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Palynological and petrological studies have been undertaken on the Gondwana coal and associated lithologies encountered in borehole EBM-2 of East Bokaro coalfield of Damodar Basin, India. The palynological investigation resulted in the recognition of Assemblage-III ( Densipollenites, 27.9 m-214.30 m), Assemblage-II ( Striatopodocarpites + Faunipollenites, 225.00 m-297.60 m) and Assemblage-I ( Faunipollenites + Scheuringipollenites, 307.00m-433.00 m). Lithofacies study was also done for better understanding of the preservation and abundance/paucity of the spores and pollen in different lithologies as the current borehole has significant thickness of mudstones, shales and siltstone. Palynofacies study and Petrographical studies of coal samples encountered in the borehole were used to determine the depositional environment of the coal precursor peat swamp. Palynological data has revealed the presence of younger Raniganj palynoflora between 27.00-214.30 m depth that is lithologically defined as Barren Measures Formation. This spore pollen study has proved that these sediments were deposited during late early Permian to late Permian period. Further the maceral analysis of organic sediments as well as the Thermal Alteration Index (TAI) has revealed that the coaly shale at 336.5 m depth has hydrocarbon generation potential. [ABSTRACT FROM AUTHOR]

The present work deals with the palaeoenvironment and depositional setting of the subsurface sediments from bore hole RT-4 of Tamra block from Raniganj coalfield of Damodar Basin, India. Nineteen shale samples were subjected to palynological and coal petrographical analyses. On the basis of botanical affinity between the miospores and the parent plants as well as the different plant groups, each coal plant assemblage was determined. The dominance of bisaccates such as Scheuringipollenites, Faunipollenites (= Protohaploxypinus), Striatopodocarpites and presence of monosaccates such as Densipollenites, Parasaccites reflect a peat forming community composed mainly of gymnosperms. Subordinate trilete spores derived from filicopsids ( Cyclogranisporites, Horriditriletes, Brevitirletes, Callumispora, Microbaculsispora, Microfoveolatispora, Cyclobaculisporites), lycopsids ( Indotriradites, Gondispoirtes and Didecitriletes) and sphenopsids ( Laevigatosporites ) are less abundant occurring in variable proportions reflecting a hypautocthonous taphocenose. Presence of Botryococccus algae has been recorded. Palynofacies and petrographic analyses suggest deposition in open mires in a Limnic to limno-telmatic conditions with intermittent flooding of the site. [ABSTRACT FROM AUTHOR]

Petrographic analysis of the coals from bore core EBM-1 of East Bokaro Coalfield revealed characteristic changes as a result of thermal alteration by an intrusive body. The enhancement of 'rank' (increase in the VR% values) is observed in the heat affected coal in the lower part of the bore core. The vitrinite in the coal at a depth of 984.95 m showed devolatilization vacuoles and initiation of mosaic structure due to heat alteration, dessication cracks and micropores. Meta-liptinite having reflectance value higher (1.67%) than that of the host vitrinite (1.09% - 1.36%) was also recorded. Bi-reflectance values of the un-altered coals were normal in the range of 0.06% - 0.09% where as the altered coal at a depth of 984.95 m showed an abnormal increase in the values (0.23%). Presence of secondary injected mineral matter and char particles further indicate the effect of thermal alteration. Palynological investigation of both altered and un-altered coal reveals that the palynomorphs recovered from the altered coal are dark and opaque due to the charring effect while the palynomorphs from un-altered coals exhibit a clear internal structure and can be easily identified. [ABSTRACT FROM AUTHOR]

Macroscopic charcoal is recovered from the sub-surface sediments from Bore core SKB-1 which intersected Barren Measure Formation and Raniganj Formation of South Karanpura coalfield. These charcoal particles are widely accepted to be of palaeowildfire products and this study contributes to the Middle and Late Permian wildfire data of Indian peninsula. In the present investigation the charcoal particles are studied using reflected light, transmitted light and Scanning Electron microscopy to document their anatomical structure, morphology and temperature of formation. The inertinite reflectance data reveal that these charcoals were formed at a temperature of 600° C which is evident by the homogenized cell walls as homogenization takes place at temperatures above 500° C. Petrographic analysis reveals high inertinite content and the calculated Gelification Index and Tissue preservation Index suggest that the sediments from which the charcoal particles were retrieved were deposited in a dry forest swamp which was conducive for the forest fire to propagate as the forest litter provided the fuel load. The morphological characters of charcoal were utilized in delineating its taphonomy and it indicates that they are hypautochthonous in nature. [ABSTRACT FROM AUTHOR]

Palynological investigations are carried out on approximately 538.00-m thick Gondwana strata from borehole SKB-1, Binja Block, South Karanpura Coalfield in Jharkhand. Based on the distribution pattern of age marker palynotaxa, two distinct palynoassemblages are identified. Palynoassemblage-I in the lithologically designated Barren Measures and Barakar formations, between 552.00 and 53.20 m depth show dominance of striate bisaccate ( Striatopodocarpites, Crescentipollenites, and Faunipollenites) and abundance of nonstriate bisaccate ( Scheuringipollenites). Upward the Palynoassemblage-II (39.50-13.80 m depth) is rich in striate bisaccate ( Striatopodocarpites and Crescentipollenites) and significant enveloping monosaccate Densipollenites magnicorpus pollen. These strata have been equated with Raniganj Formation of Latest Permian age. The First Appearance Datum (FAD) of Arcuatipollenites pellucidus, Playfordiaspora cancellosa, Alisporites sp., Falcisporites sp. and Krempipollenites indicus observed at 13.80 and 39.50 m depth, mark the transition of Permian into the Lower Triassic. The FADs of Guttulapollenites spp. at 49.10 and 504.70 m, Goubinispora morondavensis at 415.90 m, Alisporites ovalis and Arcuatipollenites sp. at 526.70 m is observed and suggest that these sediments are equivalent to Raniganj Formation, Late Permian in age. [ABSTRACT FROM AUTHOR]

The Gondwana sediments comprising fine-grained shales, carbonaceous shales, sandstones and the coal horizon in borecore RT-4 (approximately 547.00m thick) from Tamra block, Raniganj Coalfield, Damodar Basin, are analyzed palynologically. Based on the distribution pattern of marker palynotaxa, two assemblage zones are identified. In the Barren Measures Formation, dominance of enveloping monosaccate ( Densipollenites) along with striate bisaccate ( Striatopodocarpites, Faunipollenites) pollen taxa, and the FAD's of Kamthisaccites and Arcuatipollenites observed at 30.75, have equated this strata (30.75-227.80 m thick) with the Raniganj Formation of Late Permian in age. Downwards in the Barakar Formation, between 423.80-577.70 m depths, an abundance of non-striate ( Scheuringipollenites) and striate ( Faunipollenites and Striatopodocarpites) bisaccate pollen taxa is observed, that dates late Early Permian in age. Fair occurrences of hyaline, distorted and blackish-brown plant matter is observed within 231.00-408.40 m depths. Present study infers the existence of the Raniganj Formation in the lithologically delimited Barren Measures Formation in the study area, and the underlying unproductive strata (approx. 177.40m) might represent the part of the Barren Measures Formation. [ABSTRACT FROM AUTHOR]

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]