1991-92 - Birbal Sahni Institute of Palaeobotany

een recorded from the Cudapah Basin. Digitate stromatolites show varicd types ofmicrostructures from filamentous to rugged nature indicating the role of coccoidand filamentous cyanobacteria in development of the respective microstructure.The ginkgopsid and glossopterid association in the flora from the Datum fircclayquarry of Auranga Coalfield suggests similarity with the ginkgopsid richassemblage of the Lower Permian sediments of Rajmahal Hills, Bihar. Studies onevolutionary lineages in various leaf forms and fructifications of glossopterid indicatedevelopment of glossopterid group of plants along two different lineages. Anew tripinnately branched fern-like foliage Maheshwariopteris digitata is reportedfrom shales associated with Lalmatia coal seam in the Hura Coalfield, RajmahalBasin. Megafloristic investigation of Khutnashi assemblage has revealed that it isolder than Gilamari and Chunakhal floras. It resembles the flora of 2nd intertrappeanbed at Bhutahapahar, Rajmahal Hills. The Mamal Formation, of thePanjal Group in Kashmir has been redefined.Palynological analysis of bore-hole SPB-18 from Middle Pali sequcnce ncarBurhar arca, Sohagpur Coalfield shows a Late Permian palynoassemblage whichrcveals a closer relation with the assemblage from Raniganj Formation. Presenceof Leiosphaeridia in few samples indicates a probable marine influence in this area.The palynological analysis of samples from 450 m deep bore-hole TCW-25 in thenorthern part of the Talcher Coalfield has revealed the presence of three distinctpalynoassemblages based on FADs, LADs and pattern of species distribution.They are comparable to the marker Assemblage zones identified in Damodar­Rajmahal area. The lowermost assemblage - Parasaccites korbaensis AssemblageZone represents the Upper Talchir, and Scheuringipollenites barakarensis AssemblageZone and Faunipollenites varius Assemblage Zone represent Lower andUpper Barakar, respectively. Based on evolutionary changes in the morphology ofthe pollcn groups, their FADs and LADs, eleven Biohorizons and ten lnvcrval zoneshave been identified through the span of Gondwana sequence. Analysis of data onPermo- Triassic boundary has revealed that there had bcen no mass extinction at thisboundary. It was an cpisode of high turnover. The climatic changes and alterationin geomorphology due to new tectonic-setup at the boundary wcre responsible fora major shift in evolution of palynomorphs. Eight palynoevents h~ve been identifiedalong the latest Permian-earliest Triassic transition and they have been tagged withcomparable palynoevents in various basins of the peninsula. Palynoflora I patternsstudied in bore-holes GS-l,2,3 and 4 from Sattupalli area have shown the presenceof Late Permian palynoassemblages. The assemblage is characterised by the presenceof slriate disaccates.Microconstiluents of the coals from Lalmatia colliery have been estimated tounderstand the ratios between various reactive and non- reactive contents. It hasbeen observed that the coals are rich in trimaccrite and of (mixed) type, indicatinginferior quality for selective utilization. A detailed megascopic study of various coalbands indicates that the Talchir coals are mostly composed of hard dull bands. Theyalso soil the finger due to the presence of fusion at various levels, suggestingfluctuating hydrological conditions in the basin. First authentic record of Botryococcusalga (alginite) from Singrauli coals has been made. A scheme for indexingspontaneous combustion susceptibility of Indian coals and lignites has been pro-(iii)