Palynology of the Baratang Formation, Andaman-Nicobar Islands and the significance of reworked palynomorphs

Abstract

Spores-pollen and dinoflagellate cysts data from five sections of the Baratang Formation (Baratang Island) are analysed. The record of stratigraphic potential forms indicates an Early to Late Eocene age for the recovered assemblages. The palynoassemblages from this Formation are also associated with the reworked palynofossils belonging to Permian, Triassic and Jurassic-Cretaceous ages. The reworked taxa dominate over the poorly represented Eocene palynomorphs and have Gondwanic affinity. A comparison of Tertiary palynoflora of Baratang with Assam and Myanmar demonstrate the presence of some palynotaxa in all the areas but common occurrence of significant taxa such as Retitrisyncolpites, Baculimonocolpites and Lanagiopollis (regularis) shows more close relationship between Andaman and Myanmar flora than Assam. The recycled palynomorphs of Gondwanic affinity have provided valuable clue to locate the source and direction of sediments. Various views relating to provenance of reworked palynomorphs have been analysed on the basis of present data which suggest that Chindwin Basin of Myanmar mainly supplied reworked palynomorphs containing sediments. The palynological, palaeocurrent and lithological evidences do not support the origin of reworked elements from Wharton Basin, Assam Basin or autochthonous (Triassic) sediments.