The geological age and paleoenvironment of Baby Louie-bearing strata

"Baby Louie" dinosaur fossil embryo, located at the bottom of Upper Cretaceous Gaogou Formation in Xixia Basin, was excavated from Zhaoying Village of Yangcheng Township in Xixia County of Nanyang City, Henan Province. Upper Cretaceous strata of Xixia Basin can be divided from bottom to top into Gaogou Formation, Majiacun Formation and Sigou Formation. "Baby Louie" is embryonic skeleton fossil of Macroelongatoolithus xixaensis. Gaogou Formation is rich in dinosaur egg fossils and little dinosaur bone fossils as well as a few fossil fragments of bivalve, gastropods, Ostracods, Charophyceae, plant pollen, and plant fossil together with abundant trace fossils. According to geological age of fossils in combination with conformable contact between Majiacun Formation and Gaogou Formation as well as fossil assemblage of Sigou Formation, angular contact between Gaogou Formation and Lower Devonian Nanwan Formation and stratigraphic correlation with surrounding basin layers, the authors hold that geological epoch of Gaogou Formation in Xixia Basin should be Late Cretaceous Coniacian. The lower and middle Gaogou Formation seems to be terrigenous clastic rocks of semi-arid red continental type molasse-like formation belonging to alluvial fan and braided river sedimentation of intermittent muddy waters, whereas the upper part of Gaogou Formation seems to be alluvial fan and traction current deposit. The horizontal paleo-geographic environment of "Baby Louie" is flat and wide alluvial fan facing south at the alluvial end, which can be classified as alluvial fan facies-fan end subfacies-flowing microfacies.