关键词: 青藏高原东缘, 物理模拟, 龙日坝断裂带, 龙门山断裂带, 碧口块体

Abstract: In the eastern part of Songpan-Ganzi block about 150 km northwest of Longmenshan fault zone in the eastern Tibetan Plateau, there is a NE-trending Longriba fault zone featured with dextral transpressive shearing. Due to its special geographical location, it has attracted widespread attention. In order to study the relationship between these two similar fault zones, three groups of physical analogue modeling are designed according to the actual geological conditions of the region and the similarity principles. The influence of the Bikou terrane and the bottom detachment is mainly considered, and the Particle Image Velocimetry is used to monitor the surface deformation. The experimental model shows that NE-trending Longmenshan fault zone and Longriba fault zone with thrust and right-lateral strike-slip component and Minshan uplift zone with north-south strike are developed under EW compression stress. According to the experimental results, we conclude that only with the existence of the Bikou terrane, faults develop along the boundary of the detachment, otherwise arc faults develop within the detachment layer. The Longmenshan fault zone is connected with the Longriba fault zone in the deep detachment to form a pop-up structure.The results of this study show the development process of fault zone under the influence of Bikou terrane, and provide a possible structural model for understanding the relationship between Longmenshan fault zone and Longriba fault zone.

Key words: eastern Tibetan Plateau, analogue modeling, Longmenshan fault zone, Longriba fault zone, Bikou terrane