On the occurrence of Campanian rudist biostrome, Aruma Formation, Central Saudi Arabia

The lower limestone Khanasir Member of the Aruma Formation in central Saudi Arabia is characterized by Campanian rudist biostrome at its uppermost part. The most abundant rudist fauna are Eodictyoptychus arumaensis, Durania sp. and Biradiolites sp. Succession is overlying continental siliciclastics of Wasia Formation and comprises shale at the base followed by slightly dolomitized, burrow, nodular limestone and caps with rudist biostrome. Abundant microfacies types are wackestones, packstones, grainstones and floatstones with green algae, benthic foraminifers. The succession in general, indicated shallowing upward sequence and rudist biostrome represents a shallow marine lagoonal environment.