Geometric tests and their application to fault-related folds in Kuqa

Abstract

For brittle rock deformation, there are two main types of fault-related folds found in foreland thrust belts, i.e. fault-bend folds and fault-propagation folds. The predicted angular function for the quantitative geometric relationships between fault shapes and fold shapes in fault-bend folds and fault-propagation folds have been tested in seismic profiles; i.e. Deep Bashijiqike, Tugeerming, Kashangtokai, East Qiulitage, Deep East Qiulitage and Yakelike fault bend anticlines and Bashijiqike, Yiqikelike and South Yiqikelike fault propagation anticlines in the Kuqa rejuvenated foreland thrust belt. Test results for the transformation from seismic-time section into seismic-depth section using the seismic velocity spectrum can be used to identify whether the interpreted structures are reasonable. With geometric analysis and testing of the subsurface structures, it is possible to predict the existence of the fault-bend folds and fault-propagation folds in the Kuqa area. This study provides convincing proof that the Kuqa basin is a rejuvenated foreland basin.