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Early Permian floral diversity and palaeodepositional environment of the Lower Permian Rajhara sequence of Damodar Basin have been studied based on mega-, microfossil and geochemical proxies. Even though Gondwana sediments are generally considered as fluvio-lacustrine deposits, recent studies indicate marine inundations with patchy records. Here in the present study, an attempt has been made to address the changeover from fluviatile to shallow marine conditions and also to address the palaeodepositional aspects. Luxuriant vegetation during deposition of the Lower Barakar Formation generated thick coal seams. The macroplant fossil assemblage shows Glossopteridales, Cordaitales and Equisetales comprising one palynoassemblage with the dominance of bisaccate pollen grains having glossopterid affinities. However, Lycopsids are absent in the megafloral record and are represented in megaspore assemblage. The present floral assemblage led to envisage the presence of dense forest with swampy conditions and prevalence of warm and humid climate during the deposition of Barakar sediments. Correlation with the coeval Indian assemblages and those from other Gondwanan continents also supports an Artinskian age and reveals a stronger affinity with flora of Africa than that of South America. Biomarker analysis reveals low pristane/phytane values (0.30–0.84), noticeable absence of hopanoid triterpenoids and long-chain n-alkanes that is attributed to the obliteration of organic compounds and subsequent alteration of composition due to thermal effect. The high chemical index of alteration, A–CN–K plot and PIA also suggest severe denudation under a warm/humid climate. The V/Al2O3 and P2O5/Al2O3 indicated freshwater–near-shore conditions. However, signature of possible marine influence is identified from Th/U and Sr/Ba ratios resulted from the eustatic fluctuations during Permian. [ABSTRACT FROM AUTHOR]

A palynological analysis of borehole RB-1, Raniganj Coalfield, Damodar Basin, has been presented here. Based on the quantitative analysis of the spores and pollen grains of the productive samples, three palynoassemblages have been identified: Palynoassemblage-I demarcated at a depth between 335.00 and 284.00 m is distinguished by the dominance of nonstriate bisaccate pollen Scheuringipollenites and subdominance of striate bisaccate pollen Faunipollenites suggestive of an early Permian (Artinskian) age; Palynoassemblage-II identified at a depth between 278.00 and 32.00 m shows the prominence of striate bisaccate mainly Faunipollenites, Striatopodocarpites and subdominance of Scheuringipollenites signifies late early Permian (Kungurian) age, and the youngest Palynoassemblage-III marked at a depth between 30.00 and 03.00 m contains dominance of striate disaccates pollen, viz., Striatopodocarpites, Crescentipollenites, and monosaccate pollen Densipollenites spp. (D. invisus, D. densus, D. magnicorpus) corroborate with the latest Permian Raniganj (Lopingian) age. The rare occurrence of Densoisporites contactus and Lundbladispora warti in the assemblage, define the upper limit of the Raniganj Formation. The assemblages have been correlated with the Indian as well as other Gondwanian continents. The dominance of gymnosperms pollen glossopteridales, conifers, and cordaites, lesser quantitative spores of lycopsids, sphenopsids, filiciopsids algal elements indicate that the palaeoclimatic condition was warm and high humid, during the deposition of these sediments in the study area of the Raniganj Coalfield. Research Highlights: Palynological study has been carried out for the subsurface coal deposits from the borehole RB-1, drilled at Raniganj Coalfield to attempt to establish chronology of the sediments. The palynological investigation reveals three palynoassemblage zones and dated as early to latest Permian (Artinskian to Lopingian) age and this assemblage reveals the dominance of gymnosperms plant group such as Glossopteridales followed by conifers and cordaitales. The FADs (First appearance of Datum) of Densoisporites contactus, Lundbladispora warti and Lunatisporites pellucidus in the assemblage III indicate the end of Permian period. The overall palynological composition suggests that a warm to very hot with medium to low humidity climatic condition were prevailing in the study area. [ABSTRACT FROM AUTHOR]

Macroscopic fossil charcoal fragments have been recovered from the borehole AK-19 (at a depth of 120.00 m) drilled at the Astona-Kothurna coal block, Wardha valley coalfield. In general, the occurrence of charcoal in sediments is accepted as a direct indicator for palaeo-wildfires. The charcoal fragments exhibits well preserved homogenized cell walls as well as anatomical details such as uniseriate and biseriate pitting patterns on tracheid walls under Field Emission Scanning Electronic Microscope (FESEM), suggesting a gymnospermous wood affinity of the studied material. The excellent preservation, their large size and almost unabraded edges of charcoal fragments suggest a par-autochthonous origin. These findings add further evidence for the widespread occurrence of such wildfires during the Early Permian not only in India, but on the entire Gondwana continent. [ABSTRACT FROM AUTHOR]

A rich Glossopteris dominated plant fossils assemblage is recovered from the Barakar Formation of Lalmatia coal mine, Hura coalfield of Rajmahal Basin, Godda district, Jharkhand, India. The assemblage includes Glossopteris, Gangamopteris and Noeggerathiopsis (leaf forms) along with Vertebraria (root form). There are 4 genera and 14 species of megafossils in the collection, which includes 10 species of Glossopteris, two species of Gangamopteris and one species of Noeggerathiopsis and Vertebraria each. The flora, although similar to that of the Barakar Formation of the Damodar Basin complex, exhibit unique characteristics and is of Artinskian to Kungurian in age. The palynoassemblage recovered in the section reveals the dominance of genus Scheuringipollenites and sub-dominance of Faunipollenites (=Protohaploxypinus) along with Parasaccites, Potonieisporites, Barakarites, Plicatipollenites, Striomonosaccites, Striatopodocarpites, Crescentipollenites, Verticipollenites, Rhizomaspora, Distriatites, Primuspollenites, Striasulcites, Lunatisporites, Guttulapollenites, Platysaccus, Microfoveolatispora, Microbaculispora, Horriditriletes, Tiwariasporis and Weylandites, which demonstrates an early Permian age (Artinskian). The palynoassemblage indicates that the sediments belong to the lower part of the Barakar Formation. Biomarker analysis suggests varying organic matter input during the deposition of the studied sequence. Diterpane compounds and megafossil evidences suggest Glossopteris were the dominant flora along with conifers. Bacterial alteration of the organic matter is inferred from the hopane compounds. The δ13C value of organic matter associated with the carbonaceous shale directly corroborates with the typical δ13C values of the Permian time and is suggestive of warm and humid climatic conditions. [ABSTRACT FROM AUTHOR]

Macro and miofloral analyses of coal-bearing sequences of the Jarangdih coal mine, Damodar Basin, were carried out to infer the floral diversity, age assessment, and the palaeoenvironment during the deposition of the Barakar Formation in this area. Damodar Basin, one of the five major Gondwana basins in India, is considered as the reference basin for inter-basinal age correlations. The Barakar strata of this colliery have yielded a diverse macroflora consisting of the groups Glossopteridales (Glossopteris, Vertebraria, Gangamopteris, fructifications, and stem casts) and Equisetales (Phyllotheca indica, Schizoneura gondwanensis, and Paracalamites sp.). The genus Glossopteris dominates the assemblage with 16 species viz. G. arberi, G. communis, G. churiensis, G. giridihensis, G. indica, G. intermedia, G. intermittens, G. leptoneura, G. linearis, G. mohudaensis, G. recurva, G. searsolensis, G. stenoneura, G. taenensis, G. tenuifolia, and G. tenuinervis. The leaves of Glossopteris leptoneura have impressions of male sporangia adhered on them. The groups Lycopodiales, Coniferales, Sphenophyllales, and Filicales are not represented as macrofloral remains; however, their presence is recorded in the palynoassemblage. The palynological analysis has revealed only one palynoassemblage characterised by the dominance of striate bisaccate palynomorphs mainly Faunipollenites and non-striate bisaccate pollen—Scheuringipollenites. The other stratigraphically significant palynotaxa are Striatopodocarpites, Verticipollenites, Crescentipollenites, Striatites, and Arcuatipollenites. The recovered palyno- and megafloral assemblages suggest the late early Permian (Kungurian) age to the Barakar strata of Jarangdih coal mine and prevalence of moderately warm climate during their deposition. [ABSTRACT FROM AUTHOR]

The palynological and palynofacies studies have been undertaken on the sub-surface sediments of borehole AK-19 from Asthona area of the Wardha coalfield, India. The present investigation has revealed the existence of two distinct palynological assemblages, which have been designated as palynoassemblage - I and II respectively. The former, has shown a predominance of monosaccates viz., Parasaccites, Plicatipollenites, Potonieisporites, and Crucisaccites, whereas, the latter is characterized by the dominance of striate bisaccates such as Faunipollenites and subdominance of non-striate bisaccate Scheuringipollenites along with other striate forms such as Striatopodocarpites, Crescentipollenites, and Rhizomaspora. The other genera recorded mainly includes Parasaccites, Indotriradites, and Callumispora, which suggests that primarily herbaceous and the arborescent plants where luxuriantly growing in the forest with the prevalence of hygrophilous and mesophilous environmental conditions. The recovered palynoassemblages are governed mainly by the gymnosperms such as glossopterids, conifers, and cordaites, etc., flourished in near shore areas in riverine, lacustrine conditions as well as in large swamps and marshy habitat with the prevalence of initially cold climatic conditions (Palynoassemblage-I) which later on became temperate (Palynoassemblage-II).The present palynoassemblages have a closer affiliation with the known early Permian palynofloras of other Gondwana basins of India such as Umrer and Kamthi coalfields and Godavari, Damodar, Son-Mahanadi and Satpura basins. It can also be tentatively correlated with the early Permian palynoassemblages ofo South America, Antarctica, Australia, Africa and Salt range of Pakistan. Hence, Artinskian and Kungurian age (early Permian) has been assigned to the studied palynoassemblages respectively.The study of organic matter has revealed three distinct palynofacies (I-III) which are characterized by the dominance of palynomorphs (Palynofacies-I), phytoclasts (Palynofacies-II) and biodegraded organic matter (Palynofacies-III) respectively. Palynofacies-I-III reflects the proximal fresh water settings; oxidizing fluvio-deltaic near shore conditions and distal dysoxic waterlogged settings respectively. Palynofacies-I and II represent the oxidizing conditions while Palynofacies-III represents the reducing conditions. [ABSTRACT FROM AUTHOR]

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]

Palynofloras have been recorded from the Barakar Formation in the Borehole MBKW-3, Barpali-Karmitikra Block, Mand-Raigarh Coalfield, Chhattisgarh. Three distinct palynoassemblages have been identified and referred to the following palynoassemblage zones - Gondisporites raniganjensis (Latest Permian); Faunipollenites varius (latest Early Permian), and Scheuringipollenites barakarensis (late Early Permian). It is inferred that these deposits contain the representative palynoassamblages of Early to Late Permian in age. The First Appearance Datum (FAD)s of Arcuatipollenites pellucidus, A. ovatus, Guttulapollenites hannonicus, Lundbladispora microconata, Alisporites opii, Klausipollenites sp., and Goubinispora indica (at 41.95, 45.90, 98.35 m depth), indicate the closing phase of Permian, as these elements are the key species that mark a transition from Permian to the Lower Triassic. An attempt has been made here to reconstruct the phytogeographical provincialism on the basis of Guttulapollenites recorded in this basin. [ABSTRACT FROM AUTHOR]

The palynostratigraphic data given here are based on the explored borecores (TRBD-2, TRBD-3 and TROD-1), by Geological Survey of India. The Permian strata worked-out is about 1174.00 m thick and comprises from base to top - Talchir, Barakar and Barren Measures formations. The palynological content enables delimitation of five palynological assemblages. (i) Scheuringipollenites barakarensis, (ii) Faunipollenites varius, (iii) Gondisporites raniganjensis, (iv) Densipollenites magnicorpus, and (v) Krempipollenites indicus in ascending order from the subsuface rock strata. The lithologically identified strata Talchir Formation in borecores TRBD-2 and TRBD-3 is palynologically dated late Early Permian in having the Scheuringipollenites barakarensis and the Faunipollenites varius palynozones. Subsequently, the part of Barakar strata in these borecores corroborates with Barakar Formation. In borecore TRBD-3, the Barren Measures rocks do not match with the palynological dates, and are affiliated with the palynoflora of the Raniganj Formation. In TROD-1, the strata identified as Barakar Formation is dated Late Permian in having Gondisporites ranigangensis Palynozone; while that of Barren Measures Formation is palynologically dated Early Triassic having Krempipollenites indicus Palynozone. The palynology has helped in the precise dating of the Lower Gondwana succession of Odari and Bartikhurd blocks in Tatapani-Ramkola Coalfield of South Rewa Gondwana Basin. [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]