The late Ordovician-early Silurian transition witnessed extinctions, eustatic changes, climatic fluctuations, frequent volcanism, large-scale glaciation, intense tectonic activities, changes in oceanic redox, accompanied by the shale deposition on a global scale (Bond & Grasby, 2020;Hu et al., 2020;Vandenbroucke et al., 2015). The late Ordovician-early Silurian shale is regarded as the source rocks and reservoirs for shale gas, and commercial oil and gas exploration and production have been achieved in some areas such as the Wufeng-Longmaxi Formations shale in the upper Yangtze Block, South China (Zou et al., 2019), and the hot shales in North Africa and Arabia (Lüning et al., 2000). Organic matter can provide adsorption space, and organic pores created by the corrosion of organic acid, and can generate hydrocarbons for shale gas accumulation (

The Tibetan Plateau is ascribed to high-elevation (average elevation >4,000 m above sea level) and cold climatic conditions (mean annual air temperature <4°C), the ecological environment is fragile, and there are fiercer responses to climatic variability than most regions on the Earth (