中文摘要：

对川东—湘鄂西断褶带内鄂西地区的弧形构造,从构造剖面特征、叠加褶皱样式和断裂性质入手进行几何学和运动学分析。结果发现鄂西弧形构造具有多期变形特征：早期普遍为北东东向的直线型褶皱,随着弧形带扩展,在东、西两翼分别发育右行和左行的逆冲—走滑断裂,同时分别形成北北东向和北西西向的弧形褶皱。晚期弧形带中部发育北北东向构造并叠加改造了早期北东东和北西西向褶皱,同时在黄陵背斜以西还发育交切早期构造的北北西向仙女山右行走滑断裂。根据弧形带扩展的几何学—运动学分类原则,并结合前人的古地磁研究结果,推测鄂西弧形构造应属于构造弯曲形成的弯曲弧。区域滑脱层和黄陵隆起阻挡可能是控制弧形样式的主要原因。区域滑脱层控制了拆离滑脱褶皱的构造样式; 黄陵基底隆起的阻挡作用使弧形带东翼进一步弯曲变形,并导致了构造应力场方向发生改变,造成了晚期北北东向与早期北东东向构造的叠加。由此恢复的鄂西弧形构造变形过程对于揭示川东—湘鄂西断褶带构造演化具有重要的指示意义。

英文摘要：

In northern Yangtze area,there are two Mesozoic arcuate fold-thrust belts,the southern Daba fold-thrust belt and the eastern Sichuan-Western Hubei fold-thrust belt.The origin of the southern Daba was due to the large arc-shape indentor（northern Daba divided by Chengkou-Fangxian thrust fault）and two basement uplift（Micangshan and Shennongjia）,but the origin of the eastern Sichuan-Western Hubei fold-thrust belt was not well understood.Based on the cross sections and field mapping,this paper analyzed the geometry and kinematics of the folds and faults in western Hubei province.We found that the fold-thrust belt was characterized by multi-phase deformation.The early phase deformation was dominant by straight fold trending NEE.During the propagation of fold-thrust belt,the eastern and western limbs were developed with curved folds trending NNE and NWW,respectively.The strike-slip faults with opposite slip direction were also formed in the two limbs.The late phase deformation was concentrated in the central fold-thrust belt,characterized by NNE-trending fold and NNW-trending strike-slip fault.The NNE-trending folds superposed on the NEE-trending folds,while the NNW-trending fault cut across the NWW curved in the eastern limb.The two-phase deformation suggested the varied structural stress field controlled by different factors.We conclude that the arcuate fold-thrust belt is orocline with vertical-axis rotation in western Hubei Province.The early phase deformation was controlled by detachment horizons.The late phase deformation was controlled by Huangling basement uplift,which held the propagation of eastern limb of the fold-thrust belt and intensified the curved deformation.