4 (rhythmites with dropstones and sandstones) was deposited in a partially ponded water body resulting from the collapse and paleotopography of MTC 3. Facies association 5 (coarsening-upward cycles of mudstones and sandstones) was deposited in prodelta to delta front environments. Finally, facies association 6 (conglomerates, sandstones, and mudstones) corresponds to the subaerial deltaic platform. The evolution of depositional environments suggests three glacially-linked stages: Stage 1 — Initial retreat of the nearby ice masses (facies association 1); Stage 2 — Further retreat of glaciers and the progressive decoupling between ice masses and sea (facies associations 2 and 3); and Stage 3 — Postglacial sedimentation dominated by deltaic progradation during highstand conditions (facies associations 4 to 6). The importance of the paleogeographic context is emphasized in which the tectonism triggered recurrent events of MTC that continually modified the topography and sedimentary patterns, interrupting and complicating the stratigraphy of the interpreted glacial and postglacial sedimentation.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 3","pages":"Article 100261"},"PeriodicalIF":0.0,"publicationDate":"2025-05-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144481056","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":"Southern Tethys shelf evolution around the Cenomanian–Turonian OAE2: The Saharan Atlas (Algeria) depositional model","authors":"Madani Benyoucef ,&nbsp;Marcin Krajewski ,&nbsp;Mohamed Lassad Guendouz ,&nbsp;Mohammed Adaci ,&nbsp;Ashley Gumsley ,&nbsp;André Piuz ,&nbsp;Djamila Zaoui ,&nbsp;Imad Bouchemla ,&nbsp;Mariusz Salamon","doi":"10.1016/j.jop.2024.07.006","DOIUrl":"10.1016/j.jop.2024.07.006","url":null,"abstract":"<div><div>The present work, based on lithostratigraphy and biostratigraphy, is focused on ammonites, microfacies, and chemostratigraphic study (δ¹³C and δ¹⁸O) of the late Cenomanian–early Turonian sequence in the El Bayadh area (Saharan Atlas, Algeria). Five informal stratigraphic units (units 1 to 5) have been defined within the Rhoundjaïa Formation, which is subdivided into four ammonite biozones: the <em>Neolobites vibrayeanus</em>, the <em>Metoicoceras geslinianum</em>, the <em>Vascoceras cauvini</em>, and the <em>Choffaticeras sinaiticum</em> zones. The Cenomanian–Turonian boundary (CTB) is located at the limit between units 2 and 3. Field data and microscopic analysis have resulted in the recognition of fourteen microfacies types (MT 1 to MT 14) that are described in terms of depositional environments, and grouped into six main limestone and limestone–marl facies associations (FA 1–6), representing two different palaeosettings: (i) open shelf/ramp-type carbonate platform and (ii) isolated carbonate platform. The sequence stratigraphic analysis revealed two third-order depositional sequences (DS1 and DS2) covering a period of about 2.8 million years. The depositional model for the uppermost Cenomanian shows the presence of a rudist- and microbial-rich isolated carbonate platform, away from terrigenous influence, and surrounded by deep-water open shelf facies. The comparison of the isotopic fluctuation profile with those of various marine sites in the Tethyan Ocean shows synchronous global events.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 334-369"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869229","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":"Sedimentary system and palaeogeographic evolution of Ordos Basin, northern China","authors":"Yan-Qin Guo ,&nbsp;Bai-Qiang Li ,&nbsp;Bo Li ,&nbsp;Wen-Hou Li ,&nbsp;Hong-Xia Cao ,&nbsp;Yun Liao ,&nbsp;Zhen-Zhen Wu ,&nbsp;Shi-Xiang Fei ,&nbsp;Qian Zhang ,&nbsp;Qiang Chen ,&nbsp;Ruo-Gu Wang ,&nbsp;Yao Ma ,&nbsp;Zhen Yuan ,&nbsp;Zhi-Chao Li ,&nbsp;Sheng Fu","doi":"10.1016/j.jop.2025.01.002","DOIUrl":"10.1016/j.jop.2025.01.002","url":null,"abstract":"<div><div>Extensive work on outcrops and drilling wells in the Ordos Basin, northern China, has been carried out over the past decades to study its depositional systems. Investigation of depositional environments, lithology, sedimentary structures, and fossils in the basin reveals that during the Changchengian and Jixianian periods, the depositional system transformed from the continental-nearshore environment to carbonate tidal flat. From the deposition period of Xinji to the Zhushadong formations, the western and southern margin of the basin evolved from sand flat to dolomite flat. The open platform dominated the basin during the deposition period from Mantou to the Sanshanzi formations. From the deposition period of Yeli to the Liangjiashan formations, the eastern and southern margins of the basin evolved from argillaceous dolomitic flat to dolomitic flat. The large-scale transgression in the deposition period of Majiagou Formation resulted in extensive shallow-water epicontinental deposits. In the deposition period of Fengfeng Formation, the western margin of the basin was dominated by platform margin slope and continental slope-trough deposits, while the southeastern and southern parts were mainly open-platform deposits. During the deposition period of Pingliang Formation, shoal deposits occurred on the platform margin in the southern part of the basin. During the deposition period of Beiguoshan Formation, the dominant open platform and platform foreslope deposits were only distributed in the southwestern corner of the basin. The Ordovician and Carboniferous strata were separated by a major unconformity and the Silurian to Devonian were missing in the basin. In the deposition period of Benxi Formation, a filling process and the deposition of tidal flat–lagoon–barrier island–shallow sea shelf occurred in the basin. During the deposition period of Taiyuan Formation, the range of the shallow sea-shelf sedimentation in the eastern part reduced. During the deposition period from Shanxi to the Zhifang formations, the delta and shallow lacustrine deposits developed. The depocenters migrated in different periods. From the deposition period of the Yanchang Formation to the Cretaceous, lacustrine, meandering rivers, braided rivers, and deltas dominated the basin. The maximum lacustrine transgression occurred in the deposition period of Chang 7 Member of the Yanchang Formation, which can be divided into 10 members with Chang 1 at the top and Chang 10 at the bottom. During the deposition period from Fuxian to the Anding formations, the meandering river, delta, and shallow lake deposits developed, and the depocenter of shallow lake varied. Deep lacustrine sediments developed in the deposition period of the Anding Formation. During the deposition period of the Fenfanghe Formation, alluvial fan deposits dominated, then transformed into a desert and shallow lake facies in the Cretaceous, which resulted in the shrinking of the depocenter.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 501-534"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869315","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":"A moderate elevation and warm-humid climate of the Wulan Basin, NE Tibetan Plateau in the Middle Miocene indicated by Pueraria macrofossils","authors":"Zhen-Dong Cao,&nbsp;San-Ping Xie,&nbsp;Li-Ming Liu,&nbsp;Xiao-Mei Li,&nbsp;Si-Hang Zhang,&nbsp;Yun-Zhe Zhang,&nbsp;De-Fei Yan","doi":"10.1016/j.jop.2024.08.012","DOIUrl":"10.1016/j.jop.2024.08.012","url":null,"abstract":"<div><div>The phased uplift of the Tibetan Plateau since the Cenozoic strongly changed the Asian topography and greatly impacted not only the regional but also the global climate. Being sensitive to past climate changes, fossil plants are proven pivotal bio-indicators that can infer the paleoclimate and paleoelevation of different Tibetan Plateau parts. However, the timing and mechanisms of the uplift in the northeastern Tibetan Plateau remain debated due to limited evidence from plant fossils and inconsistent results. In this investigation, <em>Pueraria</em> leaflet and pod fossils collected from the Miocene Upper Youshashan Formation of the Wulan Basin, northeastern Tibetan Plateau, are reported. The leaflet fossils are assigned as a new species: <em>Pueraria qinghaiensis</em> Zhen-Dong Cao et San-Ping Xie sp. nov., while <em>P. montana</em> is recognized as its nearest living relative; the pod fossils are assigned as <em>Pueraria</em> sp. The leaflet margins of <em>P. qinghaiensis</em> and other fossils found in the same layer indicate that <em>Pueraria</em> from the Wulan Basin likely lived in open habitats and sprawled at the waterside. Moreover, the climate of the basin apparently was warm and humid in the Middle Miocene, and the elevation was about 723–2398 m based on the ecological niche of <em>Pueraria</em>. The occurrence of these new <em>Pueraria</em> fossils from the Wulan Basin supports the view that the elevation of the northeastern Tibetan Plateau did not attain its present elevation during the Middle Miocene. Subsequently, the plateau's uplift caused a series of environmental transformations, including increased elevation, reduced temperature and precipitation, and the intensification of Asian monsoons, which altogether led to the regional disappearance of the <em>Pueraria</em> population in the Wulan Basin.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 413-430"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868998","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":"Depositional age and provenance of Triassic sedimentary succession from Northwestern México: Evidence from petrography and detrital zircon U–Pb geochronology","authors":"Erik Ramirez-Montoya ,&nbsp;Jayagopal Madhavaraju ,&nbsp;Rogelio Monreal ,&nbsp;Luigi Solari","doi":"10.1016/j.jop.2025.01.001","DOIUrl":"10.1016/j.jop.2025.01.001","url":null,"abstract":"<div><div>The sedimentary succession of the El Antimonio Group, which unconformably overlies the Permian (Guadalupian) Monos Formation, is well exposed in the Sierra del Álamo section, southwest of Caborca, Sonora, México. Here, this section is composed of the Triassic Santa Eduwiges (renamed from the previous Antimonio Formation) and Río Asunción and the Lower Jurassic Sierra de Santa Rosa formations. This study focuses on the provenance and geochronology of the Triassic formations. The sandstone of Santa Eduwiges and Rio Asuncion formations are classified from litharenite to arkose. On the QtFL diagram, sandstone samples plot in the orogenic, transitional continental and undissected arc fields. In contrast, on the QmFLt diagram, the samples are mainly concentrated in the mixed, transitional continental and quartzose recycled fields. Main zircon populations identified in this study are Triassic, Permian and Proterozoic. Proterozoic zircon grains are grouped into ∼1.8, 1.7, 1.6, 1.4 and 1.1 Ga populations whose primary sources are the crustal basement rocks of the Mojave Yavapai and Mazatzal provinces of southwestern North America, and Mesoproterozoic granitic plutons that intrude them. Permo-Triassic zircon grains may be sourced in magmatic arc rocks of this age that in southwestern North America is well presented in northwestern Sonora. The detrital zircon dated allows us to constrain maximum depositional ages for the Triassic Santa Eduwiges Formation of the El Antimonio Group: the youngest zircon grains from lowermost part (Sequence I) yielded an age of 252.64±1.98 Ma; zircon grains from its middle part (Sequence IV) yielded an age of 244.63±3.04 Ma and zircon grains from Sequence VI of the upper part of this unit yielded an age of 229.33±1.72 Ma. The El Antimonio Group was deposited in a forearc basin located south as a product of the Permo-Triassic continental magmatic arc that contributed much of the detritus to the early Triassic basin. During later stages of sedimentation in the Triassic basin, detritus was mostly sourced from the Proterozoic basement rocks.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 370-390"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143868996","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":"Astronomical forces as a potential cause for the end-guadalupian biotic crisis: A case study from central Alborz, Iran","authors":"Forough Abasaghi ,&nbsp;Rui Zhang ,&nbsp;Qing-Yong Luo ,&nbsp;Ren Wei","doi":"10.1016/j.jop.2024.12.007","DOIUrl":"10.1016/j.jop.2024.12.007","url":null,"abstract":"<div><div>The Middle Permian extinction event is considered one of the most devastating events of all Phanerozoic biotic crises, yet it is not fully understood and has attracted a lot of controversial comments. This event is found at the end of the Capitanian carbonate strata in the Ruteh Formation (late Wordian–Capitanian) at the Alborz Mountains in Iran. It is characterized by the decimation of marine organisms, particularly calcareous algae and microproblematic fossils. The current study attempts to interpret the cause of this crisis in the framework of astronomically-forced climatic changes. Based on cyclostratigraphy analysis, the evidence of the Milankovitch cycles, including long eccentricity, short eccentricity, obliquity, and precession are recorded in the Ruteh Formation succession. The establishment of a floating astronomical time scale using the long eccentricity cycles led to an estimation of a duration of 1.6 and 2.43 million years for the Wordian and Capitanian stages, respectively. Integrated facies studies and a sedimentary noise model indicate that the Ruteh Formation is composed of three ∼1.2 Myr sequences, corresponding to third-order sequences, and ten 405-kyr sequences, corresponding to fourth-to fifth-order sequences. The boundaries of the ∼1.2 Myr sequences indicate regression in sea level and low sedimentation rate. Considering the paleogeographic situation of the Alborz Mountains, the sedimentation of the Ruteh Formation in the Middle Permian was affected by the Inter-Tropical Convergence Zone and interactions between the ocean and atmosphere during the Pangea assemblage, leading to an increase in temperature. With the sum of these observations, we conclude that factors such as high temperature and a decrease in sedimentation rate created unfavorable conditions for the mentioned biota at the end of the Capitanian.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 603-628"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869267","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":"Origin and depositional environments of mounded, banded and bedded dolostones in the clastic deposits of the Paleoproterozoic Chuanlinggou Formation in Beijing, North China","authors":"Jin-Yi Wang,&nbsp;Zhen-Kui Jin,&nbsp;Hao Cheng,&nbsp;Ke-Bei Hua,&nbsp;Hao-Xuan Ran","doi":"10.1016/j.jop.2024.11.005","DOIUrl":"10.1016/j.jop.2024.11.005","url":null,"abstract":"<div><div>Various studies have indicated that microbes were involved in the precipitation of dolostones in the Proterozoic. The identification of ancient microbial dolostones remains challenging due to the rare preservation of microbe fossils. In this study, we found ancient microbial dolostones in Paleoproterozoic Chuanlinggou Formation in Beijing, North China, employing thin-section observations, trace and rare earth elements as well as carbon and oxygen isotope analyses to reveal the origin. The paleoenvironment has also been reconstructed. The results indicate that dolostones found in the Chuanlinggou Formation are formed through primary dolomite precipitation induced by cyanobacterial activity. These dolomitized geobodies exhibit various morphologies of mounded, banded and bedded, and all dolostones are microcrystalline textures. The geochemical characteristics of these dolostones show a relatively low δ¹⁸O value (average = −7.34‰), Fe(II) enrichment, Ce anomaly and comparable patterns of REY. The specific geomorphology (mounded, banded and bedded) and mottled structures of the dolostones indicate that they are formed through in-situ dolomite precipitation induced by cyanobacterial activity. The high Fe(II) content suggests a reducing environment, whereas the Ce anomaly indicates anoxic conditions within the water body. The REY patterns provide evidence for the microbial origin of the dolostones. These dolostones were formed in clastic off-shore shelf environments. The seawater was warm, normal in salinity, and the sea floor was slightly agitated to quiet and reducing. The geomorphology of the dolomitized geobodies changes from mounded to banded and bedded in correlation with depth increase and hydrodynamic energy decrease. This study may provide another type of environments for microbial dolostones and the geochemical characteristics of these dolostones may serve as a valuable reference for identifying similar ancient microbial dolostones.</div></div>","PeriodicalId":100819,"journal":{"name":"Journal of Palaeogeography","volume":"14 2","pages":"Pages 629-650"},"PeriodicalIF":0.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869268","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}