Palaeoworld最新文献

{"title":"Storm deposits and trace fossils of Xinji Formation (Cambrian Series 2) in the southern margin of North China Plate","authors":"Ming-Yue Dai ,&nbsp;Lan-Lan Han ,&nbsp;Yong-An Qi ,&nbsp;Yao-Gang Du ,&nbsp;Zhong-Lei Yin ,&nbsp;Song-Hua Chen ,&nbsp;Shi-Yun Qing","doi":"10.1016/j.palwor.2024.05.009","DOIUrl":"10.1016/j.palwor.2024.05.009","url":null,"abstract":"<div><div>The Xinji Formation (Cambrian Series 2) in the southern margin of the North China Plate developed typical siliciclastic storm deposits and abundant trace fossils. These deposits are characterized by essential indicators, such as erosional surfaces, lag deposits, blocky beddings, hummocky cross stratifications, horizontal or wavy beddings. Storm deposits in the study area are dominated by the development of hummocky cross stratifications, which is categorized into five storm deposit types based on the arrangement of different sedimentary units in the profile. These five types of storm deposits from I to V show the transition from proximal storm deposits to distal storm deposits, the gradual weakening of storm intensity, and the associated growth of quiescent intervals. The trace fossils are mainly developed in the sandstone-mudstone interbeds between storm events and include 14 ichnospecies in 11 ichnogenera: <em>Didymaulichnus</em> isp., <em>Gordia marina</em>, <em>Helminthopsis tenuis</em>, <em>Oldhamia radiata</em>, <em>Palaeophycus striatus</em>, <em>Palaeophycus tubularis</em>, <em>Phycodes</em> isp., <em>Planolites beverleyensis</em>, <em>Planolites montanus</em>, <em>Planolites punctatus</em>, <em>Skolithos</em> isp., <em>Taenidium</em> isp., <em>Torrowangea rosei</em>, <em>Treptichnus pedum</em>. By analyzing the ichnological index (burrow size, BPBI, ichnodiversity and ichnodisparity) from different storm deposits, it can be seen that from storm deposit type I to storm deposit type V, the ichnological index shows an increasing trend. Combined with the relationship between storm deposits and trace fossils, it is inferred that differences in storm intensity result in different colonization windows, and thus variations in ichnological index of preserved trace fossils. Based on the characteristics of storm deposits and distribution of trace fossils, the preservation forms of trace fossils under storm influence are explored.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 2","pages":"Article 100866"},"PeriodicalIF":1.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782014","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":"On the biostratigraphic relevance of a new record of a traversodontid cynodont in southern Brazil (Candelária Sequence, Upper Triassic)","authors":"Lívia Roese-Miron ,&nbsp;Pedro Henrique Dotto ,&nbsp;Thais Gotuzzo de Menezes Medina ,&nbsp;Átila Augusto Stock Da-Rosa ,&nbsp;Rodrigo Temp Müller ,&nbsp;Leonardo Kerber","doi":"10.1016/j.palwor.2024.05.008","DOIUrl":"10.1016/j.palwor.2024.05.008","url":null,"abstract":"<div><div>The Várzea do Agudo is an Upper Triassic site of the Candelária Sequence of Southern Brazil that boasts an extensive fossil record. It is assigned to the <em>Exaeretodon</em> subzone of the <em>Hyperodapedon</em> Assemblage Zone (AZ) (mid-late Carnian) mainly due to the prevalent presence of the traversodontid <em>Exaeretodon riograndensis</em> — up to now the sole traversodontid discovered at the site. In this study, we report the first record of the traversodontid <em>Siriusgnathus niemeyerorum</em> in the Várzea do Agudo site. The new specimen was excavated from the upper layers of the outcrop. Its identification as <em>S</em>. <em>niemeyerorum</em> is substantiated by diagnostic features such as a poorly developed interorbital depression, an inconspicuous suborbital process of the jugal, a not deeply concave base of the lambdoidal crest, the distal accessory labial cusp of the upper postcanines more labially oriented than <em>E</em>. <em>riograndensis</em>, and two upper incisors — so far, a trait autapomorphic to the species among traversodontids. The age of the type locality of <em>S</em>. <em>niemeyerorum</em> has been a subject of debate. Whereas the <em>Siriusgnathus</em>-bearing sites had been associated with younger levels than those of the <em>Hyperodapedon</em> AZ, the absence of index fossils hampered proper biostratigraphic approaches. The finding of a <em>S</em>. <em>niemeyerorum</em> specimen in the same site as <em>E</em>. <em>riograndensis</em> poses a challenging scenario for the biostratigraphy of the fossiliferous outcrops of the municipality of Agudo. It is noteworthy, however, that the new specimen was excavated above the layers yielding <em>E</em>. <em>riograndensis</em>. This raises the question of whether the fossiliferous stratum of the Várzea do Agudo site was deposited in a single event or in a short period, or if it reflects two different time horizons. In the case of the latter, the existence of early Norian sites with distinct faunal composition near the <em>Siriusgnathus</em>-bearing sites could imply the existence of an intermediate fauna between this AZ and the <em>Exaeretodon</em> subzone of the <em>Hyperodapedon</em> AZ, of which <em>S</em>. <em>niemeyerorum</em> would be a constituent. Considering this context, this study discusses the possible biostratigraphic implications of the new record for the biostratigraphy of the sites of the Candelária Sequence.</div></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"34 2","pages":"Article 100864"},"PeriodicalIF":1.7,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141782011","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":"Early Eocene marine microgastropods from the Zhupure Formation in Yadong, Southern Tibet, China","authors":"Xin-Fa Li ,&nbsp;Guo-Biao Li ,&nbsp;Christopher L. Garvie","doi":"10.1016/j.palwor.2022.12.011","DOIUrl":"10.1016/j.palwor.2022.12.011","url":null,"abstract":"<div><p>Numerous microgastropods are reported for from the Eocene (Ypresian) Zhepure Formation in Tüna, Yadong, Southern Tibet for the first time. Although most of the shells are incompletely preserved, the following eight species of benthic microgastropods are described and illustrated: <em>Eulimella</em> sp., <em>Odostomia</em> aff. <em>pakistanica</em>, <em>Monotygma</em> aff. <em>marcusseni</em>, <em>Syrnola</em> sp., Pyramidellidae (<em>Syrnola</em>?) sp., Pyramidellidae indet. sp., <em>Mathilda</em> (<em>Echinimathilda</em>) cf. <em>duogenta</em> and the new species <em>Turbonilla yadongensis</em> n. sp. As little is known about Paleogene microgastropod fauna in Tibet, the occurrence here could give further information on Cenozoic biostratigraphy of Southern Tibet, the paleoenvironment and late evolutionary history of eastern Tethyan realm. Based on this study of the little-known Eocene microgastropod assemblage, we demonstrate that a shallow marine environment existed during early Eocene in the Southern Tibet.</p></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"33 3","pages":"Pages 777-787"},"PeriodicalIF":1.7,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42094232","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":"First record of the latest Devonian ostracods from Xainza region, Tibet, China: implications on palaeoenvironment and palaeobiogeography","authors":"Jun-Jun Song ,&nbsp;Wen Guo ,&nbsp;Yu-Cong Sun ,&nbsp;Juan Ma ,&nbsp;Jia-Yuan Huang ,&nbsp;Yi-Chun Zhang ,&nbsp;Wen-Kun Qie","doi":"10.1016/j.palwor.2022.01.002","DOIUrl":"10.1016/j.palwor.2022.01.002","url":null,"abstract":"<div><p>Ostracods of the Devonian–Carboniferous transitional interval in the Lhasa Block are described for the first time at the stratotype section of the Chaguoluoma Formation, Xainza, Tibet. Fifty-three ostracod species of 19 genera are identified and figured including a new species <em>Bairdiacypris xainzaensis</em> n. sp. The ostracod fauna in the Chaguoluoma section may represent an age close to the Devonian–Carboniferous boundary. The benthic ostracods from the Chaguoluoma section belong to the Podocopid association (i.e., Eifelian Mega-Assemblage), which implies an offshore environment. Additionally, ostracods from the Chaguoluoma Formation show a high similarity to the Devonian taxa from South China, suggesting a close biogeographic affinity between the Lhasa Block and South China Plate. They are also compared to the ostracod faunas from Laurentia–Baltica, Gondwana, and Kazakhstan plates, which implies that ostracods could probably benefit from oceanic circulations and sea-level changes to experience faunal exchanges between peri-Gondwana and Laurentia–Baltica during the latest Devonian.</p></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"33 3","pages":"Pages 598-611"},"PeriodicalIF":1.7,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43937861","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":"Zonation and biofacies of the Early Mississippian conodonts from Baoshan, Yunnan, Southwest China","authors":"Wen-Qi Wang,&nbsp;Xiang-Dong Wang,&nbsp;Ke-Yi Hu","doi":"10.1016/j.palwor.2023.03.010","DOIUrl":"10.1016/j.palwor.2023.03.010","url":null,"abstract":"<div><p>Early Mississippian Yudong and Shihuadong formations are well exposed in the Yudong I and Yudong II sections, Shidian, Baoshan, western Yunnan, Southwest China. Abundant and diverse conodonts are recovered from the two formations. A total of 29 species/subspecies belonging to 10 genera are identified. The <em>Siphonodella</em> and <em>Scaliognathus anchoralis</em>-<em>Gnathodus pseudosemiglaber</em> zones are recognized. Through cluster analysis, one conodont biofacies, <em>Polygnathus</em> biofacies, and two subbiofacies, <em>Bispathodus</em>-<em>Pseudopolygnathus</em> and <em>Gnathodus</em> subbiofacies, are identified. Changes in these conodont biofacies and subbiofacies are interpreted as a result of fluctuation of sea level in the Baoshan Block during the middle to late Tournaisian, Early Mississippian. <em>Geniculatus claviger</em> is recovered and systematically described in China for the first time.</p></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"33 3","pages":"Pages 636-649"},"PeriodicalIF":1.7,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"55105961","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":"Carbon and conodont apatite oxygen isotope records from the Alengchu section in western Yunnan and their paleoclimatic and paleogeographic implications","authors":"Bo Chen ,&nbsp;Mei-Qiong Zhang ,&nbsp;Wen-Kun Qie ,&nbsp;Kun Liang ,&nbsp;Jian-Feng Lu ,&nbsp;Michael M. Joachimski ,&nbsp;Xue-Ping Ma","doi":"10.1016/j.palwor.2022.12.010","DOIUrl":"10.1016/j.palwor.2022.12.010","url":null,"abstract":"<div><p>The Early Devonian witnessed dramatic changes in climate, ocean chemistry and faunal evolution. However, previous studies have relied mainly on records from North America and Europe (Prague Basin, Carnic Alps) and Australia, while data from China have been rarely reported, hindering robust δ¹³C_carb chemostratigraphic correlation and evidence for the global significance of these events. Here, we report new carbon isotope and conodont apatite oxygen isotope records from the Alengchu section in western Yunnan which represents the most continuous Lower Devonian carbonate succession in China. Our study reports two positive δ¹³C_carb excursions (Klonk isotope event, Lochkovian–Pragian isotope event) that can be correlated with published records globally. However, δ¹⁸O_apatite values are higher compared to coeval data from other sections. These higher values are interpreted as indicating cooler surface water temperatures as consequence of a persistent upwelling system at low latitudes which is consistent with the paleooceanographic circulation pattern reconstructed from combined evidence of climate modelling and geographic distribution of marine benthic ostracod assemblages.</p></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"33 3","pages":"Pages 559-569"},"PeriodicalIF":1.7,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42393328","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":"First record of the late Famennian conodonts in Qamdo, Tibet and their biostratigraphic implications","authors":"Yu-Ze Huang ,&nbsp;Wen Guo ,&nbsp;Wei Lin ,&nbsp;Ping-Cuo Zhaxi ,&nbsp;Le Yao ,&nbsp;Ke-Yi Hu ,&nbsp;Qiu-Lai Wang ,&nbsp;Yu-Ping Qi","doi":"10.1016/j.palwor.2023.09.001","DOIUrl":"10.1016/j.palwor.2023.09.001","url":null,"abstract":"<div><p>Based on the conodonts recovered for the first time and some brachiopods, this study revises the age of the Wuqingna Formation in eastern Tibet to a late Famennian, challenging prior Carboniferous classification based on coral assemblages. In this study, conodonts are described for the first time from the Wuqingna Formation on the Wuqingka Mountain near Toba Town, Qamdo City in eastern Tibet. The conodont assemblage contains 6 species/subspecies (including morphotypes within open nomenclature) that belong to three genera. The conodont species <em>Polygnathus</em> cf. <em>perplexus</em>, <em>Po</em>. <em>homoirregularis</em>, <em>Po</em>. <em>wuqingnaensis</em> n. sp. and <em>Scaphignathus peterseni</em> suggest an age of late Famennian, probably the <em>Palmatolepis gracilis manca</em> Zone to the <em>Pa</em>. <em>gr</em>. <em>expansa</em> Zone, for the lower part of the Wuqingna Formation, which was previously assigned to the Carboniferous based on the rugose coral assemblages.</p></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"33 3","pages":"Pages 624-635"},"PeriodicalIF":1.7,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135249360","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":"Ordovician conodonts from the Ban Tha Kradan area, western Thailand","authors":"Zhong-Yang Chen ,&nbsp;Wen-Jie Li ,&nbsp;Xiang Fang ,&nbsp;Chao Li ,&nbsp;Clive Burrett ,&nbsp;Mongkol Udchachon ,&nbsp;Yuan-Dong Zhang","doi":"10.1016/j.palwor.2022.12.004","DOIUrl":"10.1016/j.palwor.2022.12.004","url":null,"abstract":"<div><p>Eleven Ordovician conodont species of nine genera from the Ban Tha Kradan area of western Thailand are described and illustrated here for the first time. Based on similar lithological features and stratigraphical range, the upper part of Tha Manao Formation in the Ban Tha Kradan area of Kanchanaburi Province is amended and assigned to the Pa Kae Formation. The <em>Scolopodus striatus</em> Assemblage Zone is recognized in the revised Tha Manao Formation in the Ban Tha Kradan area. Based on conodonts and macrofossils, the Tha Manao Formation in western Thailand is assigned to the upper Floian to Darriwilian, and the conformably overlying Pa Kae Formation to the Sandbian to lower Katian.</p></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"33 3","pages":"Pages 546-558"},"PeriodicalIF":1.7,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47934578","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":"Middle Devonian (Givetian) coral-stromatoporoid patch reefs from the Lazhuglung Formation, Xizang (Tibet) and their palaeoecological and palaeogeographical implications","authors":"Kun Liang ,&nbsp;Yi-Chun Zhang ,&nbsp;Ji-Tao Chen ,&nbsp;Mao Luo ,&nbsp;Wen Guo ,&nbsp;Wen-Kun Qie","doi":"10.1016/j.palwor.2023.02.005","DOIUrl":"10.1016/j.palwor.2023.02.005","url":null,"abstract":"<div><p>We carried out, for the first time, detailed studies on the coral-stromatoporoid patch reefs from the Lazhuglung Formation near Shouxinghu in the Lazhuglung-Badangco area, Ngari Prefecture of Xizang (Tibet) Autonomous Region, China. On the basis of 1085 thin sections prepared from three patch reefs, the fossil components and reef structures are depicted. The patch reefs are found to encompass diverse fossil organisms, including tabulate and rugose corals, stromatoporoids, brachiopods, gastropods, ostracods, nautiloids, calcified cyanobacteria, and tubeworms. Tabulate corals and stromatoporoids are the predominant reef-builder, particularly <em>Alveolites obtortus</em> and <em>Gerronostromaria gromotuchense</em>. The patch reefs are Middle Devonian Givetian in age based on the tabulate coral and stromatoporoid assemblage. Extensive biotic interactions between the reef organisms are found in all three patch reefs, which are beneficial for the reef formation and development. The ecological features of the corals and stromatoporoids indicate a mesophotic ecosystem that is widespread in the Givetian. In addition, the common species and similar characteristics between the faunas in the Lazhuglung Formation, North Qiangtang Block and those in South China suggest a close palaeobiogeographic relationship. This study enhances our understanding on fossil components, reef structure and tectonic affiliation of the Palaeozoic strata in the Lazhuglung-Badangcuo area.</p></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"33 3","pages":"Pages 612-623"},"PeriodicalIF":1.7,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45115858","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":"Sedimentary processes of the Lower Permian Dingjiazhai Formation in the Baoshan Block","authors":"Biao Gao ,&nbsp;Ji-Tao Chen ,&nbsp;Wen-Li Yang ,&nbsp;Hao Xin ,&nbsp;Xiang-Dong Wang","doi":"10.1016/j.palwor.2023.09.005","DOIUrl":"10.1016/j.palwor.2023.09.005","url":null,"abstract":"<div><p><span><span>The Baoshan Block was part of the eastern Cimmerian continent along the northeastern margin of Gondwana<span><span> during the late Paleozoic, and preserves continuous sedimentary records during the apex of the Early Permian glaciation. Although much work has been carried out on </span>biostratigraphy and </span></span>paleogeography, detailed sedimentological study of the glacial records in the Baoshan Block has gained little attention, which hampers the understanding of </span>depositional processes<span> along the northeastern margin of Gondwana. Here, we conduct a high-resolution sedimentological study on the Lower Permian Dingjiazhai Formation of the Baoshan Block, with the aim of reconstructing the evolution of sedimentary environments<span><span>. Six major lithological facies and three facies associations are recognized from the Dongshanpo section. The diamictite<span><span> facies association is composed of weakly stratified diamictite, stratified diamictite, and massive sandy siltstone facies, which are formed by proglacial outwash debris flows and settling of melt-water plumes. The lenticular gravelly sandstone facies association consists of lenticular gravelly sandstone, thin-bedded siltstone, and homogenous silty </span>mudstone facies, suggesting a distal subaqueous proglacial offshore setting with episodic </span></span>melt water<span> plumes. The bioclastic rudstone facies association comprises of bioclastic rudstone and floatstone, and thin-bedded siltstone facies, which suggest an offshore depositional environment<span> punctuated by bioclastic gravity flows. Accordingly, we reconstructed a gradually changed sedimentary model responding to the Early Permian deglaciation in the Baoshan Block, which probably represents a typical evolution of sedimentary environments along the northeastern margin of Gondwana during the Early Permian.</span></span></span></span></p></div>","PeriodicalId":48708,"journal":{"name":"Palaeoworld","volume":"33 3","pages":"Pages 664-678"},"PeriodicalIF":1.7,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134995331","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}