Stratigraphic and sedimentary facies analysis of the Penglaizhen Formation in the Ya'an-Danling region, Sichuan

The present paper gives a detailed description of the measured stratigraphic sections of the Penglaizhen Formation in the Ya'an-Danling region, Sichuan, with the emphasis on the lithostratigraphy and sedimentary facies associations and horizontal variations in lithology and sedimentary facies. The Penglaizhen Formation is made up of the lake facies and lake-delta facies, and two long-term and five medium-term base-level cyclic sequences in which individual sequences and systems tracts are elucidated. The establishment of the assemblage zone Porochara maedleri-Aclistochara yunnanensis in the strata of the Penglaizhen Formation indicates a Late Jurassic age for the deposition of the Penglaizhen Formation.