Miospore Assemblages Research Articles

Facies associations of the Bathonian Hamam Formation from Northwestern Jordan

Two stratigraphic sections of the Hamam Formation (Bathonian Stage, Middle Jurassic) exposed in the western part of Wadi Zarqa region, northwestern Jordan, are described and interpreted on the basis of palynoflora and facies analysis in order to reconstruct their depositional environments and sequence stratigraphic framework, which not discussed before. Five facies associations have been identified in the Hamam Formation characterized by a mixed carbonate–siliciclastic ramp setting, ranging from incised fluvial valley fill facies, beach foreshore restricted inner ramp to high-energy shoals and mid-ramp settings. The palynoflora includes well-preserved miospore assemblages which are recorded only from the incised fluvial valley fill facies for the first time and yielded 64 miospore species belonging to 40 genera. Most of these taxa are long-ranging and have been reported from Jurassic and Cretaceous rocks worldwide, except Callialasporites dampieri, Murospora florida, Granulatisporites jurassicus, Piceites expositus, Pityosporites parvisaccatus, Leptolepidites verrucatus, and Protopinus scanicus which have short ranges in the Middle Jurassic. Furthermore, these rocks are rich in shallow-marine Neo-Tethys macro-invertebrates supporting a Bathonian age. Two third-order depositional sequences bounded by three regional unconformities at the Bajocian–Bathonian and Bathonian–Callovian stage boundaries as well as within the Bathonian are defined based upon facies characteristics and stratal geometries. A regional correlation of sequence boundaries of similar age indicates that they are eustatic in origin.

Disperse megaspores in the Lower Visean deposits of the Kaluga oblast (1P/A Aleksandrovskaya borehole)

Disperse megaspores were first found in the Lower Visean deposits of the Kaluga region (1P/A borehole). A layered distribution of the megaspores in the studied section is shown. A large number of megaspores were established in the lower part of the section of the Bobrikovskian deposits. Higher along the section, there is a trend to a decrease in the number of megaspores until they disappear completely in the Tula deposits. Two megaspore assemblages were identified. A great variety of species was observed in the lower assemblage; the dominant megaspores are Zonalesporites brasserti and Aphanozonatisporites triglobatus. The only dominant species was recorded in the upper assemblage, Zonalesporites brasserti, with a low species diversity of the entire assemblage. The miospore and megaspore assemblages that are typical of the Lower Visean in the section of the analyzed borehole are compared.

Upper Silurian miospores from the Precordillera Basin, Argentina: biostratigraphic, palaeonvironmental and palaeogeographic implications

AbstractThis study is concentrated on Ludlow (to Pridoli?) miospores from the Los Espejos Formation at the Quebrada Ancha locality, Central Precordillera, San Juan Province, Argentina. The Ludlow age is in agreement with the age based on acritarchs. The assemblage of continental palynomorphs is composed of 43 miospore species (29 trilete spores and 14 cryptospores). A new synonymy is proposed: Chelinospora poecilomorpha is here considered a junior synonym of Clivosispora verrucata. In addition, specimens belonging to C. verrucata var. verrucata and C. verrucata var. convoluta are included in a new morphon. This study represents the second Late Silurian miospore assemblage described from South America; the first was from the Urubu River, Amazon Basin, northern Brazil. The Quebrada Ancha assemblages allow a reasonably good correlation with biozones established for the Upper Silurian from the Cantabrian Mountains, northern Spain. The dendrogram analysis between coeval miospore assemblages from different localities shows a strong palaeogeographic affinity with the miospores recovered from northern Brazil and North Africa. Miospore assemblages from Spain show influences from Baltica and North Africa, demonstrating their intermediate position between these two continental plates. Conversely, dissimilarities recognized between Libya and Tunisia are most probably owing to local ecology and/or environmental conditions.

Caracterização Geoquímica e Bioestratigráfica das Superfícies de Inundação Marinha da Seção Meso-Neodevoniana, na Região de Dom Aquino (MT), Noroeste da Bacia do Paraná, Brasil

The global anoxic event in the Frasnian is well characterized in the Paraná Basin, in the upper portion of the Ponta Grossa Formation, by dark carbonaceous shales rich in organic matter. These shales are found in a section of the Ponta Grossa Formation of Meso and Neo-Devonian age, where the shales correspond to the signature of the Givetian-Frasnian transition- and, also, to the progressive drowning of the Devonian sequence in the basin. Through geochemical and biostratigraphic data obtained from the section mentioned above, it was possible to recognize flood surfaces and the maximum flooding surface in the section and, also, the progressive drowning of the Devonian sequence in the basin that reached its maximum in the Frasnian. These shales, which represent the signature of the Givetian-Frasnian transition and the maximum flooding surface, occurred in Frasnian, can be used as a chronostratigraphic marker and are also the object of interest for hydrocarbon exploration. Two miospore assemblages related to the Givetian and Frasnian and some algae of the genus Maranhites were recognized as well as acritarchs.

The palynology of the Triassic–Jurassic transition in southeastern Queensland, Australia, and correlation with New Zealand

New evidence is presented on the Triassic–Jurassic boundary in eastern Australia, based on miospore assemblages from three continuously cored drillholes which penetrated the Raceview Formation to Ripley Road succession in the eastern Clarence-Moreton Basin of southeastern Queensland. Evidence for the age of this continental succession is provided by correlation based on the first appearances of five distinctive species. These taxa first appear at or close to the Rhaetian–Hettangian boundary in the marine, ammonite-dated succession of New Zealand and in the lower Ripley Road Sandstone of Queensland. The more gradual introduction of these species in the Queensland succession, as opposed to their near-synchronous appearance in New Zealand, is probably due to their gradual migration into an inland environment in contrast to their origin from a nearshore region in New Zealand. At higher levels the first appearance of intrastriate Classopollis, closely followed by its marked increase in abundance, is regarded as evidence for correlating assemblages from the upper Ripley Road Sandstone in the eastern Clarence-Moreton Basin with the earliest Sinemurian of New Zealand. The views of some previous workers that the Hettangian of eastern Australia is characterised by the appearance of abundant Classopollis must now be modified. From the aspect of biotic change, associated with climate change at the Triassic–Jurassic boundary, this study indicates a rapid local change in New Zealand. A new type of biozone, the Association Zone, is proposed as a type of interval zone. The need for a distinctive biozone to characterise palynofloral assemblages is indicated to allow for the frequent recycling of palynomorphs and also to better define the body of an interval zone. New Early Jurassic miospore zones are proposed for southeastern Queensland. Granamegamonocolpites campbellii sp. nov. is described and one new combination, Anapiculatisporities helidonensis (de Jersey) comb. nov., is proposed. Morphological and stratigraphical evidence is provided for gradualism in the lineage development of intrastructure in Classopollis, from massive (unstructured), to intrapunctate, to intrastriate specimens.

Latest Ordovician–earliest Silurian acritarchs and chitinozoans from subsurface samples in Jebel Asba, Kufra Basin, SE Libya

Latest Ordovician–earliest Silurian Tanezzuft Formation shales recovered from core material of the shallow borehole JA-2 drilled in Jebel Asba at the eastern margin of the Kufra Basin, southeastern Libya, yielded well-diversified palynomorph assemblages with transparent and brownish to yellowish vesicles and organic matter (visual kerogen Types 1 and 2) from depth interval 46.20 to 67.82m. In addition, miospores including cryptospores, and Tasmanites sp. (“Tasmanites with nodules”), scolecodonts, and a stratigraphically significant palaeo-marker, the enigmatic, tubular organic structure Tortotubus protuberans, were also recorded frequently in most samples. Kerogen colour based on miospores (TAI <3) and chitinozoan reflectance indicate an immature facies for oil generation. The two uppermost samples (from 33.33m and 46.20m depths) and the lowermost ones (from 67.92 to 73.21m depth) contain rare palynomorphs and other organic remains and have been partially affected by oxidation.Furthermore, palynological and palynofacies analyses were carried out on cuttings from an old well (UN-REMSA well), ca. 530m towards the NNE from well JA-2. The composition of the organic residue is similar in both wells. However, the UN-REMSA well yields fairly numerous chitinozoans, scolecodonts and biofilms but lacks the “thread-like structures” and “Tasmanites with nodules” observed in well JA-2.All the investigated samples in well JA-2 are dominated by a single chitinozoan species, Euconochitina moussegoudaensis Paris (in Le Hérissé et al., 2013). Based on correlation with chitinozoan-bearing strata around the Ordovician–Silurian boundary, the analysed samples from well JA-2 and from the UN-REMSA well are regarded as post-glacial, but still of either latest Hirnantian age, or at least no younger than earliest Rhuddanian. A well-diversified acritarch, miospore and cryptospore assemblage recorded in well JA-2 supports a marginal marine (nearshore) depositional environment. This assemblage is no older than earliest Rhuddanian yet the latest Hirnantian age of the assemblage cannot be completely ruled out as our current knowledge on the post-glacial, latest Hirnantian acritarch and miospore assemblages is poorly documented in North Africa.

Miospore distribution and sedimentological facies distribution as an insight to changing terrestrial palaeoequatorial floral communities during a Pennsylvanian glacio-eustatic sea level cycle

Systematic trends in miospore assemblages are known to characterise systems tracts in Carboniferous successions and could relate either to changing delivery mechanisms or to the influence of fluctuating sea levels on coastal plain vegetation. A succession of deltaic Pennsylvanian mudstones exposed in the UK Pennine Basin provides a record of continuous sedimentation at a location that remained submerged through a complete glacio-eustatic sea level cycle. Changing sedimentological facies, identified from thin sections enable the succession to be linked to an existing sequence stratigraphic framework and provide a context for the miospore trends through the succession. An abundant and diverse microflora is present in all samples examined. Detailed palynological and palaeoecological analyses have identified some significant trends and key taxa at important stratigraphic surfaces. This succession has provided a rare opportunity to study miospore assemblages in the late highstand and the lowstand systems tracts that are normally either removed by erosion or represented by sandstones. In the mid-late highstand, forest mire abundances (dominated by Lycospora) peak at 81.75% falling to 39.5% in the early lowstand, suggesting that lycopsid-dominated forests characterised coastal plains in the highstand and that there was a major floral turnover during significant sea level falls. The early lowstand sand- and silt-bearing mudstones are also associated with an abrupt increase in Florinites, Calamospora, Punctatisporites and Spelaeotriletes arenaceus. Maximum flooding surfaces, characterised by clay-rich lenticular mudstone facies, have some similar miospore characteristics to the sequence boundaries, including low abundances of the forest mire group and peaks in Punctatisporites, but are distinguished by high abundances of upland miospores. Changes in the diversity and abundance of miospores through the studied section appear to relate to their location within the stratigraphic framework, rather than directly to the facies and sedimentary processes. Therefore the greatest control on miospore trends and distributions appears to be sea level changes influencing vegetation in the coastal areas rather than the depositional mechanisms transporting sediment on to the shelf.

Carboniferous palynology in Midcontinent North America

Palynofloras derived mainly from coal beds in the Illinois and Midcontinent basins show distinct trends in taxonomic composition and dominance up through the succession, with only minor differences between the basins. The few studied Upper Mississippian (Chesterian) coals are dominated by Lycospora, with other genera represented, including Schulzospora. Morrowan coals are dominated by several species of Lycospora, with many other genera and species represented, including first appearances of Laevigatosporites and Florinites, and the last occurrence of Schulzospora. Atokan coals are also dominated by various species of Lycospora, but are characterized by the appearance of many new taxa, including Endosporites globiformis and Microreticulatisporites nobilis at the base. Desmoinesian coals show decreasing spore diversity and decreasing dominance of Lycospora, with some coals dominated by fern spores, including the first appearance of species of Thymospora at the base. Missourian and Virgilian coals show an abrupt decrease in diversity at the Desmoinesian-Missourian boundary, with disappearance of Granasporites and near disappearance of Lycospora, which dominated miospore assemblages in the Early and Middle Pennsylvanian. Seed fern and tree fern spores became the most abundant miospores in the Late Pennsylvanian.

Pennsylvanian (Namurian and Westphalian) miospore assemblages from the west coast of Scotland

Examination of cored borehole sections of Pennsylvanian sediments in the Machrihanish Coalfield on Kintyre and samples from coastal exposures at Inninmore Bay on the Sound of Mull, demonstrate the existence of Westphalian (Langsettian to Bolsovian) sediments in both close proximity to the Highland Boundary Fault zone and in isolated outliers within the western parts of the Scottish Highlands. Earlier studies suggested a Duckmantian to Bolsovian age for the Inninmore Bay sections and the investigation of material from new sections in the area confirms this stratigraphical range. The borehole sections in the Machrihanish Coalfield demonstrate the unconformable relationship between the probable Namurian to Westphalian sediments of the Scottish Coal Measures Group and the underlying early Namurian Limestone Coal Formation. In addition to rich assemblages of western European miospore taxa, the Machrihanish populations contain examples of species such as Columinisporites ovalis, Paleospora fragila, Spackmanites irregularis and Vestispora colchesterensis which are characteristic of North American assemblages. The distinctive species Playfordiaspora cancellosa is reported from the British Carboniferous.

Основные этапы формирования палинофлоры в уфимское и казанское время в северо–западной части Тимано–Печорской нефтегазоносной провинции

Results of the palynological study of the Lower-Middle Permian terrigenous deposits of the NorthWest part of the Timan-Pechora petroleum province (from the wells 1-Narjan-Mar, 140-Kolguev, Peschanoozorskaya 1/4, Severo-Zapadnaya 202) are presented. Three miospore assemblages are established. They characterize the main stages of the palynofl ora in the Ufa and Kazan time and allow to reconstruct paleoclimatic conditions in this territory.

Diverse assemblages of Mid Devonian megaspores from Libya

A restudy of Devonian palynological assemblages of samples from the A1-69 borehole, drilled in the Ghadamis Basin, western Libya, North Africa has led to the discovery of numerous well-preserved megaspores amongst abundant miospores, rare acritarchs and rare chitinozoans. Thirteen samples from base to top, 1496 ft (456 m) up to 965 ft (294 m), contain the richest Devonian megaspore assemblages from northwestern Gondwana. The section is dated by a rich diverse miospore assemblage indicating the presence of the upper part of the AD pre-Lem Biozone up to the lower part of the TCo Oppel Zone, ranging from a latest Eifelian or earliest Givetian age up to a latest Givetian or an earliest Frasnian age. Seventeen megaspore taxa have been identified. Among them, two new species ( Biharisporites lugardonii and Lagenicula milleri) and four new varieties ( Corystisporites acutispinosus var. acutispinosus and var. bullatus, Heliotriletes longispinosus var. longispinosus and var. radiatus) are described. One new possible megaspore species is also described: Verruciretusispora labiosa sp. nov. One core sample (1293 ft, 394 m) contains several specimens of very large megaspores (ca. 1 mm), the largest known from Devonian localities (except for one specimen observed in the Givetian from Belgium). Among the 17 megaspore taxa from Libya, 6 are present on the Euramerican Continent. This observation is in accordance with previous palynological conclusions that favour the absence of palaeogeographic barriers between the Euramerican and Gondwanan continents that are suggested to be grouped together in a “Pre-Pangea” land mass.

Was the latest Devonian glaciation a multiple event? New palynological evidence from Bolivia

Assemblages of acritarchs, prasinophytes, and miospores were recovered from the uppermost Iquiri and lower portion of the Itacua formations in southeast Bolivia. Analysis of the diverse and somewhat abundant well-preserved palynomorph assemblage indicates a Late Devonian (late Famennian) age for both formations, and further subdivision in ascending stratigraphic order into the ?VCo, LL, LE, and LN miospore biozones of Western Europe. The presence of age-diagnostic miospore taxa from South America and North America indicates contemporaneous glaciation events between these two regions. The results from close sampling of the diamictite facies of the Itacua Formation at the Bermejo West section, Bolivia, correlate the latest Famennian spore inceptions used to define the Euramerica miospore biozone sequence (LL, LE, and LN zones). The Itacua Formation diamictite sequence examined is relatively thin compared to other diamictite sequences in Bolivia. Furthermore, the miospore biozones represent an estimated duration of three million years, whereas orbitally-forced glacial-interglacial events (e.g., Ruddiman, 2001) are of the Milankovitch frequency range of between 20,000 and 400,000 years. Therefore, it seems most likely that a number of glacial/interglacial events are represented, rather than a single glacial episode.

The Gondwana–Laurussia convergence process: evidence from the Middle Mississippian (Viséan) palynostratigraphic record

AbstractThe Gondwana–Laurussia convergence process can be explored by studying the Middle Mississippian (Viséan) palynoflora of northwest Africa. Statistical analysis of the Viséan miospore assemblages reported from Morocco defines two populations, one with clear Laurussian affinity from the northern margin of the Western Meseta, and the other, more Gondwanan in composition, from the southern part of the Western Meseta and Anti-Atlas. Moreover, no transitional assemblages have been described from the region. These palynofloral variations are a consequence of the complex palaeogeography of the northwest African margin, which was controlled by the Variscan Orogeny during Viséan times. Taking into consideration the palynofloral affinity of the miospore assemblages reported throughout the entire North African margin and the Middle East, it is possible to envisage a Late Carboniferous Pangaea amalgamation process initially evolving from the west, while in the east the ocean separating Gondwana and Laurussia persisted as an effective barrier to floral migration.

Morphological variation and distribution of the Tournaisian (Early Mississippian) miospore Waltzispora lanzonii Daemon 1974

Mississippian strata of the Amazonas Basin, northern Brazil, contain abundant and diverse assemblages of miospores, many of considerable stratigraphie importance. These include an acavate trilete species - Waltzispora lanzonii - which is the subject of the present account. Based on numerous specimens from the Tournaisian (Lower Mississippian) Oriximina Formation, the morphology of the more typical and also the relatively rare, aberrant representatives of W. lanzonii is illustrated and described in detail. Current and previously published data indicate that the species is restricted palaeogeographically to north-northwest Gondwana; i.e., incorporating parts of presentday northern Brazil, Peru, and the Sahara region of Algeria and Libya. Chronostratigraphically, W. lanzonii is characteristic of and perhaps entirely confined to Tournaisian strata, although the possibility exists that it may extend slightly higher, into the Visean. However, rare occurrences of the species in upper Visean strata are considered to be a probable consequence of reworking.

Palynology of the Toarcian–Aalenian Global Boundary Stratotype Section and Point (GSSP) at Fuentelsaz (Lower–Middle Jurassic, Iberian Range, Spain)

The Fuentelsaz Section is located in the Castilian Branch of the Iberian Range (Guadalajara, Spain). Its exceptional Lower–Middle Jurassic transition outcrops led to its designation as the Global Boundary Stratotype Section and Point for the base of the Aalenian. The sediments of the Toarcian–Aalenian transition at Fuentelsaz are composed of marls with interbedded limestones in rhythmic alternation. Marls are dominant in the Toarcian and the Opalinum Zone up to the middle part of the Comptum Subzone. In the remaining Comptum Subzone, marly materials are scarce and limestones predominate. Sedimentation at Fuentelsaz took place over an extensive marine epeiric carbonate platform that was well connected with the open sea. In the Fuentelsaz Section, a total of 43 palynomorph taxa were recorded: 23 spore taxa, 13 pollen taxa, 4 acritarchs, 2 prasinophytes and 1 dinoflagellate cyst. The studied sediment samples were always dominated by terrestrial allochthonous miospores. In general, miospore assemblages are biased due to the transport of pollen from land or islands to the continental platform. Spheripollenites, Classopollis or indeed both pollens numerically dominate the assemblages. Other miospores appear in low numbers. Aquatic palynomorphs are also scarce; Micrhystridium lymensis is the most common. Five palynological assemblages (PA) were distinguished: PA1, PA2 and PA3 are Toarcian in age, PA4 is located at the boundary between the Toarcian and the Aalenian and PA5. This latter palynological assemblage which is lower Aalenian in age shows a strong reduction in palynomorph diversity and preservation in the Comptum Subzone. Palaeoecological analysis of the palynomorphs indicated the presence of calm, oligotrophic sea water. The palaeofloral communities of gymnosperms and vascular cryptogams—which grew in subtropical arid conditions—were poorly diversified.

Palynostratigraphy and vegetational changes in the Siluro-Devonian of the Ghadamis Basin, North Africa

This study, based chiefly on cryptospores and trilete spores from North Africa (MG-1 borehole, Ghadamis Basin, southern Tunisia), contributes to the understanding of the terrestrialization process, its timing and its palaeoenvironmental consequences across the Silurian–Devonian transition in Western Gondwana. The investigated section comprises, in ascending stratigraphic order, the Tanezzuft, Acacus and Tadrart formations. Four well preserved and diversified miospore assemblages are recognized and attributed respectively to the late Gorstian–Ludfordian, Lufordian–early Přídolí, Přídolí and early Lochkovian, based on correlation with previously established palynozonations, and independent age evidence from chitinozoan faunas. The lithostratigraphical boundary between the Acacus and the Tradart fms. corresponds to the Silurian–Devonian transition. In this time span, the Ghadamis Basin was the site of an extensive regression. The middle Silurian–Lochkovian Tunisian miospore assemblages do not differ significantly from coeval associations both from Gondwanan and Laurussian localities, hence they do not provide evidence for a pronounced palaeobiogeographical differentiation. This similarity could reflect: a) palaeogeographical proximity of the two palaeocontinents and b) the low diversity of primitive vegetation in its early stages of evolutionary development. Minor but distinct variations in taxonomic composition of assemblages belonging to the same palaeogeographic domain, are thought to reflect varying environmental or physiographic conditions at regional and/or local scale.

The Upper Triassic of northern Middle Siberia: stratigraphy and palynology

The Lower Carnian succession in northern Middle Siberia includes continental and marine deposits. Bivalves, nautiloids and ammonites in the marine units provide biostratigraphic control for a palynological study of three important sections. Palynomorph associations from the base of the succession include forms that have previously been reported only from Norian and Rhaetian deposits in the Tethyan and Boreal realms. This suggests that, in comparison with other areas, the palynoflora of Siberia was more uniform throughout the Late Triassic, and that the Carnian and Norian stages have a miospore assemblage that is recognizable in a wide belt through Arctic Canada and northern Eurasia.

The palynology of the Hannibal Shale (Mississippian) of Northeastern Missouri, U.S.A. and correlation with Western Europe

Mississippian palynomorphs have been recovered from two successions of the Hannibal Shale in Missouri, U.S.A., which is the lowermost Carboniferous unit in the Mississippi Valley. The assemblages are dominated by acanthomorph acritarchs, with Micrhystridium stellatum being the principal species. The miospore assemblages are well‐preserved and of low taxonomic diversity. They are dominated by long‐ranging taxa that survived the latest Devonian mass extinction event. This assemblage closely resembles assemblages assigned to the Vallatisporites verrucosus‐Retusotriletes incohatus (VI) Biozone of Western Europe. However the assemblage from the Mississippi Valley is relatively impoverished in comparison with European assemblages, and many key European zonal taxa are absent. Independent biostratigraphic correlation suggests that the Hannibal Shale is equivalent to the VIBiozone, the Cristatisporites hibernicus‐ Umbonatisporites distinctus (HD) Biozone, and possibly the lowermost part of the Spelaeotriletes balteatus‐Rugospora polyptycha (BP) Biozone in Europe. This indicates the relatively condensed nature of the succession. Palynofacies analysis suggests a shelf to basin depositional environment for the Hannibal Shale; this is consistent with the paleogeographic location of this area during the Early Carboniferous.

The ecology of Upper Westphalian microflora from Dobrudzha Coal Basin, Bulgaria

The study is based on coal samples from Makedonka, Krupen and Gurkovo Formations. More than 55 specimens were collected, which represent the Westphalian plants and have been recorded in the field for ecological purposes. This research considers the evolutionary and phylogenetic importance of the fossil plants identified, where determination of the composition and distribution of the miospore assemblages allows reconstruction of the flora. The study provides important information on the detailed structure of coal swamp vegetation. Global climate changes, mainly droughts, have forced vegetational changes, resulting in seed-plant world domination. The current result helps to assess the role of the different plant groups (microfloristic assemblages) in the shaping of terrestrial ecosystems over time, and provides insight into the origins of modern day terrestrial biodiversity.

Late Carboniferous–Early Permian palynology of Baode (Pao‐te‐chou) in Shanxi Province, North China

AbstractThe Late Carboniferous–Early Permian strata cropping out in northern Shanxi Province, China contain a continuous and varied fossil record, making this succession a classical locality for the study of palynology during that interval in North China. Abundant, diverse and well‐preserved miospores are recorded and illustrated from the Penchi Formation to the Shansi Formation, comprising 191 species assigned to 67 genera, as well as some scolecodonts. Three new species (Neoraistrickia leiclavatus sp. nov., Indospora verrucatus sp. nov., Balteosporites tomentosus sp. nov.) are proposed.According to the first appearance of a few selected species and the changes of palynological abundance in the succession, four miospore assemblage zones have been recognized in ascending order, viz., the Torispora securis–Torispora laevigata (SL) Assemblage Zone, the Torispora verrucosa–Pachetisporites kaipingensis (VK) Assemblage Zone, the Thymospora thiessenii–Striatosporites heyleri (TH) Assemblage Zone and Platysaccus minus–Gulisporites cochlearius (MC) Assemblage Zone. With evidence from microfossils (mainly fusulinids and conodonts), the age of these assemblage zones can be determined approximately. The SL Zone described here is roughly equivalent to the SL Zone established by Clayton et al. (1977) in Western Europe, indicating an age of Westphalian C‐D (Moscovian). The VK Zone ranges from Stephanian A‐Autunian (Kasimovian‐late Gzhelian); however, it only includes the elements of the OT Zone (Clayton et al. 1977) which usually occur from Westphalian D to Stephanian A (late Moscovian‐early Kasimovian) in Europe. Microfaunal evidence also shows that the age of the TH and MC zones should be Early Permian, but their components are evidently different from those derived from other coeval assemblage zones around the world. This discrepancy can be explained by environmental differences occurring during that interval, which were brought about by the Hercynian tectonic event. Using biostratigraphical zonations of other microfossil groups, a palynological Carboniferous–Permian boundary in N. China can be located within the miospore succession. The miospore assemblage zones proposed in this paper are also compared with zonations proposed by earlier studies in N. China and other parts of the world. Copyright © 2008 John Wiley &amp; Sons, Ltd.