Neerja Jha

Upper Cisuralian palynology and palaeoclimate of Manuguru area Godavari basin, India and their global correlation

The Permian system of the Palaeozoic Erathem is divided into three series, the Early Permian Cisuralian Series, the Middle Permian Guadalupian Series, and the Late Permian Lopingian Series. The Cisuralian Series encompasses the Asselian to Kungurian stages which constitute the basal part of the Gondwana supersequence I. In India, they are represented lithostratigraphically by the Talchir, Karharbari, and Barakar formations. This paper presents the palynological results from the Barakar Formation of the Upper Cisuralian Series from Manuguru which lies in the southeastern part of the Godavari basin. The succession studied comprises 35 subsurface samples from bore hole 1007 represented by clay, shale, sandstone, and coal. The palynofloras in this sequence have a homogenous composition demonstrating that not many significant floral changes took place through the considered stratigraphic range. The entire sequence is characterized by the dominance of nonstriate bisaccate genus Scheuringipollenites and sub-dominance of striate bisaccate genus Faunipollenites(=Protohaploxypinus). The other pollen genera among the nonstriate bisaccates are Rhizomaspora, Primuspollenites, Ibisporites, and Platysaccus. The striate bisaccates include Striatites, Striatopodocarpites, and Stroterosporites. The taeniate taxa are represented by Lueckisporites and Lunatisporites. The common monosaccate genera include Caheniasaccites, Potoniesporites, and Barakarites. Spores are less common and include Latosporites, Brevitriletes, Horriditriletes, Microbaculispora, and Callumispora. They characterize the palynofloral composition of the Lower Barakar Formation. The correlation of this assemblage with some of the biostratigraphic palynozones proposed previously for the Cisuralian sequences of the Paraná Basin of South America, Kalahari Karoo Basin of South Africa, Ruhuhu Basin of Tanzania, East Africa as well as palynoassemblages from South Victoria Land and Dronning Maud Land, Antarctica and Collie Basin of west Australia point out to their Early Permian (Late Sakmarian–Early Artinskian) age. Palynomorphs such as Botryococcus sp., Tetraporinia sp., Balmeela sp. and Leiosphaeridia sp. are also recorded which suggest that these sediments were deposited during post-glacial near shore, cool and humid environment.

Influence of Palaeoenvironmental Factors on the Encystment of Cretaceous Dinoflagellate Cysts (Ceratiaceae): A Study from Godavari Graben, Southern India

ABSTRACT Muderongia staurota forms with long appendages at the distal end of the apical, lateral and antapical horns have been recovered from the Lower Cretaceous Gangapur Formation of Upper Gondwana sequence from the Chintalapudi Sub-Basin (India). The number of distal appendages reflects the number of plates forming the horns. We include these forms in the new species Muderongia gangapurensis sp. nov. The dinoflagellate cysts recovered suggest a late Berriasian to Valanginian for the lower part and a Hauterivian/Barremian age for the upper part of the studied interval of MJR-11 borehole. Unusual Muderongia and Odontochitina cysts bearing similar long appendages have only occasionally been described or illustrated in the literature from sediments rich in continental organic matter. We suggest that Cretaceous Ceratiaceae bearing such appendages are cysts of thecae that encysted in particular environments, where light, salinity, temperature and chemistry of water masses might have been key to their development. Our conclusion is supported by the high morphological variability of horns in modern Ceratiaceae, which reflects environmental factors. We discuss the plasticity of horns in the fossil record and note that such plasticity is recurring in Ceratiaceae, at least in the Early Cretaceous (145 Ma).

Unusual spheroidal inclusions in Late Permian gymnosperm pollen grains from southern India revisited: evidence of a fungal nature

Abstract Conspicuous spheroidal inclusions are infrequently encountered in saccate gymnosperm pollen grains (e.g. Striatopodocarpites subcircularis, Striatopodocarpites multistriatus, Faunipollenites varius, Ibisporites diplosaccus, Scheuringipollenites maximus, Barakarites indicus) from the Upper Permian (±253–275 Ma) of the Godavari Graben, Andhra Pradesh, India. These structures, which occur singly or in clusters of two to eight in the corpus of the pollen grain, are 15–45 µm in diameter, smooth-walled, and usually translucent; ~30% of the specimens show a pre-formed circular opening in the wall. The biological affinities of the inclusions remain elusive. The interpretation of similar structures from the Raniganj Coalfield (Upper Permian, India) as components of the microgametophyte is implausible for several reasons. Rather, these pollen grains represent highly likely host substrates and habitats for microorganisms, and it is, therefore, probable that the inclusions are the remains of a pollen-colonising organism, perhaps the endobiotic zoosporangia of a chytrid or member in the Hyphochytridiomycota.