摘要
为了研究双层滑脱构造变形的主控因素,设计了3类砂箱模型,对滑脱层材料、滑脱层厚度、滑脱层黏度、上覆砂层厚度、受力边界条件等主控因素进行物理模拟试验研究。试验结果表明:不同滑脱层材料产生的变形样式不同。以微玻璃珠组成的滑脱层主要产生前展型逆冲叠瓦式断裂构造,下部滑脱层起主控滑脱作用,上部滑脱层厚度、滑脱层之上砂层厚度越大越容易形成滑脱断层;挤压方向与受力边界间的夹角较大时,上部滑脱层容易先形成滑脱断层,其推覆体前缘水平位移较快。以不同黏度硅胶组成的滑脱层产生不同的分层滑脱构造变形样式,当下部滑脱层硅胶黏度为500～1 000Pa.s时,形成分层滑脱前展型叠瓦式构造;当硅胶黏度为2 000～2 500Pa.s时,靠近挤压端先形成背冲构造,然后在上部滑脱层形成叠瓦式构造,在下部滑脱层形成对冲三角带构造、冲起背斜构造。地震和钻井资料显示,准噶尔盆地南缘西段霍尔果斯—安集海褶皱冲断带具有双层滑脱变形特征;模拟结果认为,斜向受力边界、侏罗纪煤层以及古近纪泥岩层的分层滑脱作用是控制变形过程的主要因素。
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.
出处
《地球科学与环境学报》
CAS
2012年第2期15-23,共9页
Journal of Earth Sciences and Environment
基金
国家自然科学基金项目(40972091)
关键词
双层滑脱构造
褶皱冲断带
变形特征
主控因素
物理模拟
砂箱模型
霍尔果斯—安集海
准噶尔盆地
double decollements
fold-and-thrust belt
deformation characteristic
maincontrolling factor
physical simulation
sand-box model
Khorgos-Anjihai
Junggar Basin
