The basin and range systems and their evolution of the northwestern margin of Junggar Basin, China: Implications for the hydrocarbon accumulation

摘要

Basin and range system in the northwestern margin of the Junggar Basin highly controlled the distribution of sediments and oil and gas. Detailed studies of basin and range system will be helpful in understanding the formation of hydrocarbon resources. Based on the previous studies and geophysical data, we analyze the structural characteristics and their evolution of basin and range system in this area. Although the basement of the Junggar Basin is still uncertain, high resolution of geophysical data suggests that the basement of the basin generally has lower and much stable gravity and magnetic anomalies than that in the orogenic belts around the basin and these anomalies are uneven in the basin, implying the basement may be assembled by different blocks. The amalgamation of these blocks will affect the deformation of the corresponding sedimentary cover. Detailed seismic interpretation across the basin and range system suggest that the imbricate thrust faults are dominant structural styles in this area. The Zaire-Hala'alate mountains were raised after multi-stage tectonic movement, and they started to rise in Late Carboniferous. The evolution of the western margin of the Junggar Basin can be divided into three stages, which are the initial formation stage in Late Carboniferous, the foreland basin developed stage from Permian to Jurassic and the rejuvenated foreland basin stage in Cenozoic. The coupling processes of basin and range system caused the formation, migration, and accumulation of the hydrocarbon resources both in space and time in the northwestern margin of the Junggar Basin.