Monosaccate Pollen Grains Research Articles

Paleontology of Pennsylvanian transgressive deposits in northwestern Precordillera, San Juan province, Argentina

In central-western Argentina, sedimentological and paleontological studies have identified changes in sea levels during the Pennsylvanian period. After the late Serpukhovian-early Bashkirian postglacial transgression, two main flooding events occurred. Among these, Pennsylvanian transgressions 1 and 2 are considered the most significant. New palynological samples recovered from the T1 transgression in Puesto Volcán, western Precordillera (San Juan province) reveal the presence of the Raistrickia densa-Convolutispora muriornata (DM) Biozone. The palynofloras are characterized by the recognition of Ahrensisporites cristatus, Lundbladispora spp., Raistrickia densa, Spelaeotriletes ybertii, and monosaccate pollen grains. The composition of the assemblages includes some taeniate pollen grains suggesting their assignment to the Subzone B. A new orthoconic cephalopod was also identified in the same stratigraphic interval, which adds to the invertebrate faunal record and confirms the marine environment. Imprints of foliage of Fedekurtzia argentina complete the paleofloristic assemblage. A late Bashkirian-earliest Moscovian age is suggested according to the well constrained radiometric control of the palynostratigraphy in the region.

Palynology and palynofacies of the Permian Paso Aguiar and Yaguarí formations (Paraná Basin, Uruguay): Paleoclimatic, paleoenvironmental, and biostratigraphic implications

The palynological information of the Paso Aguiar Formation (Paraná Basin, Uruguay) is scarce, and the overlying Yaguarí Formation has been hitherto considered as barren. In this study, the palynology and palynofacies of 17 samples recovered from borehole DINAMIGE 943 “Estancia El Águila”, drilled in the Cerro Largo Department (northeastern Uruguay), are analyzed. Palynological assemblages are dominated by striate bisaccate pollen grains, mainly those assigned to the genera Staurosaccites and Lueckisporites, and subordinated apiculate monolete and cingulizonate-cavate spores, essentially represented by Thymospora and Lundbladispora, Gondisporites, and Spelaeotriletes, respectively. The assemblages also include non-taeniate bisaccate and plicate-colpate pollen grains, laevigate and apiculate trilete spores, and algae. Moreover, laevigate monolete spores, non-taeniate and taeniate monosaccate pollen grains, and acritarchs are present in low quantities. The diverse palynoassemblages constitute evidence of a source palaeoflora primarily composed of gymnosperms, with important contributions from glossopterids and conifers. This is complemented by sub-dominant ferns and lycophytes, implying seasonally warmer and humid climates. The palynofacies analysis suggests marine depositional environments with terrestrial inputs related to fluvio-deltaic discharges. Proximal-distal variations are inferred for the lower and middle levels of the Paso Aguiar Formation, while high-energy proximal marine settings with variable redox conditions are deduced for the upper Paso Aguiar Formation and the lower Yaguarí Formation. The abundance of spores recorded is noteworthy, particularly when considering the environmental interpretations for these units. However, the influence of differences in preservation among palynomorphs cannot be entirely ruled out. The assemblages are assigned to the Striatoabieites anaverrucosus-Staurosaccites cordubensis Zone of the Paraná Basin in Uruguay. Nevertheless, obtaining additional data from the studied geological units is crucial to enhance and fine-tune the existing palynostratigraphic framework. Considering the radiometric ages available for the Paraná Basin, along with the ages proposed for comparable biozones in the region and assemblages from correlative units in Brazil, a late Cisuralian–late Guadalupian (Kungurian to Capitanian) age is suggested for the studied section.

Paleogeographic records of glacial and terminal glacial palynozones related to the Late Paleozoic Ice Age in the Brazilian portion of the Paraná Basin, Western Gondwana

Among the four palynozones established for the Pennsylvanian–Permian sedimentary succession of the Paraná Basin, two are related to the glacial (AcZ: Ahrensisporites cristatus and CmZ: Crucisaccites monoletus zones) and one is related to the following terminal glacial phase (VcZ: Vittatina costabilis Zone) in this portion of Gondwana. The AcZ and the CmZ are typically recognized within the basal and middle portions of the Itararé Group and the Aquidauana Formation, while the VcZ corresponds to the upper portions of both units. In this paper we present a palynostratigraphic analysis of all occurrences of these palynozones from 66 boreholes and 29 outcrops. Two paleogeographic maps are depicted showing the distribution of all sections where the palyonozones related to glacial and terminal glacial sections occur within the Itararé Group and the Aquidauana Formation. Glacial palynozones (AcZ and CmZ) are recognized from outcrops and boreholes from Santa Catarina, Paraná, São Paulo, Mato Grosso do Sul, Mato Grosso and Goiás states, encompassing the thickest portion of the Itararé Group and the Aquidauana Formation. The terminal glacial palynozone (VcZ) was recognized from several boreholes and outcrops, well distributed throughout the basin, from the Rio Grande do Sul, Santa Catarina, Paraná, São Paulo and Mato Grosso do Sul states. Reworked palynomorphs from Devonian and Mississippian strata found together with indigenous species in assemblages assigned to the glacial palynozones (AcZ and CmZ) are used herein as a tool for interpretation of the source area and as indicators of transport direction. As observed elsewhere in Gondwana, palynozones related to the glacial and terminal glacial phases present dominance of spores and monosaccate pollen grains, whereas those linked to the latter phase record the income and the quantitative increase of certain species indicative of progressive climate amelioration. Further sedimentary and stratigraphical aspects are also discussed.

New age, stratigraphic and paleoenvironmental interpretation of the Loma de los Piojos Formation (San Juan Province, Argentina) based on new palynologic and stratigraphic information

A physical stratigraphic study of the Loma de los Piojos Formation (LPF) and related units at the homonymous locality (5 km north of Jachal city, San Juan Province, Argentina) was carried out. The first palynologic result is presented herein from the shale beds of the Loma de los Piojos Formation, just below the deposits bearing floral remains of the Frenguellia eximia–Nothorhacopteris kellaybelenensis–Cordaicarpus cesarii (FNC) informal zone of Balseiro et al. (Serpukhovian sensu lato). The Loma de los Piojos does not have an exposed base, and the Guandacol Formation (late Serpukhovian–early Pennsylvanian) overlies it. Also, the field work analysis allowed the association of LPF shales with the last depositional sequence of the recently defined and underlying Don Buenaventura Formation, of late Mississippian–earliest Pennsylvanian age. The four fertile samples obtained from the shale beds of the LPF yielded 45 species of terrestrial plants. Monosaccate pollen grains (Cannanoropollis janakii, Cannanoropollis mehtae, Circumplicatipollis plicatus, Crucisaccites monoletus) represent the Cordaitalean and Coniferalean that varied in their frequency c. 25 % in the lower two samples to 34 % and 7 % in the other two. Spore species of lycophytes dominate in all samples (ca. 50–80 %) along with other spores that appeared in the late Serpukhovian–Bashkirian subzone A of the Raistrickia densa–Convolutispora muriornata Palynozone (DMZ). However, in the lowest sample the key spore Spelaeotriletes ybertii and a well-preserved specimen of the striate bisaccate pollen Illinites unicus allowed the correlation with the late Bashkirian–Moscovian Subzone B of DMZ. Therefore, the informal floral zone Frenguellia eximia–Nothorhacopteris kellaybelenensis–Cordaicarpus cesarii is here reallocated to the Nothorhacopteris–Botrychiopsis–Ginkgophyllum (NBG) Zone, which is relevant in the global context of the evolution of the plant groups involved. This dark shale section would correspond to a warmer interval during which the maximum flooding zone was dated c. 320 Ma locally at the Huaco section (also close to Jachal city), also documented across the Paganzo Basin up to the Paraná Basin in Brazil. The three Late Paleozoic mentioned units were deposited within the largest incised valley complex of this region based on the amount of preserved depositional sequences (7), thickness (>1 km), and time span (from Late Mississippian to lower Pennsylvanian). This complex stratigraphic succession formed within a large paleovalley probably acted as a trunk drainage system connecting depositional areas from the continental interior with coastal areas of the Gondwanan continental western margin.

Palaeoclimate, Palaeoecology and Palaeovegetation in and around Nandira Colliery, Talcher Basin, Odisha, India during Early Permian: Inferences from Typical Karharbari Palynofloral and Palynofacies Analysis

Abstract Palynofloral study along with palynofacies analysis has been undertaken in Nandira colliery, Talcher basin, Odisha, India. Recovered palynoassemblage is characterized by the dominance of monosaccate pollen grains viz., Parasaccites spp. (25%), Plicatipollenites spp. (5%), Potonieisporites sp. (1%) and Diavarisaccus lelei (1%) along with nonstriate bisaccate Scheuringipollenites maximus (35%). The recovered palynoflora shows its affinity towards the Upper Karharbari palynoflora of the early Artinskian age. The organic matter studied from the palynofacies investigation includes palynomorphs (SP), structured phytoclasts/ translucent phytoclasts (ST), opaque phytoclasts/ charcoal (CH), degraded organic matter (DOM), and amorphous organic matter (AOM). The carbonaceous shale (Sample Na) is dominated by SP (34.67%) and sub-dominated by ST (22%) along with CH (13.34%), DOM (19%), and AOM (11%). Coal samples (Nb to Ne) are completely devoid of palynomorphs. They are mainly dominated by CH (24.87-62.34%) and ST (20.20-73.38%) with presence of DOM (0.7-8.7%) and AOM (0.4-8.7%). Deposition of the sediments in a lower carbonaceous shale bed (Na) might have occurred in a dysoxic forest swamp in low-energy settings. The coal beds (Nb to Ne) have been deposited in the oxidized swamps in the proximal setting. The predominant occurrence of the opaque phytoclasts associated with the coal sediments may indicate a regular occurrence of palaeofires during the Artinskian.

First record of late Carboniferous palynoassemblage from Ganmachidam Formation, Spiti Valley: Implications for age assessment and extent of Glossopterid elements in the Tethyan realm

The present work elucidates miofloral records from the Ganmachidam Formation (late Carboniferous–earliest Permian) of Spiti Valley, Tethyan Himalaya. The Ganmachidam Formation was hitherto considered as unfossiliferous, both for the faunal as well as floral records, and has been subjected to contentious age assessment. The present study has been carried out to find out the microfloral remains, assess the palynostratigraphic status, and the age of the Ganmachidam Formation. From the splintery shale sequence, a rich assemblage of palynomorphs has been recovered, having a dominance of monosaccate pollen grains, namely Parasaccites (Cannanoropollis), Crucisaccites, Divarisaccus, Densipollenites, Maculatasporites, followed by diverse bisaccate pollen grains, namely Scheuringipollenites, Crescentipollenites, Faunipollenites (Protohaploxypinus), Lunatisporites, Striatopodocarpites, Striatites, Rhizomaspora, Primuspollenites, and the spores Callumispora (Punctatisporites) and Calamospora in addition to woody fragments and fungal spores. Three palynoassemblages are identified. The recovered palynocomposition is corroborated with known records of palynomorphs from the Tethyan realm of India and from the late Carboniferous–Early Permian records of contemporaneous sequences across the globe. The composition of these palynoassemblages shows close correlation with the Crucisaccites monoletus Zone and Vittatina costabilis Interval Zone in the northeastern area of the Paraná Basin, Brazil, and lower Barakar palynozone (Scheuringipollenites barakarensis Assemblage Zone) of Peninsular India which indicates the studied section of the Ganmachidam Formation is late Pennsylvanian to early Permian in age. Moreover, occurrences of palynomorphs from the Carboniferous sequences having a glossopterid affinity further strengthen the idea that glossopterids might have originated in Carboniferous time.

Upper Pennsylvanian Age of the Lower Talchir Formation in the Wardha Basin, Central India, Based on Guide Palynomorphs Present in Radiometrically-Dated Palynozonations in South America, Africa, and Australia

The age of the Talchir Formation corresponding to the lower part of the Gondwana (Permo–Carboniferous) Sequence in India is revised in the light of palynostratigraphic data associated with radiometric dating generated in Gondwana. New data was generated from seven samples of the Talchir Formation obtained from Well 131, located in the Penganga area of Wardha Valley Coalfield (Maharashtra State, central India). Two assemblages were demarcated based on the stratigraphic distribution of 63 species of spores (23 taxa), pollen grains (35 taxa), and phytoplankton. Palynoassociation I recognized in the two basal samples yielded few Punctatisporites spores and monosaccate pollen grains. Palynoassociation II is demarcated in the overlying three samples characterized by spores and pollen grains that are more diversified and abundant than in the other two samples. Several taxa (Concavissimisporites grumulus, Converrucosisporites confluens, Cyclogranisporites gondwanensis, Verrucosisporites andersonii, Latusipollenites quadrisaccatus, Marsupipollenites striatus, Pakhapites fusus, Striatoabieites multistriatus, Vittatina subsaccata, Vittatina vittifera) are shared with palynozones radiometrically constrained to the latest Pennsylvanian–early Cisuralian in Argentina, Brazil, Africa, and Australia. Therefore, we propose a Kasimovian to Ghezelian–Asselian age for the palynoassociations I and II of the Talchir Formation and a correlation with the Potonieisporites neglectus and Plicatipollenites gondwanensis Zones of Tiwari & Tripathi, respectively. This approach significantly improves the stratigraphic correlations of the Indian palynozones in Gondwana.

The Vittatina costabilis Zone revisited: New characterization and implications on the Pennsylvanian-Permian icehouse-to-greenhouse turnover in the Paraná Basin, Western Gondwana

The accuracy of the radiometric ages for the Pennsylvanian-Permian section of the Paraná Basin has been progressively increased in the past two decades, allowing a better chronostratigraphic calibration to the related biozones. Most of these new ages are from levels containing spore-pollen associations assigned to the Vittatina costabilis Zone (VcZ), which is revised in detail herein. Unlike previous biostratigraphic proposals, we verified that VcZ is positioned between the Gzhelian and the Artinskian, documenting the Pennsylvanian-Permian transition. A new palynological characterization is proposed for this palynozone, including (i) changes in the definition of its lower and upper limits and (ii) the invalidation of its subzones. Although spores and monosaccate pollen grains are dominant in the VcZ, gymnospermic taeniate bisaccate and polyplicate pollen grains become progressively more abundant up section, representing new plant groups mainly linked to gymnosperms and allied groups. The VcZ documents the first appearance of certain Gondwana taxa of stratigraphic value, such as Converrucosisporites confluens and several species of Vittatina. The stratigraphical distribution of the VcZ is redefined based on previous and unpublished data. In general, the zone is well developed along the basin, but it is better represented between Santa Catarina and São Paulo States. No palynostratigraphic changes were consistently observed throughout the palynozone, which is recognized into two lithostratigraphical units of distinct paleoclimatic nature: the upper Itararé Group and the Rio Bonito Formation. Considering that earliest appearance of the Glossopteris in Paraná Basin is recorded within the upper Itararé Group from levels bearing palynological associations assigned to the VcZ, a Pennsylvanian age is evidenced for this plant group, which only became dominant across the Gondwana areas in Permian times.

Palaeoenvironmental Interpretation of the Upper Triassic Baluti Formation in two selected sections at Amediya District, Kurdistan Region- Iraq: Insights from Palynofacies Study

Palynofacies analysis was carried out on 28 outcrop samples from the Upper Triassic Baluti Formation from Zewa and Sararu Sections in south and northwestern of Amediya District respectively, Kurdistan Region- Iraq. Based on the studied palynofacies, both sections are quite different in terms of depositional environment. Four types of palynofacies were recognized as following: the palynofacies type IV (Pl.1) is observed in the lower, middle and upper portions of upper part of Zewa Section in which, is characterized by high amount of phytoclasts, medium percentage of amorphous organic matter (AOM) and palynomorphs. This facies is referred to a depositional area that is located relatively nearshore with an arid hinterland, the palynofacies type V (Pl.2) was observed in lowermost and middle portions of upper part of Zewa Section, which is characterized by high domination of palynomorphs (mainly bisaccates and monosaccate pollen grains) and a less amount of phytoclasts and AOM. This facies indicates the domination of shallow marine to continent environment. The palynofacies type VI (Pl.3) was observed in middle and upper portions of upper part of the Zewa Section and lower and upper parts of the Sararu Section. This facies showed less amount or absence of palynomorphs, and relatively high amount of AOM and phytoclasts. In addition to this, a remarkable percentage of dinoflagellate cysts in Sararu Section has been found in this facies. This facies indicates proximal suboxic-anoxic shelf, and palynofacies type IX (Pl.4) was observed in middle to upper part of Sararu Section and characterized by less amount or absence of palynomorphs with high amounts of AOM and phytoclasts, which represents a deep environment of deposition.

Timing of the Late Palaeozoic glaciation in western Gondwana: New ages and correlations from Paganzo and Paraná basins

During the Late Palaeozoic, the Gondwana supercontinent formed an extensive Southern Hemisphere landmass that was affected by multiple glacial episodes, known collectively as the Late Palaeozoic Ice Age (LPIA). This resulted in the deposition of glacial, periglacial and deglacial sediments over much of the supercontinent. The Mississippian to early Pennsylvanian phase of glaciation is widely represented along the western margin of Gondwana. This constitutes one of the largest glaciations of the Phanerozoic in terms of its recorded extent and the widespread erosional hiatus it produced in the stratigraphic record. It was this mid Carboniferous glaciation, recorded in the Paganzo Basin of NW Argentina, that carved most of the paleovalleys and paleofjords present there. We report new U-Pb zircon ages from a single glacial succession (Guandacol Formation) of 326 ± 3 Ma and 320 ± 5 Ma, that in comparison with neighbouring dated sequences allow for the first time a reliable estimate of the timing and duration of glacial cycles. Palynological studies of these glacial-deglacial events yielded palynoassemblages of the MQ (Late Visean) and DMa (Sepukhovian-Bashkirian) Palynozones. The Carboniferous glacially-related strata and glacial cycles of the Paganzo Basin are compared here with equivalent units of the Paraná Basin of SE Brazil, suggesting a similar climate record for most of western Gondwana. We propose a new correlation between these two basins. The new U-Pb zircon ages reported here indicate that a regional glacial peak occurred almost coincident with the Mississippian-Pennsylvanian boundary, suggesting that the ensuing postglacial transgression is the best regional marker to differentiate the Mississippian and Pennsylvanian as it forms an identifiable interbasinal horizon. The biostratigraphic and chronostratigraphic comparison with other LPIA successions from South America reinforces that the First Appearance Datum of monosaccate pollen grains occurs in the late Serpukhovian. Their correlation confirms that similar climate conditions prevailed across most of western Gondwana during this phase of the LPIA.

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.

Palynomorphs from the Barakar Formation of Dhanpuri Open Cast Mine, Sohagpur Coalfield, Madhya Pradesh, India

Well preserved palynomorphs from the Barakar Formation of Dhanpuri Open Cast Mine, Sohagpur Coalfield, Shahdol District, Madhya Pradesh are reported for the first time. The palynomorphs include megaspores and spores/pollen grains. Dispersed megaspores are represented by 6 genera and 13 species comprising Banksisporites indicus, B. utkalensis, Banksisporites sp., Barakarella shuklae, Barakarella sp., Biharisporites sp. Bokarosporites rotundus, Bokarosporites sp., Jhariatriletes baculosus, Jhariatriletes sp., Talchirella flavata, T. trivedii and Talchirella sp. The microspore assemblage shows dominance of monosaccate pollen grains namely Parasaccites obscures, P. korbaensis and Plicatipollenites indicus, along with sub–dominance of non–striate bisaccate taxa Scheuringipollenites barakarensis and S. maximus. Other palynomorphs include trilete Callumispora barakarensis, striate bisaccate pollen grains Faunipollenites sp. and Striatopodocarpites multistriatus, non striate bisaccate genera Ibisporites diplosaccus and Platysaccus ovatus, along with Tiwariasporis gondwanensis and Vitreisporites sp.

Palynostratigraphy and correlation of the coal bearing Gondwana sediments in the Kothagudem sub basin of the Godavari Graben, South India

The present investigation deals with the palynology of five sections from the Kothagudem sub–basin of the Godavari Graben, India to unravel the biostratigraphy and palaeovegetation. The palynological analysis in the five sections of Rampur, Hemchandrapuram and Kothagudem areas revealed the presence of Karharbari (Palynozone–I), lower Barakar (Palynozone–II) and Raniganj (Palynozone–III) equivalent palynofloras in lithologically designated Barakar Formation. Palynozone–I is dominated by cordaitalean radial monosaccate pollen grains (Parasaccites spp., Plicatipollenites spp.) and trilete spores (Callumispora spp.) which represent colder climatic conditions. Palynozone–II is chiefly dominated by non–striate bisaccate (Scheuringipollenites spp. and Ibisporites spp.) and striate bisaccate (Faunipollenites spp., Striatopodocarpites spp.) grains of conifer and glossopterid origin indicating presence of peat–forming plants and conducive climatic condition for the coal formation. Palynozone–III is mainly dominated by striate bisaccate pollen grains of glossopterid origin along with conifer (Faunipollenites spp., Striatopodocarpites spp., Crescentipollenites spp.) and peltasperm (Falcisporites spp., Chordasporites spp.) pollen grains representing hot and humid conditions. Palynozone–III is characterized by the dominance of striate bisaccate taxa along with stratigraphically significant palynomorphs (Corisaccites sp., Guttulapollenites sp., Lunatisporites sp., Chordasporites sp., Falcisporites sp., etc.). On the basis of palynofloral composition Palynozone–I, II and III have been assigned to the Sakmarian (upper Karharbari), Artinskian (lower Barakar) and Lopingian (Late Permian) age respectively.

Seasonally warmer and humid climates in a lower paleolatitude position of southern Brazil (Paraná Basin): new findings of the Lueckisporites virkkiae zone (late Cisuralian-Guadalupian) in the Serra do Rio do Rastro and neighboring localities

First palynological information from surface samples of the Serra Alta and Rio do Rasto formations (Passa Dois Group, Paraná Basin), exposed in the Serra do Rio do Rastro (White's Column) and Urubici regions in Santa Catarina State (Brazil) is presented. The Serra Alta Formation is transitionally deposited over the Irati Formation, which is constrained to the late Artinskian/Kungurian by different paleontological and radiometric data. Twelve productive samples (of forty) yielded fairly well preserved palynomorphs, dominated by striate and non striate bisaccate and asaccate pollen grains and subordinated trilete and monolete spores, monosaccate pollen grains and Botryococcus. Diagnostic species of the Lueckisporites virkkiae Zone (Artinskian-Guadalupian) in the Paraná Basin are recorded along with few species of Guadalupian-Lopingian age (e.g. Cladaitina veteadensis, Guttulapollenites hannonicus, Lophotriletes parryensis, Protohaploxypinus microcorpus, Staurosaccites quadrifidus, Weylandites cincinnatus). They support a Kungurian-?Roadian age for the Serra Alta, and a Capitanian (?Lopingian) age for the Rio do Rasto formations. Four samples from the Sete Quedas outcrop yielded scarce and poorly preserved specimens of Lueckisporites likely due to weathering. A statistic comparison among our assemblages and selected Permian palynozones and palynofloras from South America supports a closer correlation with the La Veteada Formation (Guadalupian-Lopingian) from western Argentina due to common occurrence of all the species, and with the Striatites Zone (late Artinskian-Kungurian) of the Chacoparaná Basin, and the I-S Zone Melo Formation in Uruguay. The botanical affinities of the palynomorphs from both assemblages indicate the presence of spores of hygro-mesophytic affinities along with meso-xerophyle pollen grains, which is in agreement with seasonally warmer and humid climates favored by a lower paleolatitude position. The presence of pyrite in some of the miospore exines in most the levels analysed suggest the marine influence in the depositional environment of the Serra Alta and lower Rio do Rasto formations in the southern region of Brazil.

Palynofloral associations before and after the Permian–Triassic mass extinction, Kap Stosch, East Greenland

The Permian–Triassic boundary (PTB) interval is known to document a major biodiversity crisis in the history of life. It is generally accepted that this crisis had a significant impact on marine invertebrates. The consequences for terrestrial ecosystems are still controversially discussed. Based on palynological analysis we present a high time resolution microfloral succession of the expanded Late Permian (Wuchiapingian)–Early Triassic (Dienerian) section from Kap Stosch, East Greenland. The quantitative distribution of palynomorphs (range charts and relative abundance data) allows for the differentiation of six distinct palynofloral associations. Ammonoids and conodonts provide independent age control for these assemblages. The Wuchiapingian association I, documented from the Ravnefjeld Formation, shows a typical Late Permian assemblage dominated by bisaccate and monosaccate pollen grains and Vittatina spp. It is separated from association II, present in the basal part of the Wordie Creek Formation, by an important hiatus. This association of Changhsingian or earliest Griesbachian age is characterised by the common occurrence of Ephedripites spp. and reduced abundance and diversity of Vittatina spp. Association III, dated as Griesbachian by the presence of ammonoids, is marked by high relative abundances of taeniate bisaccate pollen grains and high spore diversity. A distinct floral break occurs between the gymnosperm dominated Permian and Griesbachian floras and the lycopsid spore dominated Dienerian associations IV–VI. Ammonoid occurrences verify a Dienerian age for the latter associations. Association V is marked by the absence of non-taeniate bisaccate, striate monosaccate pollen grains, and Vittatina spp. Aratrisporites spp. a typical Triassic lycopsid spore occur consistently from this level onwards. Association VI is characterised by highest lycopsid spore abundances. Cluster analysis demonstrates that Griesbachian assemblages (associations II?–III) are similar to Permian ones and clearly differ from Dienerian assemblages confirming a major floral turn-over near the Griesbachian–Dienerian boundary. In contrast to the commonly advocated idea of a profound effect of the PTB crisis on terrestrial ecosystem, the present data set shows no major effect of the PTB event on floral diversity. Strikingly, considering species numbers alone, the major floral event at the Griesbachian–Dienerian boundary is also indistinct, but sticks out from abundance data, emphasising the necessity to consider both species ranges and abundances data to characterise terrestrial ecosystem dynamics in critical time intervals. Generally we note a gradual disappearance of Permian floral elements such as Vittatina spp., Weylandites spp. or Florinites spp. and a gradual appearance and diversification of typical Triassic spores such Aratrisporites spp. and Densoisporites nejburgii.

Palinomorfos e associações de fácies da Formação Lagoa Azul (Grupo Itararé, Pennsilvaniano da Bacia do Paraná) no sudeste do Estado do Paraná, Brasil

No sudeste do Estado do Paraná, o Grupo Itararé assenta-se por meio de discordância angular sobre o substrato pré-glacial, que é composto de unidades precambrianas a devonianas, cada vez mais velhas para o sudeste. Devido a esta configuração estratigráfica, tem-se interpretado que os estratos aflorantes na região de Porto Amazonas representam os níveis mais inferiores do Grupo Itararé, enquanto aqueles da região de Campo do Tenente, localizados mais ao sul da área, representam seções mais jovens. Este artigo apresenta o resultado da análise palinológica e faciológica realizada em sete afloramentos da porção basal do Grupo Itararé (Formação Lagoa Azul), nas regiões de Porto Amazonas, Lapa e Campo do Tenente, visando ao posicionamento palinoestratigráfico. Nove fácies sedimentares foram identificadas compondo, na maior parte, depósitos de transporte de massa e turbiditos, acumulados em ambiente marinho relativamente profundo sob influência glacial. Associações palinológicas foram registradas em todas as três regiões, incluindo escassos elementos indígenas, compreendendo esporos e grãos de pólen monossacados, com grau de preservação variado. As características palinológicas gerais das associações e a presença de determinadas espécies de esporos e grãos de pólen sugerem posicionamento na Zona Ahrensisporites cristatus, correspondente à porção inferior do Grupo Itararé (Formação Lagoa Azul), de idade pennsilvaniana (Neobashkiriano a Kasimoviano). Os resultados obtidos confirmam a ocorrência de estratos glaciais da parte inferior do Grupo Itararé na faixa de afloramentos. Além disso, demonstram a importância do estudo dos processos de retrabalhamento e ressedimentação de palinofósseis pré-pennsilvanianos.

Integrated U-Pb zircon and palynological/palaeofloristic age determinations of a Bashkirian palaeofjord fill, Quebrada Grande (Western Argentina)

This work presents a new age framework for the main Bashkirian glacio-eustatic transgression in Argentina, including the first absolute age for the Jejenes Formation, San Juan Province, based on radiometric dating of a crystal-rich tuff, supported by palynological and palaeofloristic studies, and presented within a revised palaeogeographic setting. The Jejenes Formation represents the glacial to postglacial fill of the Quebrada Grande palaeofjord carved in the Eastern Precordillera. The succession has been subdivided into five stages, the youngest of which suggests a previously unrecognised glacial event for this locality. Six productive levels for palynology were found within proglacial strata, and in the base and top of the succeeding interglacial stage. Palynoassemblages are characterized by poorly preserved trilete spores and monosaccate pollen grains along with a large amount of terrestrial phytoclasts. Main species indicating the Raistrickia densa-Convolutispora muriornata SubZone (DMa SZ) are Vallatisporites ciliaris, Cristatisporites rollerii, C. stellatus, C. chacoparanensis, C. inconstans and monosaccates such as Circumplicatipollis plicatus. This DMa SZ is estimated as Serpukhovian/Bashkirian and characterizes the glacial-related Guandacol Formation and equivalents units of the western Paganzo Basin. A tuffaceous level in the proglacial unit, bearing platyspermic seeds, plant remains and palynomorphs, yielded first-cycle volcanic zircons that were analysed by SHRIMP. An absolute age of 321.3 ± 5.3 Ma confirms a Bashkirian age for the main postglacial transgression in the Paganzo Basin, and offers a novel calibration for the palynoassemblages of DMa SZ that occurs elsewhere in Western Argentina.

A palynostratigraphic study of the Umrer Coalfield of Wardha Basin, Maharashtra State, Central India and its putative correlation with Indian and other Gondwanan areas

The present work details the results of the palynological studies carried out in the Umrer Coalfield of Wardha Basin of Maharashtra State, Central India. The coalfield covers an area of 4 sq. km and is characterized by three coal seams designated as bottom, middle and top seams with partings. Statistical analysis of the palynomorphs from these sediments have revealed the dominance of radial monosaccate pollen grains of the genus Parasaccites and subdominance of non-striate bisaccate genus Scheuringipollenites in association with other typical early Permian taxa viz. Crucisaccites, Callumispora, Caheniasaccites, Brevitriletes, Tiwariasporis and Primuspollenites. This association characterizes the palynoflora of the upper Karharbari Formation of India on the basis of which the Umrer Coalfield has been assigned an early Permian late Sakmarian to early Artinskian age. It is further authenticated by the presence of the species Crucisaccites monoletus significant of the Karharbari Formation. Age deductions have also been made by correlations with similar assemblages from different basins in India and early Permian palynoflora from other Gondwanan continents some of which have been associated with radiometrically dated sediments.

Palynofacies as a tool for high-resolution palaeoenvironmental and palaeoclimatic reconstruction of Gondwanan post-glacial coal deposits: No. 2 Coal Seam, Witbank Coalfield (South Africa)

The early Permian movement of Gondwana away from the South Pole caused a major climatic change across the continent. The shift from a post-glacial Carboniferous flora to a temperate Permian flora is represented in the palynological record. Using palynofacies analysis, this climate transition can be studied at a high resolution, and the palaeoenvironment can be interpreted on a local scale. Core samples were studied from four localities of the Artinskian/Kungurian-aged No. 2 Coal Seam of the Witbank Coalfield. At some localities, the No. 2 Coal Seam is split into an Upper Coal Seam and a Lower Coal Seam by an intraseam parting, and samples were collected from both horizons as well as the parting. All samples were studied with respect to palynomorph composition and phytoclast content. The results suggest a swamp-dominated environment in the Lower Coal Seam, a river-dominated environment in the parting, and an environment which fluctuated locally from a lake-dominated to swamp-dominated in the Upper Coal Seam due to increased input of glacial meltwater from the hinterlands. The vegetation switched from a fern- and conifer-dominated flora in the Lower Coal Seam to a more diverse Glossopteris-Gangamopteris flora in the Upper Coal Seam. Cordaites appears to be limited to valleys on the northern edge of the swamplands in the Lower Coal Seam. A decrease in monosaccate pollen grains and an increase in bisaccate pollen grains are apparent in all sample sets and interpreted to indicate a transition from a cold to a fluctuating cool-temperate climate. This climate signal is well documented in palynofacies of the coal seam and thus a powerful correlation tool for high-resolution basin-wide and Gondwanan correlation.

Biostratigraphy and paleoecology of an unusual palynological record from the Aquidauana Formation, Late Pennsylvanian of Paraná Basin.

The Aquidauana Formation is a Permo-Carboniferous sedimentary unit, widely stratigraphicaly distributed in the northwestern and northern portions of the Paraná Basin. However, little paleontological data is available from this formation, preventing accurate biostratigraphic and paleoecological interpretations. An abundant, diversified and well preserved assemblage of palynomorphs was recognized from sampling conducted in an outcrop section in Cipolândia District of Aquidauana Municipality, state of Mato Grosso do Sul, Brazil. A total of 35 indigenous palynomorph taxa was recognized, comprising 6 species of spores (related to 5 genera), 28 species of pollen grains (14 genera) and 1 species of chlorophycean algae. Monosaccate pollen grains are exceptionally dominant, representing 90.38% of the association, particularly constituted by species of the genera Cannanoropollis (30.41% of the total assemblage), Potonieisporites (28.14%) and Plicatipollenites (19.52%). This quantitative overrepresentation is not usual from Gondwana deposits, revealing a particular plant dominance of Cordaitales in the terrestrial flora. These results are interpreted as an upland ecology characterized by plants with a moisture-independent reproduction strategy, under a glacial climate influence. Certain species of pollen allow assignment of this assemblage to the Crucisaccites monoletus Zone (Late Pennsylvanian), which had been recognized only in the middle portion of the Itararé Group at the northeastern margin of the basin.