Earliest freshwater diatoms from the deccan intertrappean (Maastrichtian) sediments of India

We recovered freshwater diatoms from the Maastrichtian lacustrine intertrappean beds, intercalated between the Deccan lava flows, exposed near the village Naskal, Andhra Pradesh, India. The diatoms were recovered from rhizopod (Thecamoeba) cysts assigned to Nitzschia and Planothidium. Other, unidentifiable diatoms are also present in the collections examined. Based on the modern ecological affinities of these diatoms, it is inferred that the sediments were deposited in a freshwater bog or mire, perhaps a small pond where water was circumneutral to slightly acidic. Spores of freshwater ferns dominate the assemblage, which also supports the above inference. Associated marker palynomorphs, namely Ariadnaesporites, Gabonisporites, Triporoletes, Mulleripollis, Azolla and Minerisporites corroborate the Maastrichtian age based on paleontological studies. Presence of ferns and fungal remains in the assemblage reflect warm and humid conditions prevailing during the period of deposition of the sediments.