Megascopic carbonaceous compression fossils from the Neoproterozoic Bhima Basin, Karnataka, South India

Abstract

AbstractAn abundant well-preserved assemblage of annulated carbonaceous compressions and impressions has been recorded from the intra-cratonic argillaceous sedimentary sequence of the Bhima basin in south India. Impressions and carbonaceous compressions recorded in the Hulkal Formation belong to annulated forms similar to the previously reported Sinosabellidites huainanensis, Protoarenicola baiguashanensis and Pararenicola huaiyuanensis from China. This paper discusses the diversity, systematics, affinity, biostratigraphical potential and global significance of these remains. The previously proposed worm-like body fossil affinity for these organisms, based on similarity with the Chinese assemblage, has been reinterpreted as with pre-Ediacaran epibenthic organisms. Fresh investigations of the Indian assemblage of such specimens reveal their close proximity to the algal affinity. The occurrence of global marker events, such as phosphatization, the presence of complicated annulated carbonaceous remains in the Hulkal Formation and the absence of stromatolites in the carbonate sequences of the Bhima basin, collectively indicate a Neoproterozoic, possibly pre-Sturtian age for the Bhima Group.