Cretaceous age for Ir-rich Deccan intertrappean deposits: palaeontological evidence from Anjar, western India

Abstract

Micropalaeontological investigations of an iridium-bearing, lacustrine intertrappean sedimentary sequence at the western margin of the Deccan volcanic province near Anjar, have revealed a profuse occurrence of theropod eggshell fragments (ornithoid type) in beds overlying the iridium-enriched levels. Associated late Cretaceous ostracods, lack of evidence of reworking, and the absence of any exclusively Palaeocene taxa above the iridium levels, taken together, indicate that the extinction of dinosaurs in the Indian subcontinent occurred after the deposition of Ir layers at Anjar, and that these Ir anomalies may significantly predate the K-T boundary.