在查明歧口凹陷构造空间分布特征基础上，运用现代区域构造演化思想、分析方法将歧口凹陷构造演化划分为６个主要阶段：（１）左行平移剪切阶段；（２）北西向拉张阶段；（３）北西向挤压阶段；（４）近南北向快速拉张阶段；（５）近南北向拉张和热沉降过渡阶段；（６）热沉降阶段。 On the basis of ascertaining the tectonic distribution of Qikou sag, the tectonic evolution of Qikou sag is divided into six main stages by the modern regional tectonic evolution thought: (1) left-lateral translation and shear stage; (2) northwestward Stretching stage; (3) northwest extrusion stage; (4) near the north-south rapid pull stage; (5) near the north-south stretch and thermal settlement transition stage;