Triassic Palynoflora Research Articles

Age constraints of the Guttulapollenites hannonicus–Cladaitina veteadensis Biozone in Argentina reveal the first record of Early Triassic (Olenekian) palynofloras in Western Gondwana

The upper Palaeozoic basins of central-western Argentina include continuous fossiliferous successions spanning the Carboniferous-Permian interval. The palynostratigraphic biozones comprise Late Mississippian, Pennsylvanian and Cisuralian assemblages. Recently, new palynofloras of the La Veteada Formation were referred to the Lopingian (late Permian). However, they are characterized by spores and tetrads of Lundbladispora spp. and Densoisporites spp., pollen grains of Lunatisporites pellucidus, L. noviaulensis and Protohaploxypinus samoilovichii, and the alga Syndesmorion stellatum, that distinguish the post-Permian recovery floras worldwide. A new uranium-lead chemical abrasion-isotope dilution-thermal ionization mass spectrometry (U-Pb CA-ID-TIMS) age confirms the Olenekian age of this stratigraphic unit and allows the identification of the first Early Triassic palynofloras in this region of western Gondwana. Comparison and correlation with similar assemblages from the southern and northern hemispheres supports the Early Triassic turnover with an increase of lycopsid cavate spores associated with some diagnostic species of taeniate and non-taeniate bisaccate pollen.

Gondwana biostratigraphy and geology of West Bengal Basin, and its correlation with adjoining Gondwana basins of India and western Bangladesh

Integrated biostratigraphic and geological studies on the drilled exploratory boreholes of West Bengal Basin have revealed the presence of very thick distinctive Permo-Triassic Gondwana successions in the subsurface, and widely recognized across the basin below the latest Jurassic–Early Cretaceous Rajmahal Traps. Precise geological age of identified Gondwana lithounits of this basin is inferred on the basis of associated palynofloral assemblages along with their correlation with the adjoining Gondwana basins. In addition, two Gondwanic grabens are recognized below the pericratonic set-up whose presence in this basin, till now, are poorly understood. Detailed palynological studies on the Gondwana successions in the key boreholes of this basin enable recognition of 12 established palynological zones ranging from Early Permian (Asselian) to Middle Triassic (Ladinian). Lower Gondwana (Permian) palynofloras of this basin resemble earlier recorded palynofloras from the Talchir, Barakar and Raniganj formations of Indian Gondwana basins, suggesting the occurrence of well-developed above Lower Gondwana lithounits in this basin and the absence of Karharbari and Barren Measures formations which are marked by the non-depositional hiatuses. Upper Gondwana successions (Triassic) of the basin are represented by the Early and Middle Triassic palynofloras only that resemble Panchet and Supra-Panchet (Molangdighi Formation) palynofloral assemblages, and indicate the absence of Late Triassic succession of Upper Gondwana. Newly acquired geological and Bouguer anomaly data, and spatial distribution of Gondwana bearing boreholes across the basin suggest that the boreholes of CHK-A, GB-A, HRP-A, AMD-A, PLS-A and MNG-A fall in a well-defined NNE–SSW aligned graben, defined as the ‘Chandkuri–Palasi–Bogra Gondwanic Graben’ which includes Chandkuri and Palasi Gondwana basins in Indian part and Bogra Gondwana Basin in western Bangladesh where thick Gondwana successions are recognised in the subsurface sections of Singra (Singra-1X, Kuchma-X1, Bogra-X1), Jamalganj (EDH-1, 6) and Barapukuria (GDH-40, 43) coalfields. Gondwana bearing boreholes in the western margins of West Bengal Basin (GLS-A, GLS-B, GLS-C) represent a quite separate Gondwana basin of ‘Galsi’ which is located in the southern part of the N–S trending ‘Purnea–Rajmahal–Galsi Gondwanic Graben’. Latest Jurassic–Early Cretaceous Rajmahal Traps cap the Gondwana successions in the above Gondwana basins of West Bengal Basin along with Bogra and Rajmahal Gondwana basins. Rajmahal Traps and its infra- and intertrappean beds are exlcuded from the Gondwana cycle as these beds are marked by the Early Cretaceous marine dinoflagellate cysts, and the Rajmahal volcanism took place after a very long time gap from Late Triassic to Late Jurassic (ca. 78 my). Rajmahal Traps and its infra- and intertrappean beds indeed represent the post-Gondwana syn-rift sequence in West Bengal, Mahanadi and Rajmahal basins, and closely related with the break-up of Indian Plate from the East Gondwanaland during Tithonian (ca. 150 Ma). The post-trappean Late Cretaceous successions mark the initiation of passive-margin phase in this basin with the deposition of marine Bolpur and Ghatal formations.

Palaeobotany and palynology of coprolites from the Late Triassic Chañares Formation of Argentina: implications for vegetation provinces and the diet of dicynodonts

The early Late Triassic Chañares Formation of Argentina contains one of the richest tetrapod-bearing assemblages of this age worldwide and is important for understanding the origin and early radiation of suchians, dinosauromorphs, and mammaliaforms. Here, we describe the fabric and microfossil content of herbivore coprolites produced by large kannemeyeriiform dicynodonts. Identified inclusions are dominated by fragmentary plant debris (wood, cuticles) with minor palynomorphs, the latter being of special significance as they represent the first palynological assemblage obtained for the formation. The palynological assemblage, which is dominated by bisaccate pollen grains, Alisporites and Platysaccus (Umkomasiales = Corystospermales), and minor striate pollen grains and fern spores, is characteristic of the Ipswich Phytogeographic Subprovince. Also present are Ovalipollis and Ellipsovelatisporites, which are typically absent in this phytogeographic subprovince (being characteristic elements of the Onslow Subprovince), but have been reported in the younger Ischigualasto Formation from the same basin. A statistical analysis of Triassic palynofloras across Gondwana results in a grouping containing the Ischigualasto and Chañares formations, with assemblages of East Antarctica, which together comprise a subprovince that is transitional between Ipswich and Onslow floras. The paleobotanical and palynological content of the coprolites also sheds light on the feeding behaviour of dicynodont producers, suggesting low-feeding habits and non-strict selectivity of the food source.

Gondwana Biostratigraphy of the Purnea Basin (Eastern Bihar, India), and its Correlation with Rajmahal and Bengal Gondwana Basins

ABSTRACT Integrated biostratigraphic studies are undertaken on the newly discovered Gondwana successions of Purnea Basin which have been recognized in the subsurface below the Neogene Siwalik sediments. The four exploratory wells, so far drilled in Purnea Basin, indicated the presence of thick Gondwana sussession (± 2450m) with varied lithological features. However, precise age of different Gondwanic lithounits of this basin and their correlation with standard Gondwana lithounits is poorly understood due to inadequate biostratigraphic data. Present biostratigraphic studies on the Gondwana successions in the exploratory wells of PRN-A, RSG-A, LHL-A and KRD-A enable recognition of fifteen Gondwanic palynological zones ranging in age from Early Permian (Asselian-Sakmarian) to Late Triassic (Carnian-Norian). Precise age for the Gondwanic palynological zones, recognized in the Purnea Basin and already established in other Indian Gondwana basins, are provided in the milieu of additional palynological data obtained from the Gondwana successions of this basin. The Lower Gondwana (Permian) palynofloras of Purnea Basin recorded from the Karandighi, Salmari, Katihar and Dinajpur formations resemble the palynological assemblages earlier recorded from the Talchir, Karharbari, Barakar and Raniganj formations respectively, and suggests the full development of lower Gondwana succession in this basin. The Upper Gondwana (Triassic) succession of this basin is marked by the Early and Middle to Late Triassic palynofloras that resemble Panchet and Supra-Panchet (Dubrajpur/Maleri Formation) palynological assemblages, and indicates the occurrence of complete Upper Gondwana succession also in the Purnea Basin. The lithological and biostratigraphic attributes of Gondwana sediments from Purnea, Rajmahal and western parts of Bengal Basin (Galsi Basin) are almost similar and provides strong evidences about the existence of a distinct N-S trending Gondwana Graben, referred as the Purnea-Rajmahal-Galsi Gondwana Graben. Newly acquired biostratigraphic data from the Gondwana sediments of CHK-A, MNG-A and PLS-A wells from central part of Bengal Basin and Bouguer anomaly data suggest that these wells fall in a separate NE-SW trending graben of “Chandkuri-Palasi-Bogra Gondwana Graben”. Although, the post-Gondwana latest Jurassic-Early Cretaceous Rajmahal Traps and and intertrappean beds succeed the Upper Gondwana successions in Rajmahal, Galsi and Chandkuri-Palasi Gondwana basins, but not recorded in the drilled wells of Purnea Basin, instead succeeded by the Neogene Siwalik sediments.

Late Triassic (Carnian– Rhaetian) palynology of Hopen, Svalbard

Triassic strata crop out extensively on the Svalbard Archipelago and subcrop under much of the Barents Sea. However, due to the remoteness of the region, relatively few palynostratigraphic studies of the Upper Triassic succession have been conducted. Consequently, existing palynological zonations for the Late Triassic in the region are of relatively low temporal resolution. In this study, 154 palynological samples from eight outcrop localities on the island of Hopen, Svalbard Archipelago, were analysed. Hopen offers unique insights into the subsea geology of the Barents Sea due to its position as the most southeasterly island of the archipelago. Samples spanning the De Geerdalen, Flatsalen and Svenskøya formations (Kapp Toscana Group) yielded well preserved palynofloras. The dense vertical and lateral distribution of samples makes this the most detailed palynological investigation of LateTriassic strata conducted thus far in the region. Six palynological assemblages were recognised using relative abundance and first stratigraphic appearance data; in ascending stratigraphic order these are the: (1)Leschikisporis aduncus assemblage (late Carnian), (2)Protodiploxypinus spp. assemblage (late Carnian– ? early Norian), (3)Classopollis torosus assemblage (early Norian), (4)Rhaetogonyaulax rhaetica assemblage (early Norian), (5)Limbosporites lundbladii– Quadraeculina anellaeformis assemblage (? late Norian–? Rhaetian) and the (6)Rogalskaisporites ambientis assemblage (? late Rhaetian). The palynological assemblages are compared to previous palynological studies on the island and to existing palynozonations for the region. A revised age interpretation for Hopen is provided based on the integration of palynology and independent chrono- and biostratigraphic evidence. The youngest strata are interpreted to be of Rhaetian age and yielded palynomorph assemblages remarkably similar to contemporaneous assemblages previously described from China, Australia and New Zealand. The study contributes important empirical data concerning the Late Triassic palynofloras along the northern shores of Pangaea.

Permian–Triassic palynostratigraphy in Mailaram area, Godavari Graben, Andhra Pradesh, India

Palynological investigations of five borecores, viz., GAM-3, GAM-6, GAM-7, GAM-8 and GAM-10 from Mailaram area have suggested the occurrence of complete Lower Gondwana succession in Mailaram area. Total nine palynozones have been identified on the basis of dominance, sub-dominance and appearance of various palynotaxa. These palynozones belong to Talchir, Upper Karharbari and Barakar (Early Permian), Raniganj (Late Permian) and Panchet (Early Triassic) palynofloras of Indian Gondwana. The oldest Palynozone-1 demonstrated in borecore GAM-6 (331.4–500 m) and borecore GAM-10 (505.66–581.55 m), is characterized by the dominance of Parasaccites and sub-dominance of Plicatipollenites belongs to Talchir Palynoflora; Palynozone-2 identified in borecore GAM-7 (667–749 m) and borecore GAM-8 (89.75 m) is characterized by the dominance of Parasaccites and sub-dominance of Scheuringipollenites which belongs to Upper Karharbari Palynoflora. Palynozone-3, identified in borecore GAM-6 (149.7–240.05 m) and borecore GAM-8 (84.95 m), is characterized by the dominance of Scheuringipollenites akin to Scheuringipollenites zone of Barakar palynoflora; Palynozone-4, recorded in borecores GAM-3 (294–437.98 m), GAM-7 (453–640.5 m) and GAM-8 (35.35 m) is characterized by the dominance of Faunipollenites and sub-dominance of Striatopodocarpites along with certain stratigraphically significant taxa, viz., Weylandites, Guttulapollenites, Corisaccites, Aurangapollenites and Osmundacidites. Palynozone-5, demarcated in borecore GAM-3 (144.86–221.3 m) and borecore GAM-10 (35.35 m), is distinguished by the dominance of striate disaccates along with at least 30% pollen assigned to Striasulcites; Palynozone-6, identified in borecore GAM-3 (35.1–73.08 m) and borecore GAM-7 (231–423 m), is characterized by the dominance of striate disaccates along with 20–30% of Densipollenites; Palynozone-7, recorded in borecore GAM-7 (206 m), is distinguished by the dominance of Crescentipollenites along with striate disaccates; Palynozone-8, identified in borecore GAM-7 (178.4 m), is characterized by the distinguished presence of taeniate pollen Guttulapollenites. Palynozones 4–8 belong to Raniganj Palynoflora. Palynozone-9, identified in borecore GAM-7 (166 m), is discriminated by the dominance of trilete spore Verrucosisporites and sub-dominance of taeniate pollen Lunatisporites which belongs to Triassic palynoflora. On the basis of palynological data Palynozone-1 (= Talchir palynoflora), Palynozone-2 and Palynozone-3 have been assigned to Early Permian age; Palynozones 4–8 (= Raniganj palynoflora) have been assigned to Late Permian age and Palynozone-9 (= Triassic palynoflora) has been assigned to Early Triassic age. With the aim of correlating the Permian and Triassic sediments of Mailaram area palynological investigations of five borecores were carried out.

Permian Triassic palynofloral transition in Chintalapudi area, Godavari Graben, Andhra Pradesh, India

The entire 606 m-thick sedimentary sequence in borecore MCP-7 from Chintalapudi area, Chintalapudi sub-basin has been lithologically designated as Kamthi Formation. However, the palynological investigation revealed five distinct palynoassemblages, which essentially fall under two groups, one group (Palynoassemblage-I, II and III) having dominance of striate disaccates along with presence of some stratigraphically significant taxa, belongs to Late Permian (Raniganj) palynoflora, while the other group (Palynoassemblages IV and V) shows sharp decline in percentage of characteristic taxa of first group, i.e., striate disaccates, and consequent rise or dominance of taeniate and cingulate cavate spores, belongs to Early Triassic (Panchet) palynoflora. Palynoassemblage-I, II and III (Group I) are characterized by dominance of striate disaccates chiefly, Striatopodocarpites spp. and Faunipollenites spp. along with presence of rare but stratigraphically significant taxa, viz., Gondisporites raniganjensis, Falcisporites nuthaliensis, Klausipollenites schaubergeri, Chordasporites sp., Striomonosaccites, ovatus, Crescentipollenites multistriatus, Verticipollenites debiles, Strotersporites crassiletus, Guttulapollenites hannonicus, G. gondwanensis, Hamiapollenites insolitus, Corisaccites alutus, Lunatisporites ovatus, Weylandites spp. and Vitreisporites pallidus. Palynoassemblage-I is distinguished by significant presence of Densipollenites spp. while Palynoassemblage-II shows significant presence of Crescentipollenites spp. and Palynoassemblage-III differs from the above two assemblages in having significant presence of Guttulapollenites hannonicus. Palynoassemblage-IV (Group II) is characterized by high percentage of taeniate disaccates chiefly Lunatisporites spp., while Palynoassemblage-V (Group II) is characterized by cingulate-cavate trilete spores chiefly, Lundbladispora spp. and Densoisporites spp. Striate disaccates show a sharp decline in these two assemblages. In Chintalapudi area Late Permian and Early Triassic palynoflora has been recorded for the first time indicating existence of Raniganj and Panchet sediments as well. The study further supports the earlier studies of Jha and Srivastava (1996) that Kamthi Formation represents Early Triassic (=Panchet Formation) overlying Raniganj equivalent sediments with a gradational contact.

The quest for chron E23r at Partridge Island, Bay of Fundy, Canada: CAMP emplacement postdates the end-Triassic extinction event at the North American craton

The Partridge Island stratigraphic section at the Bay of Fundy, Maritime Canada, reveals a continental sedimentary succession with the end-Triassic mass extinction level closely followed by basalts of the Central Atlantic Magmatic Province (CAMP). New Paleomagnetic data show that a short reverse magnetic polarity chron, correlative to E23r of the Newark Geomagnetic Polarity Time Scale (GPTS), is present below the extinction event. Organic carbon isotope data and basalt geochemistry further indicate that the onset of CAMP emplacement in the Bay of Fundy was roughly synchronous with emplacement in the Newark basin, but slightly postdates the oldest CAMP volcanism in Morocco by ∼20 ka. These results confirm the potential for long-distance CAMP correlations based on geochemical trace elements, indicate substantiate provincialism of latest Triassic palynoflora, and suggest a very concise period (<<100 ka) of CAMP emplacement in the northern Atlantic region.

Early Triassic Palynomorphs from Manuguru Area of Godavari Graben, Andhra Pradesh

Abstract Palynological analysis of the subsurface sediments from the bore hole 1008 (PK-6&7 blocks) from Manuguru area of Godavari graben has revealed the presence of Early Triassic palynoflora. Quantitative and qualitative palynological analysis of the productive samples have shown that the palynofossil content is predominated by cingulate-cavate spores, viz. Lundbladispora and Densoisporites and taeniate pollen like Lunatisporites in association with other taxa, such as Falcisporites, Alisporites, Klausipollenites, Chordasporites, Verrucosisporites and Osmundacidites. The above recovered palynoflora provides conclusive evidence for the presence of Early Triassic sediments equivalent to Panchet in the Manuguru area of Godavari graben. This is the first record of Early Triassic palynoflora in the Manuguru area. This corroborates the findings of Jha and Srivastava (1996) that the Lower Kamthi Formation represents the Early Triassic sequence equivalent to the Panchet Formation.

Late Triassic palynoflora from the Pranhita–Godavari Valley, India: evidence from vertebrate coprolites

Vijaya, Prasad, G.V.R. & Singh, K., June, 2009. Late Triassic palynoflora from the Pranhita–Godavari Valley, India: evidence from vertebrate coprolites. Alcheringa 33, 91–111. ISSN 0311-5518. The Upper Triassic Maleri Formation, represented by red clays and sandstones, has to date not produced any plant macrofossils or palynomorphs. Many spiral and non-spiral coprolites collected during this study from the Maleri Formation of the Pranhita-Godavari Valley were analysed for palynomorphs. Based on shape, nature of coiling and size, the Maleri coprolites are classified into seven groups. Of these, only Group-I, Type 5 (non-spiral) and amphipolar (spiral) types yielded diverse gymnospermous and pteridophytic spores, pollen, other plant debris and sparse fungal spores and algal remains. Occurrences of Antulsporites varigranulatus, Aratrisporites spp., Cadargasporites baculatus, Dubrajisporites isolatus, Enzonalasporites vigens, Foraminisporis coelatus, Grandispora spinosa, Kraeuselisporites saeptatus, Polycingulatisporites reduncus, Staurosaccites spp., Tethysispora unica and Tikisporites balmei confirm a Late Triassic age for the coprolite-bearing red clays. Records of Classopollis classoides and Callialasporites turbatus/dampieri in these assemblages more precisely suggest a Norian to Rhaetian age. The non-spiral coprolites were possibly produced by aquatic piscivorous animals whereas the spiral coprolites may have been produced by an as yet unidentified fish taxon. The coprolite-producing animals (spiral and non-spiral groups) possibly ingested gymnospermous and pteridophytic plant remains passively along with water or their herbivorous prey.

Microfloristic provincialism in the Upper Triassic Circum-Mediterranean area and palaeogeographic implication

This study represents a contribution to the developing knowledge about the microfloristic provincialism affecting Upper Triassic palynoflora. The compositional differences existing between the Onslow and the Ipswich microfloras are mainly based on the presence, in the Onslow microflora, of a diverse and more varied group of gymnosperm pollen grains, including typical European elements. In this study, the palynological assemblages recovered from Carnian successions of the western Tethyan margin (Sicily, Tunisia, Albany, Libya and Israel) are compared with those of West Timor microfloral assemblages, which have been referred to the Onslow microflora of southern hemisphere. They contain several common taxa, mainly consisting of conifer miospores widely recorded in Carnian European successions and less frequently recovered in the Carnian of western and eastern Australia. The number of Circum-Mediterranean sporomorphs in the Onslow microflora assemblages is wider than previously thought, providing new evidences to extend the distribution of the Onslow microflora to include Carnian associations formerly assigned to the Circum-Mediterranean assemblages. These broad microfloral affinities seem to indicate the existence of a homogeneous microflora that maintains, with minor variations, its composition from western Tethys coasts to the northern Australian margin (West Timor). The parent plant community grew in a coastal environment, along the continental margins; the establishment of an equable climatic regime influenced by warm equatorial currents and suitable humid conditions probably conditioned its diffusion. It has long been recognised that the strong floral provinciality which characterised the Late Triassic world gave way to a more homogeneous flora in the Early Jurassic. The decrease in macrofloral diversity is associated with a less pronounced microfloristic provincialism, which in turn coincides with the rise, to strong dominance, of cheirolepidiaceous conifers (Circumpolles producers). This important microfloristic event occurs in the southern hemisphere during the Early Jurassic, however this study reveals their incipient diffusion during the Norian.

Triassic palynoflora from the Mahuli-Mahersop area, Singrauli Coalfield (Southern Extension), Sarguja district, Chhattisgarh, India

Triassic palynoflora from the Mahuli-Mahersop area, Singrauli Coalfield (Southern Extension), Sarguja district, Chhattisgarh, India

Earliest Triassic (Induan) spores and pollen from the Junggar Basin, Xinjiang, northwestern China

Permian–Triassic boundary strata cropping out in the southern Junggar Basin contain a continuous and varied fossil record, making this fluvio-lacustrine succession a potential candidate for a non-marine boundary stratotype. Abundant, diverse and well preserved miospores are recorded and illustrated from the upper part of the Guodikeng Formation and the basal part of the Jiucaiyuan Formation, comprising 92 species and 48 genera, as well as some acritarchs. Seven new species ( Anapiculatisporites decorus Ouyang et Norris, sp. nov., Baculatisporites uniformis Ouyang et Norris, sp. nov., Kraeuselisporites varius Ouyang et Norris, sp. nov., Lapposisporites echinatus Ouyang et Norris, sp. nov., Klausipollenites angustus Shu et Norris, sp. nov., Alisporites exilis Ouyang et Norris, sp. nov., Pilasporites perreticulatus Ouyang et Norris, sp. nov.) and 8 new combinations are proposed. Pteridophytic spores and gymnospermous pollen are almost equally diverse, comprising 45 species in 20 genera, and 43 species in 25 genera, respectively. Pteridophytes are numerically more important, notably Limatulasporites, Kraeuselisporites, Lundbladispora, Anapiculatisporites and Verrucosisporites, but also prominent are bisaccate pollen of Falcisporites, Klausipollenites and Alisporites. Less abundant taeniate pollen are largely bisaccate. These palynofloras are grouped together as the Lundbladispora– Lunatisporites– Aratrisporites Assemblage, argued to be Early Triassic (early Induan), and comprising both newly evolved Mesozoic taxa (herbaceous and shrubby lycopsids, coniferous trees, pteridosperms) and relict Paleozoic taxa (sphenophyllids, cordaitaleans and possibly Paleozoic lycopods). The lower boundary of the Triassic in the section is redrawn somewhat lower than by previous authors. The transitional nature of the Permian–Triassic palynofloras and of the paleophytoprovinces is discussed; neither indicates a sudden catastrophic event affecting terrestrial floras at the P–T boundary on a global scale. The Early Triassic vegetation appears to have grown under humid sub-tropical conditions in lowland flood plains and marshes dominated by hydrophilous and mesophilous pteridophytes and pteridosperms, but with locally drier upland environments supporting xerophilous and mesophilous conifers and pteridosperms. The Induan vegetation is closely comparable to that of the Angara, especially the Subangara Province, although it contains some elements of the Euramerican Province in association with a few Gondwanan, Cathaysian and cosmopolitan taxa.

Chronology of nappe assemblage in the Pan-African Dahomeyide orogen, West Africa: evidence from 40Sr/39 mineral ages : Attoh K., Dallmeyer R.D. & Affaton P., Precambrian research, 1997, 82/1–2 (153–171)

Permian–Triassic boundary strata cropping out in the southern Junggar Basin contain a continuous and varied fossil record, making this fluvio-lacustrine succession a potential candidate for a non-marine boundary stratotype. Abundant, diverse and well preserved miospores are recorded and illustrated from the upper part of the Guodikeng Formation and the basal part of the Jiucaiyuan Formation, comprising 92 species and 48 genera, as well as some acritarchs. Seven new species (Anapiculatisporites decorus Ouyang et Norris, sp. nov., Baculatisporites uniformis Ouyang et Norris, sp. nov., Kraeuselisporites varius Ouyang et Norris, sp. nov., Lapposisporites echinatus Ouyang et Norris, sp. nov., Klausipollenites angustus Shu et Norris, sp. nov., Alisporites exilis Ouyang et Norris, sp. nov., Pilasporites perreticulatus Ouyang et Norris, sp. nov.) and 8 new combinations are proposed. Pteridophytic spores and gymnospermous pollen are almost equally diverse, comprising 45 species in 20 genera, and 43 species in 25 genera, respectively. Pteridophytes are numerically more important, notably Limatulasporites, Kraeuselisporites, Lundbladispora, Anapiculatisporites and Verrucosisporites, but also prominent are bisaccate pollen of Falcisporites, Klausipollenites and Alisporites. Less abundant taeniate pollen are largely bisaccate. These palynofloras are grouped together as the Lundbladispora–Lunatisporites–Aratrisporites Assemblage, argued to be Early Triassic (early Induan), and comprising both newly evolved Mesozoic taxa (herbaceous and shrubby lycopsids, coniferous trees, pteridosperms) and relict Paleozoic taxa (sphenophyllids, cordaitaleans and possibly Paleozoic lycopods). The lower boundary of the Triassic in the section is redrawn somewhat lower than by previous authors. The transitional nature of the Permian–Triassic palynofloras and of the paleophytoprovinces is discussed; neither indicates a sudden catastrophic event affecting terrestrial floras at the P–T boundary on a global scale. The Early Triassic vegetation appears to have grown under humid sub-tropical conditions in lowland flood plains and marshes dominated by hydrophilous and mesophilous pteridophytes and pteridosperms, but with locally drier upland environments supporting xerophilous and mesophilous conifers and pteridosperms. The Induan vegetation is closely comparable to that of the Angara, especially the Subangara Province, although it contains some elements of the Euramerican Province in association with a few Gondwanan, Cathaysian and cosmopolitan taxa.

Gondwanan floristic and sedimentological trends during the Permian–Triassic transition: new evidence from the Amery Group, northern Prince Charles Mountains, East Antarctica

The Permian–Triassic boundary within the Amery Group of the Lambert Graben is placed at the contact between the Bainmedart Coal Measures and overlying Flagstone Bench Formation, based on the first regular occurrence of Lunatisporites pellucidus and the first appearance of Aratrisporites and Lepidopteris species. The Permian-Triassic boundary is marked by the extinction of glossopterid and cordaitalean gymnosperms, and by the disappearance or extreme decline of a range of gymnospermous and pteridophytic palynomorph groups. Earliest Triassic macrofloras and palynofloras of the Flagstone Bench Formation are dominated by peltasperms and lycophytes; corystosperms, conifers, and ferns become increasingly common elements of assemblages through the Lower Triassic part of the formation and dominate floras of the Upper Triassic strata. The sedimentary transition across this boundary is conformable but marked by a termination of coal deposits; overlying lowermost Triassic sediments contain only carbonaceous siltstones. Typical red-bed facies are not developed until at least 100 m above the base of the Flagstone Bench Formation, in strata containing ?Middle Triassic palynofloras. Across Gondwana the diachronous disappearance of coal deposits and appearance of red-beds is suggestive of a response to shifting climatic belts, resulting in progressively drier seasonal conditions at successively higher palaeolatitudes during the Late Permian to Middle Triassic. The abrupt and approximately synchronous replacement of plant groups at the Permian–Triassic boundary suggests that factors independent of, or additional to, climate change were responsible for the turnover in terresrtial floras.

Palynofloras from the Permian, Triassic and Jurassic of New Caledonia

Abstract Palynofloral assemblages are recorded from 33 productive samples from sediments of Permian (Djulfian), Early Triassic (Griesbachian), Late Triassic (Norian), and Early and Middle Jorassic age. All are from marine sequences dated by associated invertebrate faunas. The assemblages are dominated by miospores, in conformity with their nearshore origin. They are similar to palynofloras of equivalent age from New Zealand and eastern Australia. In relation to provincialism which has been documented for Australian Triassic palynofloras, the New Caledonia material can be assigned to the cool temperate Ipswich Microflora, rather than to the warm temperate Onslow Microflora.

A middle to late triassic palynoflora from the kalapani limestone formation, malla johar area, tethys himalaya, India

A Triassic palynoassemblage recovered from a horizon high in the Kalapani Limestone Formation of the Malla Johar Supergroup, Tethys Himalaya, includes spores and pollen referred to 44 genera and 68 species. Of these one genus — Tethysispora, and four species — Tethysispora unica, T. playfordii, Striatopodocarpites auriculatus and Lunatisporites tethysensis are new. This assemblage is diverse and contains elements similar to those occurring in Laurasian and Gondwanan palynofloras. The Tethyan Triassic sediments had their provenance from the Indian peninsula and the major plant life around the area was related to Indian mainland floras. However, a mild and distant European and Angara influence is also evident.

Stratigraphic position and age of plant bearing Nidpur beds

The Gopad River Section near Nidpur has yielded a rich and diversified flora showing the dominance of Dicroidium associated with the culmination of non-straite bisaccate pollen. Gymnosperms are the main components of this fossil assemblage. Dicroidium a widely disseminated taxon in the Gondwanaland has restricted stratigraphical range. It has been considered to be an infallible indicator of Triassic time. Furthermore, the consistency of usual association of Pteruchus with Dicroidium also supports a Triassic age for Nidpur beds. Confirmatory evidence of the Triassic age is also provided by the frequent occurrence of Alisporites indicus correlated with the variable pollen (Aisporites complex) of Pteruchus. The dominant pollen Satsangisaccites distinguishes Nidpur assemblage from other palynofloras whereas Nidipollenites have now been reported from other Triassic palynofloras.

Palynology and the triassic/jurassic boundary

Characteristic latest Triassic palynofloras are first developed in the Norian with the association of Camarozonosporites laevigatus, Chasmatosporites apertus, C. magnolioides, Cingulizonates rhaeticus, Densosporites fissus, Granuloperculatipollis rudis, Kyrtomisporis laevigatus, K. speciosus, Limbosporites lundbladii, Ovalipollis ovalis, Perinosporites thuringiacus, Rhaetipollis germanicus, Ricciisporites tuberculatus, Selagosporis mesozoicus, Semiretisporis gothae, Triancoraesporites ancorae, Zebrasporites interscriptus and Z. laevigatus. These forms persist into the Rhaetian and, in some instances, into the basal part of the overlying Jurassic. Palynofloral resolution of the Triassic/Jurassic boundary is largely based on the disappearance of typically late Triassic morphotypes; undoubtedly post-Triassic species, e.g. Cerebropollenites mesozoicus and C. thiergartii, however, are rarely conspicuous elements of the basal Jurassic palynofloras and may not become dominant elements until the late Hettangian or Sinemurian. A palynological definition of the Triassic/Jurassic boundary is further complicated by the lack of agreement on the legitimacy of the Rhaetian Stage, the location of the type section of the basal zone of the Hettangian Stage, and the uncertainty over the precise definition of the top Triassic/basal Jurassic within the stratotype sections proposed. In this context, the unsatisfactory nature of a palynologically defined Triassic/Jurassic boundary in northwest Europe is discussed.

Late Triassic palynofloras of North America and their European correlatives

Upper Triassic continental strata in the United States contain rare horizons which yield pollen assemblages. The Dockum Group and Chinle Formation of the American Southwest, as well as certain rock units within the Deep River, Richmond, and Taylorsville Basins of the Newark Group, contain palynomorphs which exhibit stratigraphically restricted ranges in Europe. The presence of Vallasporites ignacii, Camerosporites secatus and Ovalipollis ovalis in the Dockum Group, Chinle Formation, Cumnock Formation of the Deep River Basin, Vinita Formation of the Richmond Basin, and unnamed units in the Taylorsville Basin suggest that all these units are approximately contemporaneous. The occurrence of these and other stratigraphically diagnostic pollen taxa, particularly Patinasporites densus, further indicates a Middle to Late Karnian age for these units. The palynostratigraphy also implies that the Pekin Formation of the Deep River Basin is slightly older than the above mentioned units.