Permian palynostratigraphy and palaeoclimate of Lingala–Koyagudem coalbelt, Godavari Graben, Andhra Pradesh, India

Godavari Graben, one of the biggest basins among several Gondwana basins of India, holds a unique position not only because of its geographical location in South India, but also due to the presence of almost complete succession from Permian to Cretaceous sediments. The Graben is traversed by many small faults due to which the dating and correlation of coal bearing horizons is difficult in this area. As palynology is one of the most reliable parameter for dating, correlation and characterization of continental deposits, palynological studies have been carried out in order to date and correlate the coal bearing horizons of Gundala, Mamakannu and Kachinapalli areas from Lingala–Koyagudem coalbelt of Godavari Graben.The distributional pattern of various palynotaxa has suggested the occurrence of eight distinct palynozones in five borecores of Gundala (MLG-23, MLG-24, and MLG-28), Mamakannu (MMK-19) and Kachinapalli (MGK-6) areas. These palynozones are comparable to Talchir, Lower Karharbari, Upper Karharbari, Barakar and Raniganj palynoflora of Indian Lower Gondwana. Palynozone-1 is equivalent to Parasaccites Assemblage of Talchir Palynoflora; Palynozone-2 is correlatable with Callumispora + Parasaccites Assemblage of Lower Karharbari palynoflora; Palynozone-3 corresponds well with Parasaccites + Scheuringipollenites Assemblage of Upper Karharbari palynoflora; Palynozone-4 is comparable to Scheuringipollenites Assemblage of Barakar palynoflora; Palynozone-5 is correlatable with Faunipollenites + Striatopodocarpites Assemblage of Raniganj palynoflora; Palynozone-6 is comparable with Striasulcites Assemblage of Raniganj palynoflora; Palynozone-7 shows its equivalence with Parasaccites Assemblage of Raniganj palynoflora and Palynozone-8 corresponds well with the Crescentipollenites Assemblage of Raniganj palynoflora. On the basis of palynofloral evidences, it has been suggested that palaeoclimate during Palynozone 1–3 was cool but humidity was more in Palynozone-3 in comparison to Palynozone-2. Warmer phase started during Palynozone-4 with thick coal deposits, while Palynozones 5–8 representing Raniganj palynoflora indicate warm climate with very high humidity.

► Palynologically Talchir–Raniganj palynoflora has been recognized in this study.
► Barren Measures palynoflora has not been recorded in any borecore.
► Existence of two coal bearing horizons has been indicated.
► High percentage of Parasaccites along with striate disaccates has been marked.
► Study reveals the cool to warm palaeoclimate with the fluctuating humidity.