Palynological Assemblages Research Articles

Pleistocene vegetation in Guangxi, south China, based on palynological data from seven karst caves

Pleistocene cave deposits usually provide ideal materials for the study of mammals. Karst caves in Chongzuo, Guangxi Zhuang Autonomous Region of south China are famous for numerous studies on their abundant mammalian fossils and most importantly, Homo sapiens. Unfortunately, the environmental backgrounds, e.g. vegetation and climate, that governed these faunas, are usually lacking because there is no appropriate proxy. In this work, we analysed the palynological assemblages from seven well-dated karst caves in Chongzuo. The ages of these seven caves (2.0–0.11 Ma) cover almost the entire Pleistocene. Though the number of pollen and spores is comparatively low, as expected, we managed to reconstruct the principle vegetation types. The results show that the individual vegetations were mainly warm temperate to subtropical evergreen and deciduous broad-leaved mixed forests. The present study provides important background environmental information on the Pleistocene faunas and Homo sapiens in Guangxi, south China.

Palynological record of the Cretaceous ZKD14 core (Songliao Basin, Northeast China) and its paleoclimatic significance

AbstractTo better understand the vegetation and possible paleoclimate change, we recovered a palynological record obtained from the ZKD14 core covering from the Sifangtai and Mingshui Formations in the northern Songliao Basin, northeastern China. Based on the abundance and variations in determined palynomorphs, two palynological assemblages can be distinguished, including Schizaeoisporites–bisaccate–Tricolporopollenites and Taxodiaceaepollenites–bisaccate–Tricolporopollenites. These palynological assemblages are assigned to the late Campanian–Maastrichtian stage based on the geological range of some important elements and the correlation with relevant assemblages of other areas. In this paper, we applied a sporopollen–climate transforming methodology, which uses the percentage of xerophytic and thermophilic taxa to indicate stratigraphic trends of humidity and temperature, respectively. Then two vegetation and paleoclimate phases were reconstructed based on the ecological habits of the parent plant, as well as the abundance variation in xerophytic and thermophilic taxa: (i) The vegetation type was interpreted to reflect a mixed conifer forest with varying pteridophytes landscape, presenting a hot and arid subtropic climate during the Sifangtai to lower part of member 2 of the Mingshui Formations. (ii) The vegetation type was characterized by a conifer‐dominant landscape. Accordingly, the climate turned more humid and colder during the upper part of member 2 of the Mingshui Formation. The global cooling event (Campanian–Maastrichtian Boundary Event: CMBE) which occurred between 72.0–70.0 Ma appears to have an important influence on the climatic condition of Songliao Basin.

Amber- and plant-bearing deposits from the Cenomanian of Neau (Mayenne, France)

A new Cenomanian amber- and plant-bearing deposit has been discovered at Neau, in the Mayenne department (France). The Cenomanian fossiliferous lignites are located in karst filling in a substratum of Cambrian limestones. The amber corresponds mainly to tiny millimetric grains, devoid of arthropod inclusions, but rich in microorganisms, especially the sheated bacteriaLeptotrichites resinatus, and containing pollen grains (Classopollis) and wood fibers (Araucariacae or Cheirolepidiaceae). The lignites provide abundant conifer and ginkgoale cuticle fragments (Frenelopsis,Eretmophyllum) and a lot of palynomorphs (e.g. Gleicheniidites senonicus,Cyathidites,Deltoidospora,AppendicisporitesandCicatricosisporites). The chemical signature of the amber suggests it was produced by conifers of the extinct family Cheirolepidiaceae. According to the palynological assemblage, the age of the lignites is upper lower Cenomanian or lower mid Cenomanian. The deposit environment corresponded to the upstream portion of a mangrove or the most inner part of a lagoon.

Organic Geochemistry, Petrography, Depositional Environment and Hydrocarbon Potential of the Eocene Coal Deposits of west Daranggiri Coalfield, Meghalaya

Abstract The Eocene coal deposits of west Daranggiri coalfield of Meghalaya is hosted in the Tura Formation. The coals are perhydrous in composition, rich in organic matters and poor in mineral content. The organic matters are dominantly represented by Type III kerogens contributed by terrestrial plants. Petrographic analysis confirms dominance of vitrinite with subordinate amounts of liptinite and inertinite. Maturity parameters like vitrinite reflectance, Rock-Eval Tmax, volatile matter content etc. indicate low thermal maturity of the coal within lignite to subbituminous rank. The coals are immature to act as petroleum source rock despite having high-quality organic matters. However, perhydrous nature of the organic matters and significant amount of liptinite macerals suggest that despite low thermal maturity, the coals might have some capacity to generate liquid hydrocarbon. High liptinite and perhydrous vitrinite contents of the coal may result in suppression of vitrinite reflectance, thus, underestimation of maturity. Presence of exsudatinite in the coal also points to generation of some liquid hydrocarbon. The coal deposits possess excellent potential for hydrogenation industry. The coals are characterized by very high rate of conversion from coal to oil and high oil yield. Indices of facies critical maceral association indicate the origin of the coal in wet swamps under mildly oxic to the anoxic environment with moist hydrodynamic condition. The high sulphur content of the coal, association of marine palynological assemblage and presence of limestone beds at the top of the Tura Formation point to nearshore environment of deposition.

Organic facies and palynology from the middle to late Devonian of the Pimenteiras Formation, Parnaíba Basin, Brazil

A detailed study of organic facies and palynological assemblages was carried out on 11 samples of potential hydrocarbon source rocks of the Pimenteiras Formation, an outcropping at the western edge of the Parnaíba Basin, Brazil. The main objectives are to characterize the depositional paleoenvironment and hydrocarbon source potential. The selection of this outcrop occurred in the function of its preservation and accessibility, and the samples collection observed 1 m of vertical spacing. Generally, the organic matter and the palynomorphs showed a good state of preservation and fluorescence. The most notable spores and acritarchs and phycomates species were discussed in light of international biozones, and the chronostratigraphic range defined as Late Eifelian - Latest Frasnian in age. TOC results show ranges from 0.40 to 2.91%, with most samples showing greater than 1%, thereby holding a high potential generation. The S1 values were virtually null, and the S2 peak ranged from 0.9 to 5.33 mg/g. The kerogen 435 °C, and the ICE between 4.0 and 4.5 demonstrating the material immaturity. For the palynofacies associations definition, only 10 out of the 25 total quantified of subgroups of kerogen categories were considered in the counting of 300 particles. A dendrogram constructed based on these results through cluster analysis, revealed four palynofacies, as follows: I constituted mainly by palynomorphs (acritarchs, prasinophytes and sporomorphs); II – Dominance of Translucent organic matter (cuticles, epidermal tissue and translucent phytoclasts with and without structure); III - Dominance of Opaque/non-fluorescent (opaque phytoclasts and non-fluorescent AOM) and IV - Dominance of AOM fluorescent (amorphous organic matter with fluorescence). The palynomorphs are the most abundant constituents of all studied kerogen. Quantitative analysis based on the distribution of palynomorphs groups throughout the section indicates the dominance of sporomorphs in the palynological assemblages from the Middle Devonian aged samples. On the other hand, occurred the predominance of microplankton elements in the Late Devonian aged samples. Thus, the depositional paleoenvironment was established as a distal oxic mud-dominated shelf with the deltaic influence of the Late Eifelian to Late Givetian, and there is a tendency distal (dysoxic-anoxic ‘shelf’) from the Frasnian, which indicates the maximum flooding surface.

Palynology from the Cenomanian Mata Amarilla Formation, southern Patagonia, Argentina

The critical climatic changes that occurred during the Albian–Turonian Cretaceous interval led to a major biotic turnover, both in terrestrial and marine ecosystems. Several large-scale palynological works have been conducted in the Northern Hemisphere, but information for the Southern Hemisphere remains scarce. Particularly for southern South America, there are only a few palynological works focused on this important time interval. We report here, a diverse palynoflora recovered from the Cenomanian Mata Amarilla Formation, southern Patagonia, Argentina. The palynological assemblage is composed of 64 species within 47 genera. Three new species are here defined: Polycingulatisporites multiverrucata sp. nov., Clavatisporites cenomaniana sp. nov. and Collarisporites minor sp. nov., and 18 species are first recorded for southern South America. Cluster analysis including several Albian–Turonian palynofloras of middle and high latitudes of eastern and western Gondwana show that Patagonian palynofloras are clustered together, sharing a great compositional similarity, but with features common to those of the Antarctic Peninsula and New Zealand. The Mata Amarilla Formation palynofloras here presented show characteristics of the Cyclusphaera psilata-Classopollis Sub-province, extending its stratigraphic range into the Cenomanian. This palynoflora fits well with the evolutionary scheme of angiosperms previously proposed for Argentina, and adds a new characteristic taxon (cf. Dichastopollenites sp.). The presence of Albian–Cenomanian megaspore species (Arcellites disciformis and Balmeisporites sp. cf. B. holodictyus), the abundance of common elements of the Early Cretaceous Patagonian assemblages (e.g. Classopollis and Cyclusphaera), and the relative scarcity of angiosperm pollen grains support a Cenomanian age for the Mata Amarilla Formation.

Palynological analysis of dental calculus from Pleistocene proboscideans of southern Brazil: A new approach for paleodiet and paleoenvironmental reconstructions

The proboscidean Notiomastodon platensis is widely recognized in the Pleistocene of Brazil, but direct evidence for its feeding behavior is scant. In this paper, we report palynological assemblages preserved in dental calculi to infer dietary preferences and habitats. Molar specimens (m1 and M3/m3) with significant calculus accumulation were examined from localities along the Coastal Plain (CPRS) and the Campanha region (western state in Pampa biome) in Rio Grande do Sul state, southern Brazil. Palynomorphs obtained from calculus were identified with light microscopy, and we applied species distribution modelling (SDM) for arboreal/shrub pollen taxa to investigate the environmental contexts for proboscideans during the Last Interglacial (LIG, 120 ka BP) and Last Glacial Maximum (LGM, 21 ka BP). Pollen assemblages indicate a generalist diet for N. platensis, and corroborate previous paleoecological studies. N. platensis from CPRS showed two patterns: the subadult individual was a specialized browser in wooded habitats, inferred from pollen taxa dominated by arboreal species (mainly Myrtaceae), while mature/senile adult individuals were dominantly grazers to mixed-feeders in open habitats inferred from herbaceous pollen (mainly Cyperaceae) mixed with woody elements. For the Campanha region, diet interpretation is difficult due to the absence of pollen; however, Poaceae phytoliths indicate that grasses may have been important food items, notably pooid C3 grasses. N. platensis potentially accessed a more heterogeneous environment with mixed open grasslands and forests around the LIG interval because of the larger extension of forest at the time. Grassland landscapes could have been more foraged by proboscideans around the LGM given the dry and cold climate conditions, which resulted in a northward retraction of forest.

Palynostratigraphy and genesis of upper cretaceous and Cenozoic deposits in the southern part of the Kulunda depression, Altai region

The results of palynological and micropaleontological study of Upper CretaceousCenozoic strata exposed by boreholes (BH) 23 and 19 of the Aleisk Square (Altai Region) are presented. The obtained data allowed to substantiate the age of deposits, to make assumption about its depositional conditions and to clarify the division of the section into suites. Two palynological assemblages were established in the Cretaceous part of the BH 23 section: the first characterizes the Lenki Formation and dates by SenomanianTuronian, the second one is revealed in the Upper-Sym Subformation and dates by the Maastrichtian. The Paleogene Ostrovnoye Formation of continental genesis lies on the Upper Cretaceous sediments. In BH 23 and BH 19, this formation contains spore and pollen spectra of presumably Late PaleoceneEarly Eocene and Middle Eocene age respectively. According to palynological data, the Late Miocene age of the sediments at the upper part of BH 23 section and its affiliation to Pavlodar Formation have been substantiated. The structure of palynological assemblages, features of macerate and the absence of foraminifera indicate the continental genesis of the Upper CretaceousPaleogene sediments common in the southern part of the Kulunda Depression of the Altai Region.

A new Hauterivian palynoflora from the Vale Cortiço site (central Portugal), and its palaeoecological implications for western Iberia

Abstract Palynofloral assemblages are an invaluable source of information about the interactions between fossil plants and their environments. Here we describe a new Early Cretaceous palynoflora from the Lusitanian Basin in the Estremadura region of central western Portugal. A palynological assemblage of 28 genera and 40 species was extracted from 14 samples collected in the Vale Cortiço clay pit complex near the small village of Ameal (Torres Vedras Municipality). The source is a dark grey mudstone layer belonging to the lower part of the Santa Susana Formation, which is considered to be of early Hauterivian age. The palynoflora is dominated by fern spores and gymnosperm pollen. Bryophyte and lycophyte palynomorphs are also present but subordinate. Angiosperm pollen and algal or dinoflagellate cysts were not recognised in the studied samples. The palynological assemblage represents mixed conifer forest with the ground cover and understorey vegetation dominated by ferns, with patchy occurrences of bryophytes and lycophytes. A riverine environment with surrounding vegetation of open woodland and ground cover primarily of ferns is strongly indicated for the region.

Integrated Biostratigraphy, Depositional Setting and Geochemical Analyses for Petroleum Potential Evaluation of the Lower Cretaceous (Barremian – Albian) Strata of the Koppeh‐Dagh Basin, Northeastern Iran

The lower Cretaceous rock units of the Koppeh‐Dagh Basin of northeastern Iran were investigated here in terms of biostratigraphy, depositional setting and geochemical analyses to find out if they, alike other parts of the world, are rich in petroleum. For this purpose, a stratigraphic framework is established using calcareous nannofossil and palynological elements. A nannoplankton zonation based on which subzones of the zones CC7 – CC8 of Sissingh (1977) and their equivalent NC6 – NC8 of Roth (1978) was established indicating a Late Barremian–Albian age. Palynological assemblages led us to establish the local palynozone of Odontochitina operculata. A dominantly marginal basin to a transitional zone between shelf and basin under a dysoxic–anoxic condition with low to moderate sedimentation rates coincided with a gradual sea level rise was introduced as the environment of deposition for the strata via interpretation of the palynological parameters and quantitative palynology. The obtained data from Rock‐Eval pyrolysis in compilation with palynofacies analysis reveals that the studied succession contains mainly gas‐prone type III kerogen. The Spore Coloration Index (SCI) alongside with the Rock‐Eval pyrolysis results (low values of HI and TOC) proves that these rock units locally produced natural gas during the time under consideration.

Palynostratigraphy and Genesis of the Upper Cretaceous and Cenozoic Deposits in the Southern Part of the Kulunda Depression, Altai Region

The results of palynological and micropaleontological studies of the Upper Cretaceous–Cenozoic strata penetrated by Boreholes 23 and 19 of the Aleiskaya area (Altai krai) are presented. The obtained data allowed us to substantiate the age of the deposits, make suggestions concerning their depositional environment, and to clarify the subdivision of geological section into formations. Two palynological assemblages were recognized in the Cretaceous part of the Borehole 23 section: the first one characterizes the Len’ki Formation and is dated as Cenomanian–Turonian; the second one is recognized in the Upper Sym Subformation and is dated as Maastrichtian. The Upper Cretaceous sequence is overlain by the terrestrial Ostrovnoe Formation (Paleogene). In Boreholes 19 and 23, this formation contains presumably Late Paleocene–Early Eocene and Middle Eocene spore and pollen spectra, respectively. Palynological data substantiate the Late Miocene age of sedimentary strata in the upper part of the geological section of Borehole 23 and their belonging to the Pavlodar Formation. The structure of the palynological assemblages, the specific features of the macerate, and the absence of foraminifers indicate the continental genesis of the Upper Cretaceous–Paleogene sedimentary deposits in the southern part of the Kulunda Depression in Altai krai.

Palynological Profile and Depositional Environment of the Ishim Formation (Upper Miocene) in Tobol–Ishim Interfluve, Western Siberia

For the first time, sections of the Upper Miocene Ishim Formation in the south of Tyumen oblast near the villages of Pyatkovo, Masali and Bigila were thoroughly studied by the palynological method. A series of mineralogical analyses of these sediments and radiocarbon analysis of the Quaternary sediments overlying the Ishim Formation were carried out. Four palynological assemblages (PA) were established in the Ishim Formation: PA1 with Botryococcus; PA2 with Botryococcus and Sigmopollis; PA3 with Alnus, Polypodiaceae, Botryococcus, and Sigmopollis; PA4 with Betula, Alnus, and Corylus. The layers with PA1, PA2, and PA3 were observed in two sections near Masali and Bigila. PA4 was found in sands and aleuropelites in the outcrop near Pyatkovo; it contained a significant amount of diverse pollen of temperate thermophylic broad-leaved taxa and scarce elements typical of Miocene (Taxodiaceae, Nyssa, and Tsuga). PA3 and PA4 were compared to the known complexes of Neogene sediments in Western Siberia. PA5 with Betula, Herbae, and Fungi was discovered in the bedded silts overlying the Ishim Formation in Masali outcrop. Previously, these sediments were attributed to the Late Miocene Pavlodar Formation. The composition and the structure of PA5 suggested Quaternary age of the hosting sediments. Radiocarbon analysis of the organic substance occurring in the silts has shown that these sediments were accumulated in the Late Pleistocene (Sartan Ice Age). For the first time, the information about microphytoplankton (Botryococcus, Pediastrum, Zygnemataceae, Sigmopollis) and other non-pollen palynomorphs contained in the Ishim Formation (Upper Miocene) and in Pleistocene sediments is presented. Development stages of the Late Miocene Ishim Basin were distinguished, the vegetation surrounding this basin was described, and the depositional environment of Pleistocene sediments (Masali outcrop) was reconstructed using palynological data.

Palynological indicators of palaeoenvironmental perturbations in the Basque-Cantabrian Basin during the latest Cretaceous (Zumaia, northern Spain)

Abstract The latest Cretaceous palynological assemblages from the southern margin of the Basque-Cantabrian Basin (northern Spain, Zumaia) are dominated by black opaque equidimensional phytoclasts, black opaque blade shaped phytoclasts and translucent gold-orange to brown phytoclasts. Deep water dinoflagellate cysts Cannosphaeridium utinensis and Pterodinium spp. constitutes a part of the assemblages throughout the whole succession. This record and previous study suggest deposition of the Zumaia section in the marine bathyal conditions, in relative close proximity to the land. Palynofacies analyses yields increased abundance of Leiosphaeridia spp. and some changes in the palynomorph proportions just before the significant lithological change near the lower/upper Maastrichtian. This signal may either be primary and record an environmental change, or taphonomic. Nevertheless, environmental interpretation of the upper Maastrichtian palynological assemblage seems to be more consistent with the late Maastrichtian marine regression, and in consequence, a reduction of the distance from the nearby land. Such conditions may have caused transport of leiosphaerids from shallower water sites.

Palynofloral diversity and palaeoenvironments of early Eocene Akri lignite succession, Kutch Basin, western India

This study presents palynological analysis of lignite-bearing succession of Akri lignite mine, Kutch, Gujarat, and discussed the implications of the recovered palynomorphs for age, palaeovegetation and palaeoenvironments. A diverse palynological assemblage consisting of algal and fungal remains, pteridophytic spores, angiosperm pollen and dinoflagellate cysts has been recorded. The lower part of the succession (samples 1–5) is dominated by marine dinoflagellate cysts along with palm pollen belonging to family Arecaceae. The upper part of the succession (samples 6–8, 11) is dominated by terrestrial palynomorphs attributed to megathermal families (Bombacaceae, Ctenolophonaceae, Dipterocarpaceae, Meliaceae) followed by mangrove and back-mangrove elements. An early Ypresian age is inferred for the Akri lignite deposit, whereas a middle Ypresian–early Lutetian age is assigned to the post-lignite succession based on the age-diagnostic dinoflagellate cysts and spore-pollen assemblage. Furthermore, based on the distribution of marine and terrestrial palynomorphs, two palynological assemblages (A and B) have been recognised that are apparently controlled by changing depositional environment. The overall palynological assemblage points to a dense tropical rainforest that thrived in the vicinity of the depositional basin under high precipitation regime of warm and humid climate. The peat accumulation took place in a near-shore coastal swamp which was interrupted by fluctuating marine influences, followed by increased siliciclastic influx in a low-salinity coastal swamp dominated by mangroves. Moreover, the palynological comparison suggests that widespread lignite-bearing successions in the western Indian region are in part coeval and belong to the early Eocene (Ypresian) age.

Stratigraphic revision of the El Imperial Formation (Pennsylvanian-Cisuralian), in its type locality, San Rafael Basin(Mendoza), Argentina

The El Imperial Formation (San Rafael Basin) shows a complete record of the late Carboniferous - early Permian stratigraphy in western basins of Argentina. The sedimentological and stratigraphic analysis in the type locality allowed recognizing eight facies associations. Facies association A includes diamictites and conglomerates related to the Late Paleozoic glacial event, facies B composed of shales and fine-grained sandstones, was formed during the postglacial transgression while facies C represents sandy littoral bars, that pass upward to shales and mudstones of the facies association D. The conglomerates and sandstones of the facies association E entirely correspond to fluvial sedimentation, followed by a new transgressive event represented in fine-grained sandstones and shales of the facies F. The last transgression is recorded in shales, mudstones and very fine-grained sandstones belonging to the facies G, which are covered by sandstones and conglomerates corresponding to multi-channel fluvial systems.From these facies associations, 33 palynofloras divided into three palynological associations were obtained. The palynological assemblages that characterized the basal section contain abundant trilete spores and monosaccate pollen grains, with a progressive increase of taeniate pollen towards the top of the unit. The presence of scolecodonts characterizes palynofloras from transitional to marine environments. The composition of the palynofloras allows correlations with the current biostratigraphic scheme of the center-west of Argentina. The presence of the Biozone Raistrickia densa- Convolutispora muriornata in the lower and middle part of the El Imperial Formation, together with Pakhapites fusus-Vittatina subsaccata Biozone in the upper part, allows us to refer the palynofloras to the late Serpukhovian/early Cisuralian.

Vegetational composition of the Upper Cretaceous vertebrate site of Chera (Valencia, Spain) and its significance in mosaic vegetation from southwestern Europe

A palynological study of the Upper Cretaceous vertebrate site of Chera (Valencia, Spain) has been carried out. The occurrence of diversified Normapolles including various species of Vancampopollenites, Papillopollis and Pseudoromeinipollenites suggest a late Campanian–?early Maachtrichtian age. The palynological assemblages suggest an azonal vegetation involving peat-mosses, sedges and palms colonizing wetlands with ephemeral or semi-permanent pools and lakes. The abundant and diverse Normapolles reflect the regional presence of woodlands or other open vegetation communities with prominent Fagales. The pollen and spore associations of Chera and the contemporary palaeobotanical data from SW Europe are indicative of the co-existence of numerous, structurally different and taxonomically individualized plant communities. The suggested palaeofloral heterogeneity is compatible with the current palaeogeographical reconstructions of SW Europe and probably enhance the appearance of the highly diverse fauna with insular characteristics of the latest Cretaceous.

First palynological results of accessorial elements from the Langhian Schaßbach clay pit, Lavanttal Basin (Austria) – LM and SEM investigations of Cornales and Ericales

Preliminary results of the palynoflora from the Schaßbach clay pit comprise accessorial floral elements of three Cornales and five Ericales pollen taxa that have modern living equivalents from different continents. The eight taxa are relatively rare in the palynological assemblages and are affiliated with the genera Nyssa, Mastixia, Erica, Vitellariopsis, Rehderodendron and Polyspora. Nyssa sp. resembles closely the deciduous Nyssa sylvatica of temperate America, the two Erica spp. resemble the south European tree heathers Erica arborea and Erica lusitanica, and Vitellariopsis sp. looks like evergreen Vitellariopsis marginata from subtropical southern Africa. The living equivalents of Mastixia spp., Rehderodendron sp. and Polyspora sp. are evergreen taxa from subtropical and tropical Asia.

A new palynological assemblage (Carboniferous) from the Chacoparaná Basin, Western Gondwana, and revision of the biostratigraphic scheme

A new palynozone for the upper Serpukhovian–Bashkirian (uppermost Mississippian–lower Pennsylvanian) strata of the Chacoparaná Basin (Argentina) is formally proposed based on palynological assemblages from the Santiago Temple YCF.CO1, YCF.CO2 and YCF.CO3 boreholes, drilled in Córdoba province. Thirty samples were analyzed and 222 palynomorph species identified. The Anapiculatisporites concinnus (Ac) Assemblage Zone is present only in the Santiago Temple boreholes and is divided into two subzones (lower and upper). The Ac Assemblage Zone has been identified in the lower part of the Ordóñez Formation, which is characterized by the presence of diamictites that would have been deposited in glaciolacustrine and glaciomarine environments. The Ac Assemblage Zone is correlated with subzones A and B of the Raistrickia densa–Convolutispora muriornata Zone defined in the western basins of Argentina. The known zones in the Chacoparaná Basin succession are redefined based on a review of borehole information, and the new zone is incorporated. Palynostratigraphically, the basin is divided into the Anapiculatisporites concinnus Assemblage Zone (upper Serpukhovian–lower Bashkirian), Potonieisporites–Lundbladispora Interval Zone (late Bashkirian–Gzhelian), Cristatisporites Interval Zone (late Gzhelian–early Kungurian) and Striatites (Kungurian–early Roadian) Assemblage Zone.

Dinoflagellate cysts and Foraminifera of the Upper Jurassic Lopsiya River sections, Nether-Polar Urals, NW Western Siberia (Russia)

The Upper Jurassic Lopsiya River sections (Nether-Polar Urals) represent the most complete stratigraphical marine sequence throughout Russia. It is characterized by a continuous succession of Kimmeridgian to Lower Volgian deposits and is defined by rich faunal associations including ammonites, belemnites, and bivalves. The Lopsiya River sections were previously studied in detail with palaeontological, lithological, and litho-geochemical purposes. Furthermore, assemblages rich in palynomorphs and foraminifers were found in the currently studied successions of the Lopsiya River sections. It results the establishment of the uppermost Oxfordian to Lower Volgian foraminiferal zones, as well as the Kimmeridgian dinoflagellate cyst zones and palynological assemblage. Then, the Upper Jurassic dinoflagellate cyst and foraminiferal biostratigraphical zonations have been calibrated against the ammonite zones. Finally, current results on the Lopsiya River sections have been compared with biostratigraphic data of the Kimmeridgian dinoflagellate cyst assemblages from northwestern Europe, Russian Platform, and Arctic Siberia. The studied foraminiferal and dinoflagellate cyst assemblages of the Upper Jurassic successions of the Lopsiya River sections hold high potential of correlations, especially for the Kimmeridgian strata.

Dinoflagellate cyst evidence for the age, palaeoenvironment and paleoclimate of a new Cretaceous–Paleogene (K/Pg) boundary section at the Bou Angueur syncline, Middle Atlas, Morocco

In this paper, we present results of a palynological analysis of the phosphate succession from the northern flank of the Bou Angueur syncline in the Middle Atlas (central Morocco). The studied interval yielded a well-preserved and diverse palynological content, dominated by dinoflagellate cysts (dinocysts), allowing a detailed taxonomic study of dinocyst and a new biostratigraphic dating of the section. The studied section is assigned to the upper Maastrichtian–Danian interval. A new, relatively complete K/Pg boundary transition was recognized. The succession at the Bou Angueur syncline was compared to Tethyan K/Pg boundary sections, such as the K/Pg boundary Global Stratotype Section and Point (GSSP) at El Kef (NW Tunisia) and Ouled Hadou section (NE Morocco). The dinocyst marker events used for the identification of the late Maastrichtian include the first occurrences of Cordosphaeridium inodes subsp. inodes, Deflandrea galeata and Glaphyrocysta perforata and those used for the early Danian include the first occurrences of Carpatella cornuta, Cassidium fragile, Danea californica, Lanternosphaeridium reinhardtii and Senoniasphaera inornata.The organic-walled dinocyst-producing dinoflagellates did not undergo the K/Pg mass extinction resulting from a large meteoritic impact. They enable us to interpret the environmental and climatic changes in the earliest Danian, while calcareous microfossils could not, since they are partially or completely extinct. We thus describe seven palynological assemblages, reflecting paleoenvironmental and paleoclimatic changes, inferred from changes in relevant ecological parameters, including changes in the relative abundance of selected dinocyst groups, often used as paleoenvironmental indicators. An inner to middle neritic marine environments alternated with several short phases of more offshore conditions is deduced for the late Maastrichtian and earliest Danian and an open outer neritic marine environment during a transgressive regime in the latest Danian. Several dinocyst events were recognized in the studied interval, among which remarkable blooms of tropical warm-water and high-latitude cold-water dinocyst taxa are interpreted herein as ecological responses, related to global climatic changes, including a global warming episode during the late Maastrichtian and the well-known brief global cooling following the K/Pg boundary Chicxulub impact.