柴达木盆地北缘新生代构造变形的物理模拟

文中设计了3种类型的基底收缩挤压砂箱实验模型和一种基底无收缩挤压砂箱实验模型，用于研究柴达木盆地北缘新生代构造的变形机制。实验结果表明，基底收缩挤压模型以反冲断层发育为特色。在双侧对称对冲挤压模型中，正冲和反冲断层的发育程度基本处于均衡状态；在双侧不对称对冲挤压模型中，反冲断层更加发育，尤其在挤压速度较快一侧更加显著；单侧挤压模型中，以反冲断层发育、正冲断层很少为特征。由此表明，基底收缩作用和挤压作用的不对称性促使反冲断层的发育。根据实验结果与实际剖面的对比，笔者认为，基底收缩和不对称挤压是导致该区特殊剖面结构的可能原因，该区新生代构造变形是在基底收缩作用参与下、以祁连山为主的侧向不对称挤压作用的结果。

Physical Modeling of the Cenozoic Deformation in Northern Qaidam Basin

Three types of sandbox models with contractive substrate and one without contractive substrate were employed to study the deformation mechanism of Cenozoic structures in northern Qaidam Basin. The results indicate that the models with contractive substrate are characterized by the development of rearward - vergent thrusts. When the models were compressed from opposite directions, the development of forward - vergent thrusts was similar to that of rearward-vergent thrusts, whereas in the models with asymmetric compression the rearward-vergent thrusts were more developed, especially on the side with higher compression speed. In the models compressed only from one direction, rearward-vergent thrusts were well developed, while forward-vergent thrusts were rarely seen. These facts show that substrate contraction and asymmetric compression can facilitate the development of rearward-ver-gent thrusts. A comparison of the experimental results with actual sections in northern Qaidam Basin suggests that substrate contraction and asymmetric compression are probably responsible for the distinctive structures in this region, and the Cenozoic deformational structures must have resulted from the asymmetric lateral compression, mainly from Qilian Mountain, with the participation of substrate contraction.