Palaeoworld ( IF 1.7 ) Pub Date : 2020-06-10 , DOI: 10.1016/j.palwor.2020.06.002 Zhi-Feng Xing , Jia Lin , Yu-Xin Fu , Wei Zheng , Yun-Long Liu , Yong-An Qi
The Permian–Triassic Mass Extinction (PTME) resulted in the most severe loss of life in the history of the earth, both marine and terrestrial ecosystems suffered heavy losses simultaneously, and the biotic recovery process was difficult for both. There are many studies on the timing and pattern of this mass extinction, however, the consistency of the recovery between the marine and terrestrial facies remains controversial. In particular, few metazoans survived and the deposits were dominated by the microbialites during the Early Triassic. The reappearance of the metazoans signified the beginning of the biotic recovery. In this paper, we measured the trace fossils of the Heshanggou Formation in western Henan, North China, which plays an important role in the transformation from the flourishing of the microorganisms to the recovery of metazoans. We quantitatively described the characteristics and measured the diameter, depth, abundance and diversity of the trace fossils. Based on the acquired data, the lower part of the Heshanggou Formation is confined to simple, small, vertical burrows, suggesting that the ecological environment was suitable for the survival of special species. In the middle part, the vertical burrows become deeper, which may be due to the adaptation of organisms to the harsh environment. Disturbance is more intense and the diversity clearly increases in the upper part. Through the increasing bioturbation and diversity of the trace fossils, we found a gradual biotic recovery pattern in the Early Triassic, and the recovery mode is similar to marine ichnofossils in South China.