Physical Simulation of Double Decollements. Insights into the Fold-and-thrust Belt in the Southern Front of Junggar Basin

详细信息   

• 责任者：Yu Fusheng (State Key Laboratory of Petroleum Resource and Prospecting ; China University of Petroleum ; Beijing 102249 ; China) ; Li Dinghua
• 刊名：Journal of Earth Sciences and Environment
• 出版年：2012
• 卷期：34(2)
• 关键词：滑脱构造 ; decollement ; 因素 ; factors ; 准噶尔盆地 ; Junggar Basin
• 页码：p.15-23
• 图表：illus., 2 tables, 40 refs.
• 分类号：1200
• issnNo：ISSN1672-6561
• isbnNo：CN61-1423/P

摘要

In order to study the main controlling factors of deformation generated by double decollements, three sets of sand-box models were devised to physically simulate the main controlling factors including the material for double decollements, thickness and viscosity of double decollements, thickness of overlying sand and stress boundary condition. The test results showed that different materials for double decollements produced different sets of structure styles. Imbricate wedges thrusting forward were developed and governed by the lower decollement made up of micro glass beads, the more thickness of upper decollement and overlying sand above the decollement consisted of micro glass heads were, the easier detachment fault developed, and the larger included angle between compression direction and stress boundary was, the easier to generate detachment fault along upper decollement with faster horizontal migration of thrust wedge. Different structure deformation patterns with lamination formed above viscous decollements consisted of silicon gels with different viscosities, and when the viscosities of silicon gels for lower decollement were 500～1 000 Pa·s, imbricate wedges thrusting forward with lamination developed, and when the viscosities of silicon gels were 2 000～2 500 Pa·s, pop-up structure nearby the compression end developed first, then imbricate structure formed within upper decollement, and trigonometric belt, pop-up structure and basement involved anticline developed within lower decollement. Seismic profile and drilling data indicated that fold-and-thrust belts in Khorgos-Anjihai in the western part of southern front of Junggar Basin had the lamination deformation characteristics generated by double decollements, and the simulation results illustrated that the lamination decollement of oblique stress boundary, coal layer in Jurassic and mudstone bed in Paleogene were the main controlling factors on deformation.