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We report studies of petrography, palynofacies, charcoal and adpressed plant fossils for the coal-bearing Jagannath section in the Talcher Coalfield, Mahanadi Basin, India, to improve understanding of the age, palaeoecology and depositional setting of this palaeo-mire. Palynology is indicative of the Scheuringipollenites barakarensis assemblage, suggesting an Early Permian (Artinskian) age for the studied section. The age of the studied section is inferred based on correlation with coeval assemblages across Gondwana. Palynoassemblages have more similarity with those of Africa than South America. Petrographic indices suggest that peat-forming vegetation accumulated mainly in telmatic settings under ombrotrophic-mesotrophic (intermittent fluctuating) hydrological conditions. Palynofacies suggest that the deposition of organic matter (by high energy fluvio-deltaic agents) took place in an oxic to occasionally dysoxic setting. Megaflora comprise a low diversity assemblage dominated by Equisetales (Schizoneura and Paracalamites), with less common Glossopteridales (Glossopteris , Gangamopteris) and Filicales (Dichotomopteris) indicative of dense arborescent vegetation. Numerous fossil macrocharcoal fragments indicate the repeated occurrence of wildfires in the catchment area. The high abundance of pyrogenic inertinites in Permian coals of Gondwana may indicate a high-fire phase of Earth history linked to elevated atmosphere oxygen level, and our current study further substantiates this idea demonstrating the occurrence of fire, not only in seasonally dry ecosystems but also in peat forming ecosystems under humid conditions. Our multiproxy study is significant for understanding Permian peat-forming ecosystems and environments and provides a robust age assessment based on inter and intra-basinal correlations of coeval sequences across the Gondwana. • An integrated approach depicting the palaeovegetation and depositional environment • Study resolves the ambiguity regarding the age of studied sediments in this basin • Accumulation of organic matter occurred under dysoxic-oxic conditions • Fossil charcoal indicate occurrence of palaeowildfires in the source area • Macerals group indicate significant contribution of higher plants for peat formation [ABSTRACT FROM AUTHOR]

Miofloral and fossil charcoal analyses of the Permian deposits of the Barakar and Motur formations from core PKK-2B, located in the Pench-Valley Coalfield, Satpura Basin (India) were carried out to assess the floral diversity, evidence for palaeo-wildfire and age. Two distinct palynoassemblages are identified: Faunipollenites varius palynoassemblage and Gondisporites raniganjensis palynoassemblage dated as Kungurian (Cisuralian) and Guadalupian (Wordian-Capitanian), respectively. These assemblages show dominance of pollen attributable to Glossopteridales followed by Cordaitales and Coniferales. The occurrence of charcoal at two levels in the sedimentary sequence indicates the occurrence of repeated wildfires in the surrounding area. Macroscopic charcoal fragments exhibit anatomical features such as bordered pitting, rays and helical thickenings on cell walls of tracheids suggesting a gymnospermous wood affinity. Most of the charcoal specimens exhibit rounded edges suggesting an allochthonous origin. Furthermore, fusinite reflectance (1.03–6.61%) of studied charcoal/inertinite fragments suggests that the temperature was in the range of ~305–962°C during charring. This indicates co-occurrence of high-temperature crown fires, together with medium- and low-temperature surface and ground fires, respectively. Our data emphasise the dominance of gymnospermous vegetation during the Permian in India and adds further evidence for the widespread occurrence of wildfires during this period in India and on entire Gondwana as well. [ABSTRACT FROM AUTHOR]

The Permian–Triassic Mass Extinction (PTME) event was the largest bio crisis to date, adversely affecting life on land and sea. The PTME event is evidenced in India by the destruction of glossopterids with immense loss of peat-forming vegetation, its replacement by stress-tolerant lycopsids, Lilliput Effect and the presence of numerous acritarchs and abnormal pollen grains. However, there are no reports for algal or acritarch spikes. We document, for the first time, an acritarch spike in the Indian subcontinent from the uppermost Permian to Lower Triassic sequence from the Pranhita–Godavari (P-G) Basin. Lithostratigraphically, the late Permian and Early Triassic aged deposits in the P-G basin are designated as the Kamthi Formation. The formation has a very rich and diverse assemblage of pollen grains, spores and acritarchs. Based on a palynological study, an abundance of Leiosphaeridia dessicata comb. nov. emend. has been identified from sediment samples from the two bore cores (MCP-7 and MCP-8) of the Chintalapudi sub-basin, P-G basin. The acritarch appearance and abundance occurred in synchronization with the floral shift. The acritarch appears along with the stress-tolerant lycopsid spores in the uppermost Permian assemblage and increases in accordance with lycopsid spores in the Lower Triassic assemblages. The morphology of Leiosphaeridia dessicata comb. nov. emend. relates its close affinity with an extant marine algal cyst of Acetabularia acetabulum. Moreover, the presence of gammacerane and methylate chromans in the host sediment indicates the hypersaline water column during the deposition. Thus, based on the presence of marine and hypersaline biomarkers and affinity of L. dessicata comb. nov. emend. with marine alga (probably Prasinophyceae or Chlorophyceae) infer that the deposition during the uppermost Permian and Lower Triassic occurred under shallow marine conditions, contradictory to the earlier belief that Indian Upper Permian and Triassic deposits are entirely terrestrial. The possible marine incursion in the P-G basin may have occurred from the eastern continental margin along western Australia or through a passage between the Indian southern margin and the west margin of Antarctica. [Display omitted] • Leiosphaeridia dessicata comb. nov. emend., is the first report of acritarch spike from India. • L. dessicata comb. nov. emend. closely resembles Acetabularia acetabulum : a marine alga. • L. dessicata comb. nov. emend. spike infers a devastating impact of PTME on marine phytoplankton biota. • Marine incursion in India during the late Permian and Early Triassic time. • The study opens many avenues of understanding the palaeogeography and extent of palaeo-ocean with respect to Gondwana. [ABSTRACT FROM AUTHOR]