中文摘要：

目的系统研究韧性基底层黏度对褶皱-冲断带变形特征的影响。方法采用不同韧性基底层黏度砂箱模型进行系列实验。结果韧性基底层在黏度较高的情况下，褶皱．冲断带以前冲断层为主导，并以前展方式扩展。随着韧性基底层黏度的降低，后冲断层逐渐占主导，形成双冲向、且比较典型的隔槽式褶皱．冲断带。结论韧性基底层黏度对褶皱．冲断带变形演化具有十分显著的影响，宽阔低锥度的双冲向褶皱-冲断带的形成可能与其下伏存在的软弱基底层有关。韧性基底层的存在是形成隔槽式褶皱．冲断构造样式的重要因素。

英文摘要：

Aim To systematically investigate the influence of viscosity of ductile substrate on deformational features of fold-and-thrust belts. Methods Experiments of a series of sandbox models with a ductile substrate of different viscosities were conducted. Results The experimental results show that fold-and-thrust belts formed in the models with substrata of high viscosity are predominated by forward-vergent thrusts and develop in a frontward sequence. As the viscosity of substrata deereases, rearward-vergent thrusts gradually increase and fold-and-thrust belts are often predominated by dual vergent thrusts and consist of typical trough-like folds. Conclusion It is indicated that viscosity of substrata has played an important role in deforation evolution of fold-and-thrust belts. Wider fold-and-thrust belts of lower taper and dual vergenee are probably related to their weak substrata. Existence of ductile substrate is an important factor in the formation of trough-like folds in a fold-and-thrust belt.