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在林西地区新发现的叶肢介和介形虫等化石，证实了大兴安岭南部存在早三叠世地层。这套地层为具有红层性质的河—湖环境产物，与下伏上二叠统林西组沉积有较大的差异。林西组中—下部以海相沉积为主，并发育浊流沉积，反映直到晚二叠世中期大兴安岭南部仍有残余海盆存在，应是造成晚二叠世南北植物化石仍保持区系特征的主因。林西地区晚二叠世—早三叠世的沉积—构造演化特征揭示，大兴安岭南部的晚古生代板块构造活动一直到印支构造旋回才结束。
Newly found fossils such as leaf-limbs and ostracods in the Linxi area confirm the existence of the Early Triassic strata in the southern part of the Greater Xing’an Mountains. This set of strata is a river-lake environment product with red beds, which is quite different from the sediments of the Lower Permian Linxi Formation. The middle and lower parts of the Linxi Formation are dominated by marine sediments and developed turbidite sediments. It is not until the late Late Permian that there are still residual basins in the southern part of the Greater Xing’an Mountains, which should result in the fossil remains in the Late Permian The main reason. Late Permian-Early Triassic sedimentary-tectonic evolution in the western Linxi area revealed that the Late Paleozoic tectonic activity in the southern part of the Greater Hinggan Mountains did not end until the Indo-China structure was cycled.