A Diverse Microfossil Assemblage from the Ediacaran–Cambrian Deep-Water Chert of the Liuchapo Formation in Guizhou Province, South China

The Ediacaran to Cambrian transition witnessed great biological and environmental turnovers from the Precambrian to Phanerozoic. These changes are also reflected by the fossil records during that time. However, the fossil distribution was highly heterogenous. While diverse fossils were constantly found from the shallow shelf including restricted basins, reports from deep-water areas, which are characterized by chert-dominated formations straddling the Ediacaran-Cambrian boundary, were scarce. Among them was the Liuchapo Formation that has been considered barren. In this study, a fossiliferous assemblage was found from the Liuchapo Formation in east Guizhou Province, South China. This assemblage comprises Palaeopascichnus jiumenensis, Horodyskia minor, multicellular algae that possibly related with red algae, cyanobacteria, sponge spicules, small shelly fossils, membrane structures of uncertain affinity, and fossils with structures resemble the Ediacaran Megasphaera. Palaeopascichnus and Horodyskia have been widely reported and abundant in the Liuchapo Formation and equivalents, while the others have seldomly, or never, been found from this formation or, more widely, the deep-water chert of transitional interval. The discovery not only contributes to the rare paleontological records preserved in deep-water sediments, but also expanded the geographic distribution of the fossils, providing new materials of biological diversity during this critical interval.