• Anju Saxena

      Articles written in Journal of Earth System Science

    • Permian macro- and miofloral diversity, palynodating and palaeoclimate implications deduced from the coal-bearing sequences of Singrauli coalfield, Son–Mahanadi Basin, central India

      Kamal Jeet Singh Srikanta Murthy Anju Saxena Husain Shabbar

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      The coal-bearing sequences of Barakar and Raniganj formations exposed in Bina and Jhingurdah open-cast collieries, respectively, are analysed for their macro- and miofloral content. The sediment successions primarily comprise of sandstones, shales, claystones and coal seams. In addition to the diverseglossopterid assemblage, four palynoassemblage zones, namely Zones I and II in Bina Colliery and Zones III and IV in Jhingurdah Colliery, have also been recorded in the present study. The megafossil assemblage from the Barakar strata of Bina Colliery comprises of three genera, namely Gangamopteris, Glossopterisand cf. Noeggerathiopsis. Palynoassemblage-I is characterised by the dominance of non-striate bisaccate pollen genus Scheuringipollenites and subdominance of striate bisaccate Faunipollenites and infers these strata to be of Early Permian (Artinskian) age (Lower Barakar Formation). The palynoassemblagehas also yielded a large number of naked fossil spore tetrads, which is the first record of spore tetrads from any Artinskian strata in the world and has a significant bearing on the climatic conditions. The palynoassemblage-II is characterised with the dominance of Faunipollenites over Scheuringipollenites and is indicative of Kungurian age (Upper Barakar Formation). The megafossil assemblage from the Raniganj Formation of Jhingurdah Colliery comprises of five genera with 26 species representing four orders, viz., Equisetales, Cordaitales, Cycadales and Glossopteridales. The order Glossopteridales is highly diversifiedwith 23 taxa and the genus Glossopteris, with 22 species, dominates the flora. The mioflora of this colliery is represented by two distinct palynoassemblages. The palynoassemblage-III is correlatable with the palynoflora of Early Permian (Artinskian) Lower Barakar Formation. The assemblage suggests thecontinuity of older biozones into the younger ones. The palynoassemblage-IV equates the beds with composition V: Striatopodocarpites–Faunipollenites–Gondisporites assemblage zone of Tiwari and Tripathi (1992) of Late Permian (Lopingian) Raniganj Formation in Damodar Basin. The FAD’s of Alisporites,Klausipollenites, Falcisporites, Arcuatipollenites pellucidus and Playfordiaspora cancellosa palynotaxa in this assemblage enhance the end Permian level of the Jhingurdah Top seam, as these elements are the key species to mark the transition of Permian into the Lower Triassic.

    • Early Permian macrofloral diversity in Indian Gondwana: Evidence from Talchir Formation of Singrauli coalfield, Son–Mahanadi valley basin, central India

      ANJU SAXENA MD MERAJUDDIN KHAN NILASREE RAYCHOWDHURY K J SINGH

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      The flora of Early Permian Talchir Formation is very significant as it holds evidence for the appearance of altogether new Cora, the ‘Glossopteris flora’. This study contributes to our current understanding of Talchir flora. It also reveals a poor diversity of macrofloral assemblage recorded from the Lower Permian sediments of non-coaliferous Talchir Formation from Singrauli coalfield, Son–Mahanadi valley basin. Recovered plant assemblage is characterised by the occurrence of mostly leaf forms namely, Cordaitales (Euryphyllum), Glossopteridales (Gangamopteris, Palaeovittaria and Cordaicarpus) and Coniferales (Paranocladus) along with stem casts/impressions. Flora is marked with the abundance of the genus Gangamopteris with five species, followed by genus Euryphyllum with four species. The present macroflora is broadly similar to other known contemporaneous Coral records of India and other Gondwanan continents but the lack of the genus Noeggerathiopsis in the present assemblage makes it distinct. Genera Euryphyllum (E. elongatum, E. obovatum and E. whittianum) and Palaeovittaria (P. kurtzii) along with taxon Gangamopteris rajaensis, are being reported for the first time from the Talchir Formation of India. Based on the present macrofloral records, the studied sediments have been corroborated to be of Early Permian (Sakmarian) age when the climate was still cold.

      $\bf{Highlights}$

      $\bullet$ Euryphyllum, Palaeovittaria and taxon Gangamopteris rajaensis are reported for the first time from Talchir Formation of India.

      $\bullet$ Insightful interpretation of Early Permian (Sakmarian) megaflora of Talchir Formation from Singrauli basin and its distribution in other Gondwana basins of India.

      $\bullet$ The flora is co-relatable with the ‘middle floristic zone’ of Talchir flora when the climate was still cold, though not harsh.

      $\bullet$ Represents correlation of Talchir flora of India with contemporaneous flora of other Gondwana continents.

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