Trace Fossil Thalassinoides and its paleoenvironmental factors of Cambrian in Henan Province

Key words: 
• Cambrian /
• carbonate platform /
• bioturbation /
• depositional environment

Abstract: [Objective] A large number of trace fossils Thalassinoides developed in the Cambrian, Henan Province. By studying the morphology and distribution characteristics of different ichnospecies and analyzing their sedimentary environment controlling factors. [Methods] Based on lithology and ichnography, the morphology, size, disturbance depth and disturbance intensity of Thalassinoides in this area were combined with sedimentary environment parameters. [Results and Discussions] The dense network Thalassinoides suevicus features Y-shaped branches with enlarged intersections, develops in the intertidal zone where water is turbulent and oxygen is abundant.Sparse Thalassionides horizontalis Type 1, which is Y-shaped long branches with large diameters, is formed in the shallow water area in front of the oolitic beach with abundant oxygen and nutrients due to water turbulence. Thalassionides horizontalis Type 2, T-shaped short branches with smaller diamerters, occurs in deeper waters on the seaward side in front of the oolitic beach. The three-dimensional, boxed burrows of Thalassionides bacae, featuring vertical tubes, branches, and thick lining walls, developed in interbeach-confined seas and deep subtidal zones where oxygen and nutrients were deficient. [Conclusions] The variation in different ichnospecies and morphologies of Thalassinoides is controlled by factors such as water depth, water kinetic energy, nutrients and oxygen content of the sedimentary environment. The trace maker adopted different strategies to cope with the changing sedimentary environment.