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Reinvestigation of Devonian-Carboniferous palynostratigraphy in Yalai village, Nyalam County, southern Tibet, China
Abstract
Reinvestigation of the Devonian-Carboniferous boundary sequence in Yalai village, Nyalam County, southern Tibet, enabled the recovery of well-preserved palynomorphs and conodonts in the Yali section. Based on quantitative analysis of the relative abundances of various palynomorphs, two palynological assemblages are recognized in the Famennian-Tournaisian boundary beds of the Yali section. In ascending order, they are the Retispora lepidophyta–Verrucosisporites irregularis (LI) assemblage and the Retispora lepidophyta–Vallatisporites vallatus (LV) assemblage. Both assemblages are tentatively correlated with the Famennian LN Biozone of Western Europe because of the appearance of Retispora lepidophyta and other index spores such as Vallatisporites verrucosus, Vallatisporites pusillites, Indotriradites explanatus, and Densosporites spitsbergensis in both palynological assemblages. The lower limestones of the Yali Formation yield biostratigraphic markers for the Devonian-Carboniferous boundary, including the conodont Siphonodella sulcata and Protognathodus kockeli, correlated with the VI Biozone from Western Europe and parts of Gondwana. The upper Lazhabu Member of the Yali Formation yielded Retispora lepidophyta, Vallatisporites vallatus, and Vallatisporites pusillites of the LV Biozone, indicating that some typical palynomorphs elements of the LN Biozone of Western Europe persisted into Tournaisian in southern Tibet.
... sulcata zones. The underlying Zhangdong Formation is composed of black and gray-green shale with minor siltstone containing abundant miospores, and the Retispora lepidophyta-Verrucosisporites irregularis (LI) and R. lepidophyta-Vallatisporites vallatus (LV) assemblages were identified by Peng et al. (2022), corresponding to the LN Assemblage. ...
... praesulcata, Si. sulcata, Si. duplicata, Si. isosticha and Gnathodus pseudosemiglaber zones and suggested that the D-C boundary should be located in the Goulongri Member of the Yali Formation, marked by the first occurrence of Si. sulcata. More recent research has shown that the first occurrence of the conodont Pr. kockeli is located 4.3 meters above the base of the Yali Formation, while the conodont Si. sulcata already appears at the top of the Yalidonggou Member of the Yali Formation, suggesting that the D-C boundary in this area should be moved downwards (Peng et al., 2022). ...
... The Yali Formation is composed of gray, medium-thin to medium-thick-bedded lime mudstones, bioclastic limestones and argillaceous limestones, with more calcareous mudstone in the upper section. The Yali Formation contains diverse fossils, including ammonoids, conodonts and brachiopods, representing a lithostratigraphic unit that spans the Devonian-Carboniferous boundary (Qiu and Lin, 1984;Peng et al., 2022). In the Spiti Valley of India and the Kashmir Region, the Devonian mainly includes the Muth, Lipak and Wazura formations, which are characterized by shallowwater mixed continental shelf facies. ...
... Several number of palynological studies have been carried out from Devonian-Carboniferous strata of the world and is continuously being updated for high-resolution palynostratigraphy and correlation of contemporary strata across the globe, especially from South America (Brazil: Loboziak et al., 2000;Melo & Loboziak, 2003;Muro et al., 2020;Playford et al., 2012;Souza et al., 2003Souza et al., , 2015 and references therein), Argentina (Césari & Perez Loinaze, 2021;Gutiérrez & Balarino, 2018;Loinaze, 2005;Loinaze et al., 2014;Noetinger & Di Pasquo, 2011;Pineda et al., 2021;Rubinstein et al., 2017; and references therein), South Africa (Streel & Theron, 1999), Europe (Avchimovitch, 1992;Avchimovitch et al., 1988Avchimovitch et al., , 1993Clayton et al., 1977Clayton et al., , 1978Filipiak, 2004;Higgs et al., 2000;Maziane et al., 1999;Streel et al., 1987; and references therein), Australia (Playford & Satterthwait, 1986), Turkey (Higgs et al., 2002) and China Liu et al., 2019;Peng et al., 2022;Wellman et al., 2012;Xu et al., 2022;and references therein). ...
The present work elucidates palynofloral records from the Lipak Formation (late Devonian– early Carboniferous) of the Spiti Basin. The study has been carried out from three different sections of Spiti and Pin valleys to look for the signatures of terrestrial plants in the Tethyan realm and assess the relative palynodating of the studied sediments. The recovered palynoassemblage from the exposures of Lipak Formation, near Takche Locality, Spiti Valley, mainly comprises spores and has the dominance of Verrucosisporites, Dictyotriletes, Lophozonotriletes, Convolutispora followed by subordinate occurrences of Rugospora, Cymbosporites and Knoxisporites along with reworked pollen grain Plicatipollenites. The recovered palynoassemblage of Lipak Formation exposure at Guling Village of Pin Valley comprises Spelaeotriletes, Tricidarisporites, Calamospora, Callumispora and reworked pollen grains. The reworked pollen grains are characterised by the dominance of Faunipollenites, Scheuringipollenites and Parasaccites and followed by subordinate occurrences of the Densipollenites, Striatopodocarpites, Platysaccus, Alisporites, Striomonosaccites, Chordasporites and Verticipollenites pollen grains. The exposure of this Formation near Muth Village of Pin Valley is found to be palynologically barren. The recovered palynoflora is correlated with palynofloral records of the Tethyan realm of India and palynofloral records from coeval sequences worldwide. The recovered palynocomposition shows a close resemblance to Retispora lepidophyta–Verrucosisporites nitidus (LN) and Vallatisporites verrucosus–Retusotriletes incohatus (VI) Assemblage zones of Western Europe and Cordylosporites–Verrucosisporites Biozone of Argentina which indicates that studied section of the Lipak Formation is upper Famennian to early Tournaisian age. The recovered reworked palynomorphs belong to the Permian age, which may be deposited in the Lipak Formation through stratigraphic leakage. Palynomorphs include spores of affinities of Zygopteridiales, Marattiales, Botryopteridales, Equisetales/Noeggerathiales/Sphenophyllales group of plants. In contrast, palaeobotanical affinities of pollen grains are linked with the Filicales, Cordaitales and Glossopteridales group of plants.
... Recently, Liu et al. (2019) and Peng et al. (2022) also restudied the miospores from the same section, contributing to a better understanding of the conodont-miospore correlation. Furthermore, Qiu (1984) reported conodonts such as G. girtyi collinsoni and G. girtyi simplex from the Visean strata in the Xainza area. ...
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 Polygnathus cf. perplexus, Po. homoirregularis, Po. wuqingnaensis n. sp. and Scaphignathus peterseni suggest an age of late Famennian, probably the Palmatolepis gracilis manca Zone to the Pa. gr. expansa Zone, for the lower part of the Wuqingna
Formation, which was previously assigned to the Carboniferous based on the rugose coral assemblages.
The Devonian System in the Qinghai-Tibetan Plateau and its surrounding areas is widely distributed, diverse in lithotypes and rich in fossils. It records the crucial processes of continuous subduction and reduction of the Paleo-Asian Ocean in the northern hemisphere and the transformation of the Proto-Tethys Ocean into the Paleo-Tethys Ocean in the southern hemisphere. Thus, it is of great significance for explaining the global paleogeographic evolution, tectonic activities and biodiversity changes during this critical period. The blocks on both sides of the southern Tienshan suture zone and the Longmu Co-Shuanghu-Changning-Menglian suture zone belong to different sedimentary systems and paleobiogeographic realms and regions, showing important tectonic paleogeographic partitioning significance. The two suture zones represent the main branches of the Paleo-Asian Ocean and the Paleo-Tethys Ocean, respectively, and on this basis the Devonian System can be subdivided into three types: the Tienshan type, the Tethys type and the Gondwana type. Based on recent research progress on the Devonian stratigraphy and paleontology in combining provenance analysis and biotic characteristics in the Qinghai-Tibetan Plateau and surrounding areas, this paper aims to establish the latest integrative stratigraphic framework and conduct paleogeographic reconstruction, providing foundation for exploring the geological evolution and dynamic mechanisms of various terranes and blocks in the northern margin of Gondwana. The results indicate that the North Qiangtang, South Qiangtang, Simao, Baoshan and Tengchong terranes, as well as the Himalaya Tethys Zone and the South China Block have affinities with the Indian Block, while the Lhasa Terrane has affinities with the Australian Block, and may be located between the South China and Australian blocks. In the Emsian (Early Devonian), the South China Block separated from the northern margin of Gondwana, a process that was accompanied by the opening of the Jinshajiang-Ailaoshan Ocean. In the Middle Devonian, the mid-oceanic ridge of the Paleo-Tethys Ocean expanded rapidly, corresponding with a global sea-level rise, the widespread development of carbonate platforms and nadir values of Devonian seawater strontium isotopes. By the Late Devonian, the Paleo-Tethys Ocean had reached a considerable size, leading to abundant occurrences of Upper Devonian radiolarian cherts in the Paleo-Tethys suture zones.
During the Carboniferous Period, the Qinghai-Tibetan Plateau and its surrounding areas were located in quite different paleogeographic positions with various sedimentary and biological types. It is important to systematically compile and summarize the Carboniferous strata and biotas of the Qinghai-Tibetan Plateau and its surrounding areas, to establish an integrated stratigraphic framework for correlation, and to reconstruct the paleogeography for correctly understanding the breakup of the Gondwana Continent and the evolution of the Paleo-Tethys Ocean in the Late Paleozoic. The Carboniferous of the Qinghai-Tibetan Plateau and its surrounding areas can be subdivided into the Gondwanan, Cimmerian, and Tethyan types. The Gondwanan-type Carboniferous are distributed in the North Himalayan, Kangmar-Lhunze, and Zanda-Zumba regions of the South Tibet Subprovince and northern India-Pakistan Area, where only the Mississippian is developed and the biota is of Gondwanan affinity. The Cimmerian-type Carboniferous, which are found in the Baoshan, Tengchong, Coqen-Xainza, Lhasa-Zayu, Nagqu-Biru, and South Qiangtang regions, as well as Shan-Thai and South Afghanistan-Pamir areas, also represent only the Mississippian strata, but their biota is characterized by mixed characters of European, South China, Australian, and North American types. The Tethyan-type Carboniferous are distributed in the Tanggula Mountains, Hoh Xil-Bayanhar, Chamdo-Hengduanshan, Tiekelike, West Kunlun, Karakorum, East Kunlun-Central Qinling, and Qilian regions, where the Carboniferous succession is well developed, and the biota is of warm-water Tethyan affinity. The biostratigraphical correlation of the Gond-wanan-type and Cimmerian-type Carboniferous is based mainly on conodonts and additionally on brachiopods and rugose corals. The Mississippian of the Tethyan-type Carboniferous is correlated mainly by using rugose corals and brachiopods, whereas in the Pennsylvanian foraminifera (fusuline) and conodonts are regarded as primary fossil groups, subordinated by rugose corals and brachiopods. Adhering to the International standard chronostratigraphy of the Carboniferous, we have reconstructed a framework of the litho- and biostratigraphic subdivision and correlation of the Qinghai-Tibetan Plateau and its surrounding areas. Further studies should focus on isotope geochronology, geochemistry, paleoclimates, and paleoenvironments of the Carboniferous in the Qinghai-Tibetan Plateau and its surrounding areas.
The Borkewehr section near Balve at the southeastern end of the Remscheid-Altena Anticline is currently the best and most complete Devonian/Carboniferous Boundary (DCB) succession of the Rhenish Massif, Germany. Based on a multidisciplinary approach, focusing on refined conodont and ammonoid biostratigraphy, microfacies analyses, sequence stratigraphy, carbon isotopes (C org and C carb ), trace element geochemistry, including REE data, and cyclostratigraphy, the section is proposed as a candidate for the new basal Carboniferous GSSP. The succession represents a pelagic “seamount” setting. It spans the upper Famennian to lower Viséan, with a condensed development of most Rhenish lithostratigraphic units and sedimentary sequences. It is the type-section of the oxic and strongly cyclic, fossiliferous Wocklum Limestone and of important uppermost Famennian and basal Carboniferous index species. The First Appearance Datum (FAD) of Protognathodus kockeli s.str., in a phylogenetic succession from the ancestral Pr. semikockeli n. sp., is proposed as future GSSP level. This FAD is sandwiched between many other marker levels for global correlation. Below are, from base to top, the transgressive base of the at least partly anoxic Hangenberg Black Shale (base Lower Hangenberg Crisis Interval), the Hangenberg Regression (onset of siltstones of the basal Middle Crisis Interval), the level of maximum regression, indicated by maximum Zr/Al values, and the initial transgression of the basal Upper Crisis Interval, marked by the re-onset of carbonate deposition. Above follow the locally cryptogenic FAD of Siphonodella (Eosiphonodella) sulcata s.l. at the base of the post-Crisis Interval (Hangenberg Limestone), associated with a conodont biofacies shift, the FAD of Si. (Eo.) bransoni , and, much higher, the sharp Lower Alum Shale Event at the base of the classical middle Tournaisian. The significance of the section is greatly enlarged by its precise correlation with numerous other Rhenish DCB sections that provide important additional data on faunas, geochemistry, geochronological ages, and magnetic susceptibility. The new Borkewehr data suggest changes of weathering intensity, based on Rb/K and K/Al trends, and Milankovitch cyclicity associated with the climate changes of the Hangenberg Crisis. The local conodont extinction rate at the top of the Wocklum Limestone lies at 57 % while there are no survivors in ammonoids, trilobites, or deep-water corals. Positive carbon isotopic shifts of carbonate in the Upper Crisis Interval and of C org in the Middle Crisis Interval are decoupled, which suggests complex underlying processes that are not yet understood.
Thirty Devonian-Carboniferous Boundary sections of the Rhenish Slate Mountains and adjacent subsurface areas are reviewed with respect to litho-, event, conodont, ammonoid, sequence, and chemostratigraphy. In the interval from the base of the uppermost Famennian (Wocklum Beds, Wocklumian) to the base of the middle Tournaisian (base Lower Alum Shale), 11 conodont and 16 ammonoid (sub)zones are distinguished. The terminology of the Hangenberg Crisis Interval is refined, with an overall regressive Crisis Prelude below the main Hangenberg Extinction, which defines the base of the transgressive Lower Crisis Interval (Hangenberg Black Shale). The glacigenic and regressive Middle Crisis Interval (Hangenberg Shale/Sandstone) is followed by the overall transgressive Upper Crisis Interval that can be subdivided into three parts (I to III) with the help of conodont stratigraphy (upper costatus-kockeli Interregnum = upper ck I, Protognathodus kockeli Zone, and lower part of Siphonodella ( Eosiphonodella ) sulcata s.l./ Pr. kuehni Zone). Protognathodus kockeli includes currently a wide range of forms, which variabilities and precise ranges need to be established before a precise GSSP level should be selected. Returning to its original definition, the former Upper duplicata Zone is re-named as Siphonodella ( S. ) mehli Zone. It replaces the S. ( S. ) jii Zone, which is hampered by taxonomic complications. The S. ( S. ) quadruplicata Zone of Ji (1985) is hardly supported by Rhenish data. The entry of typical S. ( S. ) lobata (M1) characterises an upper subdivision (subzone) of the S. ( S. ) sandbergi Zone; the new S. ( S. ) lobata M2 enters much earlier within the S. ( S .) mehli Zone. The ammonoid-defined base of the Wocklum-Stufe (Upper Devonian = UD VI) begins with the Linguaclymenia similis Zone (UD VI-A 1 ). The oldest S. ( Eosiphonodella ) enter within the Muessenbiaergia bisulcata Zone (UD VI-A 2 ). The traditional Parawocklumeria paradoxa Zone of Schindewolf (1937) is divided into successive P. paprothae (VI-C 1 ), P. paradoxa (VI-C 2 ), and Mayneoceras nucleus (VI-C 3 ) Subzones. In the lower Tournaisian (Lower Carboniferous = LC I), the Gattendorfia subinvoluta Zone is subdivided into G. subinvoluta (LC I-A 2 ) and “ Eocanites ” nodosus (LC I-A 3 ) Subzones. The Paprothites dorsoplanus Zone (LC I-B) can be divided into Pap. dorsoplanus (LC I-B 1 ) and Paragattendorfia sphaeroides (LC I-B 2 ) Subzones. Potential subdivisions of the Pseudarietites westfalicus (LC I-C) and Parag. patens Zones (LC I-D) are less distinctive. The unfossiliferous or argillaceous upper part of the Hangenberg Limestone and the overlying Lower Alum Shale Event Interval remain regionally unzoned for ammonoids.
There is an unexplained terrestrial mass extinction at the Devonian-Carboniferous boundary (359 million years ago). The discovery in east Greenland of malformed land plant spores demonstrates that the extinction was coincident with elevated UV-B radiation demonstrating ozone layer reduction. Mercury data through the extinction level prove that, unlike other mass extinctions, there were no planetary scale volcanic eruptions. Importantly, the Devonian-Carboniferous boundary terrestrial mass extinction was coincident with a major climatic warming that ended the intense final glacial cycle of the latest Devonian ice age. A mechanism for ozone layer reduction during rapid warming is increased convective transport of ClO. Hence, ozone loss during rapid warming is an inherent Earth system process with the unavoidable conclusion that we should be alert for such an eventuality in the future warming world.
Recent refinements of the palynological stratigraphic scheme around the Devonian-Carboniferous Boundary in southern Belgium result in new questions on the effect of the Hangenberg Biocrisis on spores and on the validity of some ‘biozones’. Verrucosisporites nitidus, the guide taxa of the last Devonian palynozone (LN zone) is lacking in many sections and its presence is only acknowledged in proximal settings. Hence the LN zone is considered as an ecozone rather than a biozone. Moreover, investigation of the uppermost part of the uppermost Famennian shows that the palynological assemblages is dominated by abnormal forms of Retispora lepidophyta, notably by R. lepidophyta var. tener which seems to be characteristic of this interval in Western Europe. It is thus proposed to introduce the global tener event as a potential marker of the Hangenberg Biocrisis on land and in proximal marine settings. This profusion of abnormal spores is thought to be related to climatic variation possibly in link with global cooling below the Devonian-Carboniferous Boundary.
The Middle Member of the Zorritas Formation in the Antofagasta Region of northern Chile, yielded terrestrial and marine palynomorph assemblages which span the Devonian/Carboniferous boundary. The assemblages show a clear predominance of terrestrial palynomorphs with 70 miospore species, 18 marine phytoplankton species, two non-marine algae and one chitinozoan species, all coming from 15 productive levels. Palynomorphs are poorly preserved and most of them are reworked. Three palyno-logical associations are recognized based on miospores. These are assigned to the TournaisianeVisean, Tournaisian and probable latest Famennian. Age assignments are discussed in the frame of the spore zonal schemes established for Euramerica and western Gondwana. The stratigraphical distribution of spores allows the identification of the probable position of the Devonian/Carboniferous boundary within the Zorritas Formation. This system boundary is proposed for the first time in Palaeozoic sedimentary rocks of northern Chile. The presence of Gondwanan typical miospore species indicates affinities with this palaeocontinent even though the Tournaisian and TournaisianeVisean miospore associations support the cosmopolitanism already suggested for the early Carboniferous flora. The significant number of reworked palynomorphs together with the sedimentological analysis of the studied sections, suggest that these deposits were severely impacted by the climatic change and major sea level fluctuations. Similar conditions were recorded in coeval western Gondwana basins. Ó 2016, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).
The Middle Member of the Zorritas Formation in the Antofagasta Region of northern Chile, yielded terrestrial and marine palynomorph assemblages which span the Devonian/Carboniferous boundary. The assemblages show a clear predominance of terrestrial palynomorphs with 70 miospore species, 18 marine phytoplankton species, two non-marine algae and one chitinozoan species, all coming from 15 productive levels. Palynomorphs are poorly preserved and most of them are reworked. Three palynological associations are recognized based on miospores. These are assigned to the Tournaisian–Visean, Tournaisian and probable latest Famennian. Age assignments are discussed in the frame of the spore zonal schemes established for Euramerica and western Gondwana.
Two new sections displaying the Devonian-Carboniferous Boundary beds at Stockum and in the Hasselbachtal borehole have been palynologically investigated. Twenty eight productive samples have been obtained and the miospore assemblages are assigned to the LN and VI Miospore biozones. The LN/VI Biozonal boundary is accurately located with the uppermost 45 cm of the Hangenberg Shales in both sections. The correlation of the miospore data with the goniatite and conodont faunas is discussed. -from Authors
Diverse and well-preserved latest Permian phytoplankton assemblages are described from four sections of the Yangtze Block, South China from localities in Zhongzhai (Guizhou Province), Shangsi (Sichuan Province), Xiakou (Hubei Province) and Dongpan (Guangxi Province). Most of the species have been reported previously from other upper Permian sections worldwide. The South Chinese phytoplankton taxa are generally very small in size, usually displaying diameters of about 20 μm and commonly include the genera Micrhystridium, Veryhachium and Leiosphaeridia. However, larger taxa with vesicles often exceeding 80 μm in diameter, such as Dictyotidium, are also abundant in the Shangsi section. Due to the presence of large populations of Micrhystridium and Veryhachium, a simple classification scheme for the Micrhystridium/Veryhachium complex is proposed, based on the geometrical shape of the vesicle. We propose dividing the complex into five groups: the Veryhachium cylindricum group, representing all ellipsoidal specimens; the Veryhachium trispinosum group, all with triangular-shaped vesicles; the Veryhachium lairdii group, all with rectangular forms; the Micrhystridium pentagonale group, all with pentagonal specimens; and the Micrhystridium breve group, which includes all spherical forms.
A miospore zonal scheme for late Early - Late Devonian strata of Western Gondwana is presented. Itis based on the first occurrences of both distinctive zonal taxa or groups of taxa of the most significative biozonations of Southern Euramerica and endemic Western Gondwanan species.
This paper concerns the description of palynomorphs recovered from subsurface Early Carbonifer- ous strata of the SM-4 well located in the Llanos Orientales Basin, Colombia. Thirty-two species of spores are recognized within the palynoflora. A new species is proposed: Spelaeotriletes colombianus Dueñas and Césari sp. nov. The assemblages were referred to the Tournaisian-Viséan by the presence of distinctive spore species with previous records in the Viséan and Tournaisian of Western Europe and Western Gondwana.
Pteridophytic spores recovered from the Takoradi Shale Formation at Essipon Beach near Sekondi in western Ghana are abundant and diverse. They are mainly trilete spores, both laevigate and sculp-tured. In all, 36 species are described and illustrated. The spores and the alga Tasmanites indicate a freshwater swamp or marsh environment of deposition. Organic-walled microplankton (acritarchs) associated with the spores imply marine or brackish incursions. Stratigraphically significant spore taxa indicate a latest Devonian (Strunian Tn 1a)–Early Carboniferous (Tournaisian Tn 1b) age for the sediments by comparison with similar taxa reported especially from western Europe, the former USSR and North America. Resumen Se describe la presencia abundante y diversa de esporas de pteridofitas en la Formación Takoradi Shale, en Essipon Beach, en las cercanías de Sekondi, oeste de Ghana. Principalmente son esporas de tipo triletes, lisas y ornamentadas. Se describen e ilustran 36 especies. Las esporas y los restos del alga Tasmanites indican la existencia de un medio de deposición de tipo pantano o marisma. La pre-sencia de microplancton de paredes orgánicas (acritarcos) asociado con las esporas indica la exis-tencia de incursiones marinas o salobres. La presencia de determinados taxones de esporas significa-tivas desde el punto de vista estratigráfico indica una edad Devónico Superior (Struniense Tn 1a)–Carbonífero Inferior (Tournaisiense Tn 1b) cuando se comparan con asociaciones similares des-critas en Europa occidental, en la antigua URSS y Norteamérica.
A spore zonation scheme comprising fifty-one zones is proposed for the marine Devonian strata of the Ardenne-Rhenish regions of Western Europe. The zonation comprises a series of Oppel and interval-type zones and these are closely intercalibrated with the associated marine faunal zonations to give a seventy-five level scale of correlation for the Devonian succession. The spore zonation provides stratigraphical dating of the Devonian megafloras of the region, particularly those from the Lower and Middle Devonian. The proposed spore zonation is closely compared with that erected for the Devonian of the Old Red Sandstone Continent.
A miospore biozonation, including 17 new interval zones, is proposed for Devonian–Early Carboniferous stratigraphic sections in the Amazon Basin. It results from a detailed review of the coeval miospore assemblages and biohorizons in the basin. The combined use of selected Euramerican and Western Gondwanan forms as zonal and characteristic taxa permits accurate subdivision, dating and correlation of Amazon Basin palyniferous strata in terms of equivalent miospore zones of Western Europe and the Old Red Sandstone Continent. The miospore data provide new insights into such varied issues as e.g. the age and stratigraphic relationships of regional rock units, the detection and dating of intervening hiatuses, condensed sedimentary sections, anoxic phases, and resedimentation cycles. Although primarily devised to serve as a regional biozonation, the scheme presented here has a unifying character because it can be applied to other Paleozoic basins in Brazil and Western Gondwanan regions where similar miospore successions are documented. A miospore assemblage zone recently described for the early Late Carboniferous interval of the Amazon Basin is also partly reviewed and integrated with the new biozonation for the older sections.
Stratigraphically constrained cluster analysis is a multivariate method for quantitative definition of stratigraphic zones. As opposed to ordinary, unconstrained cluster analysis, only stratigraphically adjacent clusters are considered for merging. The method of incremental sum of squares has been used widely for unconstrained analyses and has proved particularly satisfactory for pollen frequency data. CONISS is a FORTRAN 77 program for stratigraphically constrained cluster analysis by this method. Several data transformations lead to different implicit dissimilarity coefficients. As an option, the program also will perform an unconstrained analysis, which can be useful for comparison with the constrained analysis.
Late Devonian–Early Carboniferous spores recovered from the depths of 2140 m to 2031.3 m in the CSDP-2 Borehole in the southern Yellow Sea are systematically documented to characterize palynological associations for the stratigraphic correlation. The taxonomic study identifies 96 species belonging to 48 genera, including a re-examination of 33 previously described and indeterminate species. Three palynological associations are established for the Wutong Formation in the CSDP-2 Borehole. In ascending order, these are the late Famennian Aneurospora asthenolabrata–Geminospora lemurata (AL) Association from the proposed Guanshan Member, the latest Famennian Cymbosporites circinatus–Asperispora acuta (CA) Association from the lower part of the proposed Leigutai Member, and the Tournaisian Auroraspora macra–Lophozonotriletes involutus (MI) Association of the upper part of the latter member. The AL and CA associations are correlated with the palynological assemblages in the Guanshan Member, and those in the lower to middle parts of the Leigutai Member of the Wutong Formation that outcrops in the suburbs of Nanjing and southern Jiangsu. The MI Association is similar to those derived from the uppermost beds of the subsurface Wutong Formation and is dated as early Tournaisian.
The end-Permian mass extinction (EPME) is regarded as the most severe biotic crisis in Earth history, which is particularly well-documented in the marine fossil record. Despite compelling evidence that dramatic global environmental changes probably drove this extinction event, its effects on terrestrial plants are still highly controversial. Here we present Changhsingian (latest Permian) to late Smithian (latest Early Triassic) composite palynological successions from the lagoonal to open marine Qubu and Tulong sections in southern Tibet. Quantitative analyses of palynomorph distributions (range charts and relative abundance data) allow us to differentiate five distinct, informal palynofloral assemblages in ascending order: the Scheuringipollenites ovatus–Vitreisporites pallidus (OP) assemblages, the Reduviasporonites catenulatus (С) assemblage, the Endosporites papillatus–Pinuspollenites thoracatus (PT) assemblages, the Lundbladispora brevicula–Densoisporites nejburgii (BN) assemblages and the Falcisporites nuthallensis–Alisporites landianus (NL) assemblages. These palynological assemblage intervals and the associated ammonoid and conodont biostratigraphy resolve vegetation changes across the Permian–Triassic boundary (PTB) on the northern Tethyan margin of Gondwanaland in great detail and high resolution. Principal Component Analysis (PCA) of palynological data indicates that the OP assemblages, which are dominated by non-taeniate bisaccate pollen, represent a vegetation in a cool and dry climate during the Changhsingian. In the Qubu Section, the palynological turnover from the OP assemblages to the C assemblage 0.81 m below the PTB, coincides with abrupt sea-level fluctuations in the latest Permian. As this turnover further coincides with an extreme negative δ¹³Corg shift, a great abundance of amorphous organic matter (AOM) and marine acritarchs as well as the frequent occurrence of Reduviasporonites catenulatus, the C assemblage is tentatively interpreted to represent the “fungal spike” reported worldwide at the onset of the EPME. In southern Tibet, the EPME appears to result only in a short-term disturbance and range contraction of land-plant communities. Surprisingly, the early Dienerian PT assemblages, postdating the EPME by about 500Kyrs, closely resemble the late Changhsingian OP assemblages, suggesting a resurgence of those land plant groups that were dominant during the late Changhsingian. This recovery was disrupted with the onset of the late Dienerian BN assemblages in the Qubu Section, which is represented by a peak abundance of cavate trilete spores, reflecting large-scale deforestation. For nearly one million years, the regional vegetation appears to have been dominated by pioneer communities of quillworts and spike mosses. Only towards the end of the Smithian, bisaccate gymnosperm pollen regained dominance with the onset of the NL assemblages in the Tulong Section. Integrating the results of the Principal Component Analysis on our new palynological data and conodont-apatite oxygen-isotope data from neighbouring sections in Pakistan, the contraction of gymnosperm forests during the early Dienerian–Smithian in southern Tibet is interpreted to be accompanied by an abrupt change to an episode with a warmer and more humid climate.
This observation supports the hypothesis that the secondary eruptions of the Siberian Large Igneous Province during the Induan led to long-term global warming and, as a side effect, to more humid conditions in the southern temperate zone as a result of altered precipitation and evaporation patterns.
Palynological assemblages from the Tulong succession in South Tibet enabled the recognition of three miospore biozones within the Zhangdong and ‘Yali’ formations. In ascending order, they are the Retispora lepidophyta–Verrucosisporites nitidus (LN) Biozone, the Vallatisporites vallatus–Foveosporites pellucidus (VP) Biozone and the Rugospora polyptycha–Tricidarisporites arcuatus (PA) Biozone. The LN Biozone in the Tulong section can be correlated to the LN Biozone of Western Europe, based on the first and last appearances of many index miospore species. However, Tournaisian palynological assemblages of Western Europe and South Tibet show compositional differences. The VP and PA biozones of South Tibet are correlated tentatively to the VI–HD and BP–TC biozones of Western Europe based on the occurrences of rare miospore index species in both regions. The Zhangdong and ‘Yali’ formations are now dated as Famennian to possibly earliest Visean. This age assessment is supported by rare conodonts and ammonoids recovered from intercalated limestones in the basal part of ‘Yali’ Formation. In the Everest region, the Devonian–Carboniferous boundary is now placed c. 10 m above the lower boundary of the ‘Yali’ Formation, which was originally suggested by Lin and Qiu (1985) to be position of the D–C boundary. Unlike western Gondwana, i.e. Bolivia and Brazil, the Himalaya-Tethys zone at the northeastern margin of Gondwana does not show obvious lithological evidence for glaciations. The new palynostratigraphic data, including information on sea-level changes reflected by variations in palynological composition and lithology around the Devonian–Carboniferous boundary allow, an interregional, approximate correlation with the classical Hangenberg Event sequence in the Rhenish Massif. The analogous Hangenberg Event sequence in South Tibet further supports the hypothesis that the rapid Hangenberg Event regression/transgression was a global eustatic event of significant magnitude. The co-occurrence of probably reworked Frasnian Geminospora lemurata and Archaeoperisaccus spores in the Himalaya-Tethys zone indicates the palaeogeographical proximity of the northern margin of Gondwana to the South China Block in the palaeoequatorial belt.
Cratonic depositional systems in the Central Montana Trough involve the Devonian--Carboniferous boundary (DCB), and reflect both subtle regional epeirogeny and significant global glacioeustatic controls. A palynologic analysis of the upper Three Forks, Sappington and lower Lodgepole formations was carried out at the classic Logan Gulch location in Horseshoe Hills. The lower Trident Member of Three Forks Formation yielded low-diversity cosmopolitan, long ranging phytoplankton and few spores species (LAs1), attributed to the middle Famennian. The upper part of the same green seaway shale yielded only leiosphaerids and Botryococcus (LAs2), along with an external mold of a clymenid ammonoid. Age-diagnostic spores Retispora lepidophyta, Verrucosisporites nitidus and Vallatisporites vallatus from middle Sappington siltstone (LAs3) indicated a Strunian LN Zone. Two more assemblages from upper Cottonwood Canyon Member (LAs4) and false Bakken (LAs5), in the lower Lodgepole Formation yielded scarce, poorly preserved spores. The presence of Waltzispora polita in LAs4 indicated a Tournaisan-Visean age.
Miospores are abundant and well-preserved in the type section of Late Devonian and Early Carboniferous strata in the Lower Yangtze Valley. Based on an extensive study of the Miospores zonation in the Late Devonian and Early Carboniferous strata in the Lower Yangtze Valley, the author holds that there exist seven Miospore assemblege zones, comprising three Late Devonian zones and four Early Carboniferous zones: 1) Rugospora flexuosa-Grandispora cornuta (FC) zone; 2) Vallatisporites pusillites-Retispora lepidophyta (PL) zone; 3) Retispora lepidophyta-Verrucosisporites nitidus (LN) zone; 4) Vallatisporites verrucosus-Retusotriletes incohatus (VI) zone; 5) Spelaeotriletes pretiosus-Cingulizonates bialatus (PB) zone; 6) Schopfites claviger- Auroraspora macra (CM) zone; 7) Lycospora pusilla (PU) zone. A palynological characterization of the Devonian-Carboniferous boundary has, until now, been based on the disappearance of Retispora lepidophyta and Vallatisporites pusillites. It is quite clear that Vallatisporites verrucosus-Retusotriletes incohatus (VI) zone should beling to Carboniferous, and the boundary between the Devonian and Carboniferous strata in Lower Yangtze Valley should be located at the bottom of the Chenjiabian Formation. The Devonian and Carboniferous miospores undoubtedly play an important role in stratigraphical subdivision and correlation as well as in reconstruction of palaeogeography, palaeontology and palaeoclimates. On the basis of palynological data, the author reassessed the age of the Guanshan Formation and assigned this formation to Late Devonian, and confirmed that the Rugospora flexuosa-Grandispora cornuta (FC) zone should correspond to the Upper part of Famennian Formation (Fa2c-Fa2d).
The miospore Retusotriletes loboziakii sp. nov. is described from rocks containing the problematic algae Protosalvinia spp. from two localities in eastern Kentucky, USA. Both sections are from the Upper Devonian (Famennian) Ohio Shale Formation. Single, dispersed specimens of Retusotriletes loboziakii sp. nov. are morphologically identical to spores within dispersed tetrads. Moreover the dispersed tetrads are identical to in situ tetrads within Protosalvinia thalli, and Retusotriletes loboziakii sp. nov. is therefore considered to be the dispersed miospore of Protosalvinia spp. Other taxa in the dispersed miospore assemblage suggest that the Protosalvinia-bearing samples investigated should be assigned to the Famennian VCo Miospore Biozone.
This paper provides a synthesis of numerous palynological investigations of the Irish Tournaisian succession undertaken between 1973 and 1985. A comprehensive miospore zonation has been established for the succession which currently serves as a standard for Western Europe. The zonal scheme comprises eight partial range/concurrent range biozones. The diagnostic elements of each biozone are described, and the distribution of stratigraphically important miospore taxa in over eighty sections is documented. Comparisons are made between the Irish miospore zonation and schemes established elsewhere in Europe; correlation is also attempted with the biostratigraphic distributions of other fossil groups, especially conodonts. A comprehensive taxonomic account of the miospore taxa encountered is provided, in which 162 taxa are described and illustrated. One new genus, Plicatispora is erected, together with sixteen new species. -Authors
There are complete sequences of Late Devonian and Early Carboniferous rocks in Nyalam, Xizang (Tibet), China, containing rich biotas. Twenty-two more samples of the Upper Devonian Zhangdon Formation and the Lower Carboniferous Yali and Naxin Formations yielded well-preserved spore and organic-walled microphytoplankton floras. Forty-eight species of acritarchs are recognized and distributed among 22 genera one of which, Yalisphaeridium, is new. The species Yalisphaeridium xizangensis, Y. baculatum and Lophosphaeridium mucronatum are described for the first time.As a result of the extensive studies of the acritarch assemblages from the Late Devonian and Early Carboniferous in Nyalam, Xizang (Tibet) it may be subdivided into three acritarch assemblage zones, one zone for the Late Devonian and two for the Early Carboniferous. Devonian and Carboniferous acritarchs undoubtedly have a role in stratigraphical subdivision and correlation, as well as reconstructions of palaeogeography, palaeoecology and palaeoclimates.
Rich phytoplankton assemblages have been obtained from Late Devonian and Early Carboniferous deposits, from a trench and three boreholes in the Holy Cross Mountains (HCM, central Poland). Almost all samples contain both acritarchs and prasinophytes. Three phytoplankton assemblages are distinguished. The first one is from the Upper Famennian, the second from the Tournaisian and the third, poorest in specimens and taxa, is from the Viséan. The assemblages are compared with coeval phytoplankton records elsewhere in the world.Some taxa from the Holy Cross Mountains are recorded for the first time in Europe. A new species Gorgonisphaeridium aesculum sp. nov. is described, and Cavatisporites microreticulatus Jachowicz is assigned to the genus Dictyotidium and renamed Dictyotidium jachowiczii sp. nov.
The predominantly volcanic Piskahegan Group has commonly been considered Early Carboniferous, based on its stratigraphic position. However, spores recently discovered in the Carrow Formation, an alluvial fan deposit in the exocaldera facies, indicate that most, if not all, of the group is of Late Devonian (late Famennian) age. The spore assemblage includes several species reported previously from Ireland, Belgium, and eastern Europe, some of them apparently restricted to the southern parts of the Old Red Sandstone Continent in Late Devonian time. Comparison of records of earliest occurrences suggests that the incoming of some species was diachronous. Volcanic rocks of the Piskahegan Group are coeval with post-Acadian, tin–tungsten-bearing granites elsewhere in New Brunswick and are considered the surface expression of plutonism that resulted from Acadian continental collison.
The present paper provides: (1) an analysis of the qualitative and quantitative compositional development of Late Devonian-Early Carboniferous palynological assemblages from the Bantry Bay and other sections of southern Ireland; (2) a scheme of successive phases, (inter) regionally recognizable in the gradual compositional development of Late Devonian-Early Carboniferous palynological assemblages; (3) a palynological zonation based on three successive assemblages zones (Retispora lepidophyta Assemblage Zone, Verrucosisporites nitidus Assemblage Zone, Spelaeotriletes pretiosus Assemblage Zone); and (4) two palaeogeographically related local phases, within the scheme of regional phases.It is concluded that: (1) the scheme of regional phases, in combination with the assemblage zones recognized, provides a more realistic tool for long-range palynostratigraphical correlation than the earlier proposed schemes of concurrent range zones; (2) the assemblage zones may be used for chronostratigraphical purposes, the boundary between the Retispora lepidophyta Assemblage Zone and the Verrucosisporites nitidus Assemblage Zone approximates the conventional Devonian-Carboniferous boundary; (3) the palaeogeographically related local phases may be considered to reflect floras of the coastal and alluvial plain, and the coastal-deltaic area, respectively; (4) within southern Ireland, the palynologically determined Devonian-Carboniferous boundary lithostratigraphically correlates with a thin mudstone unit (Claystone Member, Castle Slate Member).The taxonomical part includes: (1) an emended diagonosis of Lophozonotriletes; (2) formal proposals of new combinations of Ceratosporites delicatus, Asperispora acuta, Asperispora perlota and Diaphanospora scolecophora; and (3) the establishment of the Verrucosisporites nitidus morphon and the Dictyotriletes submarginatus morphon.
The continuous variation in a group of Late Devonian—Early Carboniferous camerate spores from southern Ireland, assigned to species of Auroraspora, Colatisporites and Endoculeospora can be denoted by recognizing the Auroraspora macra morphon. This non-typological unit is introduced by discussing: (1) the taxonomy of the constituent species [Auroraspora macra Sullivan 1968, A. hyalina (Naumova) Streel in Becker et al. 1974, A. asperella (Kedo) nov. comb. Van der Zwan, Colatisporites decorus (Bharadwaj et Venkatachala) Williams in Neves et al. 1973, and Endoculeospora gradzinskii Turnau 1975]; (2) the continuous morphological variation; and (3) the biostratigraphical application, as well as the related form Auroraspora rectiformis (Naumova) nov. comb. Van der Zwan.
Palynostratigraphy at the Devonian-Carboniferous Boundary in the Himalayan Region, Xizang (Tibet), China
- Gao
Chapter 22 - The Devonian Period
- Becker
Devonian miospores from northwestern Gondwana
- Breuer
The Late Devonian-Early Carboniferous conodonts of the Yali section from Nyalam, Qomolangma, South Xizang (Tibet)
- Qiu
Qiu, H.R., 1988. The Late Devonian-Early Carboniferous conodonts of the Yali section from
Nyalam, Qomolangma, South Xizang (Tibet). In: Chinese Academy of Geological
Sciences (Ed.), Tectonic Evolution of Lithosphere in Himalayan Region (Proceeding of
Palaeontology in Tibet). Geological Publishing House, Beijing, pp. 272-302 (in Chinese).
Upper Devonian spores from the North Tarim Basin, NW China
- Zhu
Zhu, H.C., 2000. Upper Devonian spores from the North Tarim Basin, NW China. Acta
Palaeontol. Sin. 39, 168-182.
Palynomorph taxa from the Famennian-Tournaisian of Yali section. Specimens are identified by sample number-slide number with England Finder coordinates (EF) locations. The scale bar is 50 μm
- V Plate
Plate V. Palynomorph taxa from the Famennian-Tournaisian of Yali section. Specimens are identified by sample number-slide number with England Finder coordinates (EF) locations. The
scale bar is 50 μm.
- Higgs
Acanthotriletes macrogaleatus Phillips and Clayton, 1980 (Higgs et al., 1988) (9.2-3-O2, EF: R38/1).
- Ouyang
Cyclogranisporites microtriangulus (Akyuol) Geng, 1985 (Ouyang et al., 2017) (0.7-3-O2, EF: U37/2).
Veryhachium trispinosusm
- Lei
. Veryhachium trispinosusm (Lei et al., 2013) (4. 9.2-1-O2, EF: S35/4; 5. 2.3-3-O2, EF: M45/4)
Chapter 22 -The Devonian Period
- R T Becker
- J E A Marshall
- A C Da Silva
- F P Agterberg
- F M Gradstein
- J G Ogg
Becker, R.T., Marshall, J.E.A., Da Silva, A.C., Agterberg, F.P., Gradstein, F.M., Ogg, J.G., 2020.
Chapter 22 -The Devonian Period. In: Gradstein, F.M., Ogg, J.G., Schmitz, M.D., Ogg,
G.M. (Eds.), Geologic Time Scale 2020. Elsevier, pp. 733-810.
Palynostratigraphy at the Devonian-Carboniferous Boundary in the Himalayan Region
- L D Gao
Gao, L.D., 1989. Palynostratigraphy at the Devonian-Carboniferous Boundary in the Himalayan Region, Xizang (Tibet), China. In: McMillan, H.J., et al. (Eds.), Devonian of the
World: Proceedings of the 2nd International Symposium on the Devonian System Canadian Society of Petroleum Geologists, pp. 159-170.
The Late Devonian-Early Carboniferous Miospore Zonation in the Lower Yangtze Valley, China and the Devonian-Carboniferous Boundary. Acta Geoscientica Sinica, 6-20. (northern Rhenish Massif, Germany) -a potential GSSP section
- L D Gao
Gao, L.D., 2015. The Late Devonian-Early Carboniferous Miospore Zonation in the Lower
Yangtze Valley, China and the Devonian-Carboniferous Boundary. Acta Geoscientica Sinica,
6-20.
(northern Rhenish Massif, Germany) -a potential GSSP section. Palaeobiodiversity and
Palaeoenvironments (accepted).
Stratigraphic and systematic palynology of the Tournaisian rocks of Ireland. The Geological Survey of Ireland
- K Higgs
- G Clayton
- J B Keegan
Higgs, K., Clayton, G., Keegan, J.B., 1988. Stratigraphic and systematic palynology of the
Tournaisian rocks of Ireland. The Geological Survey of Ireland, Special Paper 7, 1-93.
Carboniferous and Permian Ammonites in the Everest Region
- X L Liang
Liang, X.L., 1976. Carboniferous and Permian Ammonites in the Everest Region, Reports of
Scientific Investigations (1966-1968) in Everest Region (Palaeontology). Science
Press, Beijing (in Chinese).
Tectonic Evolution of Lithosphere in Himalayan Region (Stratigraphy of Tibet)
- B Y Lin
Lin, B.Y., 1989. Chapter 3 Devonian. In: Chinese Academy of Geological Sciences (Ed.),
Tectonic Evolution of Lithosphere in Himalayan Region (Stratigraphy of Tibet). Geological Publishing House, Beijing, pp. 40-67 (in Chinese).
The Late Paleozoic Spores and Pollen of China. Devonian-Carboniferous Boundary: introduction of the tener event
- S Ouyang
- L C Lu
- H C Zhu
- F Liu
Ouyang, S., Lu, L.C., Zhu, H.C., Liu, F., 2017. The Late Paleozoic Spores and Pollen of China.
Devonian-Carboniferous Boundary: introduction of the tener event. Geologica Belgica,
19(1-2):135-145.