The trace fossils and their sedimentary environments in the Cretaceous Jiaguan Formation, Qijiang, Chongqing

The trace fossils are mostly autochthonously buried, and so it is significant to study the trace fossils for the reconstruction of palaeoenvironments, palaeoclimatology, palaeoceanography and palaeoecology. The present paper gives a detailed description of the types and sedimentary environments of the trace fossils, and may provide new trace fossil evidence for the sedimentary evolution of the Jiaguan Formation in Qijiang, Chongqing. The trace fossils examined in this study occur in the strata of the Cretaceous Jiaguan Formation in the Laoyingshan scenic area of the Qijiang National Geological Park, Qijiang, Chongqing, and consist of one ichnofacies, three ichnogenus and three ichnospecies i. e., Scoyenia gracilis, Beconites antarcticus and Planolites beverleyensis. These trace fossils are assigned to the Scoyenia ichnofacies and represent the flood plain or littoral-shallow lake environments which are intermittently exposed to the surface in the deposition of the the Jiaguan Formation during the Cretaceous.