豫西济源地区中下三叠统遗迹网络分析

豫西济源地区下三叠统和尚沟组和中三叠统二马营组均为陆相河湖相沉积，本研究在和尚沟组和上覆二马营组中下段分别识别出遗迹化石5属6种和7属9种，这些化石材料成为探究大灭绝事件后陆地造迹生物复苏的良好材料。运用遗迹网络分析方法构建了和尚沟组和二马营组中下段遗迹网络，相关参数显示自早三叠世和尚沟组沉积期至中三叠世二马营组中下段沉积期，遗迹网络节点增加，平均度、平均加权度和图密度有所降低，网络直径、平均聚类系数和平均路径长度呈明显增加趋势，遗迹网络复杂化以及造迹生物对恶劣环境适应性的增强，这些可能是二叠纪—三叠纪之交灭绝事件(Permian-Triassic Mass Extinction, PTME)后生物复苏的潜在标志。推测PTME后华北地区生物复苏和生态恢复可能遵循着类似的模式，但后续研究仍需陆相实体化石证据的佐证与补充。

Ichnonetwork analysis of the Lower-Middle Triassic in Jiyuan area,western Henan Province

The Lower Triassic Heshanggou Formation and Middle Triassic Ermaying Formation in western Henan Province represent terrestrial fluvial-lacustrine deposits. Six ichnospecies/five ichnogenera and nine ichnospecies/seven ichnogenera have been identified in the Heshanggou Formation and the lower-middle members of the Ermaying Formation in the Jiyuan area respectively. Based on ichnonetwork analysis,the ichnonetwork of the Heshanggou Formation and the lower-middle members of the Ermaying Formation was constructed to explore the variety of benthic metazoan after the Permian-Triassic Mass Extinction(PTME). The analysis of ichnonetwork shows that during the depositional period of the Heshanggou Formation to the lower-middle members of the Ermaying Formation,the number of nodes,the diameter,the average clustering coefficient and average path length of the ichnonetwork increase significantly. However,the average degree,average weighting degree and density of the ichnonetwork decrease slightly. The complexity of the ichnonetwork and the enhancement of the adaptability of trace makers to harsh environments of the Early and Middle Triassic ichnonetwork has become a potential sign of biological recovery after the mass extinction. Combined with previous studies,the biological recovery and ecological recovery after PTME may follow the similar pattern in North China, though this pattern still need to be corroborated and supplemented by the follow-up studies with more fossil evidences.