Abstract
The basin marginal fault system is the key to understand the formation and evolution of Songliao Basin. In order to investigate the influence of marginal fault system on the structural evolution of Songliao Basin, a comprehensive study was conducted on Shiling Town and Zhuanshanhu area of Yehe Town in Siping City of Jilin Province, where is the southeastern margin of the Songliao Basin and there are a series of well-exposed fault, fold and intrusive bodies belonging to the main marginal fault system of the Songliao Basin known as the Jiamusi-Yitong(Jia-Yi) fault zone. Through profile measurement and field investigation, samples with various lithologies and distinctive features were collected. Detailed field and laboratory works include component and microstructure analysis of these samples, rock-rock contact analysis, main strike measurement and statistics analysis. These data reveal the structural characteristics of the fold, fault and intrusive bodies in the study area. The research results show that the folds are distributed in the Mesozoic strata near the main fault of the eastern branch of the Jia-Yi fault zone, and the folded strata involve the Cretaceous Denglouku and Quantou formations. In addition, the section is dominated by high-angle strikeslip thrust faults. Light-colored veins and dark-colored veins are extensively distributed in the exposed granites. Statistical analysis of joint and fault attitudes in the study area reveals a right-lateral strike-sliping along the main fault. The large-scale right-lateral strike-slip and thrust fault system in Shiling Town occurred in right-lateral transpressive stage in Late Cretaceous. Based on the results above, tectonic evolution sequence in Shiling section of the Jia-Yi fault zone during the Mesozoic can be divided into five stages: Middle Jurassic left-lateral ductile strike-slip stage, Late Jurassic compression stage, Early Cretaceous tension stage, Early Cretaceous extension stage and Late Cretaceous right-lateral transpressive stage. These may have important constraint on understanding the Mesozoic evolution of the Songliao Basin.
