Palaeontological and sedimentological observations on nonmarine Lameta Formation (Upper Cretaceous) of Maharashtra, India: their palaeoecological and palaeoenvironmental significance

Abstract

The Lameta Formation (Upper Cretaceous) is exposed in parts of central and western India as detached outcrops and covers an area of nearly 5000 km 2. It generally rests on Precambrian and “Gondwana” rocks and is invariably capped by Deccan Trap volcanic flows. In the Nand and Dongargaon areas of the Chandrapur and Nagpur districts of Maharashtra, the Lameta Formation covers more than 400 km 2, attains a thickness of 20 m and is richly fossiliferous. The palaeontological and sedimentological observations strongly indicate alluvial-limnic environment for the deposition of the Lameta sediments under semi-arid conditions. Different lithofacies representing channel, overbank, paludal and lacustrine subenvironments have been identified. The biota represents terrestrial, semiaquatic and aquatic communities and is represented by dinosaurs, fishes, crocodiles, chelonia, gastropods, ostracodes, charophytes, coniferales and angiosperms. The biota appears to be mainly controlled by the different lithofacies, thereby suggesting strong palaeoecological and taphonomical control over their occurrence. Records of mass death of clupeids have been observed in many layers within the lacustrine clays. A nesting site of sauropods has been found near Pavna along with evidence of site-fidelity. A clutch with small oblong-shaped eggs of avian-like affinity has been also unearthed from this nesting site. The Lameta sediments were deposited in a freshwater environment that provided the preferred ecological niche for large-scale breeding and nesting of sauropods.