Stratigraphy, sedimentology and palaeoecology of the dinosaur-bearing Cretaceous strata at Dashuiguo (Inner Mongolia, People's Republic China)

The stratigraphy and the sedimentology of the Cretaceous continental dinosaur-bearing strata of the Dashuiguo area have been investigated. A 100 m thick local lithostratigraphic column has been established. It consists of several fining upwards sequences composed of nine lithofacies representing the different sedimentary environments within an alluvial plain. The dinosaur bones are accumulated in bone beds that form the basal lag within the fossil channels (lithofacies Ss). Numerous isolated bones have been retrieved fromm the cross-bedded sandy infill of those channels. The fossil alluvial river has its source within the nearby Hanwulan Shan that are the source of the sediment load in this river. Based on charophytan evidence the sediments have been attributed to the upper Lower Cretaceous (Barremian-Albian). The paleoclimate is described as a subhumid climate with seasonal dry periods considering the soil type, the fossil fauna and flora and the presence of satin spar veins and evaporitic crystals.