CHARACTERIZATION OF BEHAVIORAL COMPLEXITY IN MARINE TRACE FOSSILS AND ITS PALEOENVIRONMENTAL SIGNIFICANCE: A CASE STUDY OF ZOOPHYCOS

The paleoenvironment influences trace-making behavior significantly, and progressively more evidence shows that this behavior follows scale-invariance properties. In this study, we focused on the definition of behavioral complexity in the trace fossil Zoophycos to explore its paleoenvironmental significance. Firstly, the fractal topography in Zoophycos was established by introducing virtual tertiary lamellae. Next, a fractal dimension (D) model was proposed and the spatio-temporal evolution trend of the complexity of the trace-making behavior was established. In application, the correlation of D to the paleo-water depth and substrate consistency of the paleoenvironment was analyzed with the aid of variations of delta C-13 and lamellae deformations in Zoophycos from the Carboniferous-Permian Taiyuan Formation of North China. The results show that D increases with paleo-water depth, although it decreases when the degree of substrate consistency increases. Our investigation indicates that fractal topography not only provides an essential explanation for the complexity of trace-making behavior but also plays a reliable and significant role in paleoenvironmental interpretation. Most importantly, this work may shed some light on the subject of fractal ichnology and provide a mathematical framework toward studies in quantitative ichnology.

Automated summary

The study established fractal topography in Zoophycos and proposed a fractal dimension (D) model, analyzing the correlation of D with paleo-water depth and substrate consistency. The results showed that D increases with paleo-water depth, but decreases when substrate consistency increases.