Vertebrate Fauna From the Infra- and Inter-trappean Beds of Andhra Pradesh: Age Implications

Investigations on the infra- and inter-trappean beds exposed at Asifabad, Naskal, Marepalli, and Timsanpalli, Andhra Pradesh, have resulted in the discovery of a large number of microvertebrate remains represented by scales, teeth and other postcranial elements of fishes, amphibians, reptiles, and mammals. A remarkable similarity exists between the fauna of infra- and inter-trappean beds indicating a short interval of time for the deposition of these sediments. In these-non-marine sequences across the CTB, there are relatively few well-known markers to delineate the Cretaceous strata from the Tertiary among which batoid and holostean fishes, dinosaurs, and primitive palaeoryctid mammals are important. The fishes, dinosaurs and mammals strongly support Late Cretaceous and latest Cretaceous ages for the infra- and inter-trappean sequences respectively. The vertebrate evidence is in agreement with the palaeomagnetic and radiometric datings which suggest a late Cretaceous initiation and a very short duration for the eruption of Deccan volcanics.