【摘要】 江南古陆东北缘古生代—早中生代盖层中发育的褶皱构造属性逐渐被认识,但该区是否存在叠加褶皱及其叠加样式如何则未见报道。通过野外调查,发现江南古陆东北缘发育加里东期、印支期褶皱构造。通过对区内叠加褶皱特征和应力场恢复研究,并应用构造解析和赤平投影法研究叠加褶皱的几何学和运动学特征,显示盖层发育3期区域性叠加褶皱变形:区内早期遭受SN向挤压,形成加里东晚期近EW向褶皱(第一期褶皱);其后遭受SE—NW向挤压,形成印支早期NE向或NNE向褶皱(第二期褶皱);晚期遭受NE—SW向挤压,形成印支晚期—燕山早期近SN向或NNW向褶皱(第三期褶皱)。区域叠加褶皱主要有横跨和斜跨叠加褶皱,发育多样干涉样式。结果表明:第二期褶皱斜跨第一期褶皱,形成了区内基本构造格局。深入研究叠加褶皱构造特征和变形演化史,对区内构造格架重建和地质找矿均具有重要意义。更多还原

【Abstract】 The tectonic attribute of the capping fold developed in Paleozoic-Early Mesozoic in the northeastern margin of Jiangnan orogen is gradually recognized,but there is not research report about the superposed folds and their superposed patterns in the study area at present.Based on the field investigates,Caledonian and Indosinian fold structures develop in the northeastern margin of Jiangnan orogen.Based on the characteristics of the superposed folds and the restoration of stress field,the geometry and kinematics characteristics of superposed folds are discussed by structure analysis and stereographic projection method,and there are three stages of the capping superposed fold deformation,including the first fold(F1),the second fold(F2)and the third fold(F3).In the early stage,the cap suffers SN compression,and forms Late Caledonian EW-nearly fold(F1);then,the first fold suffers SE-NW compression,and forms Early Indosinian NE or NNE fold(F2);in the later stage,the second fold suffers NE-SW compression,and forms Late Indosinian-Early Yanshanian SN-nearly or NNW fold(F3).Theregional superposed folds mainly have vertical span and slant span styles,and develop various Interference patterns.The results show that the second fold diagonally overprints the first fold,and forms the basic structural pattern in the area.The study on the structural characteristics and deformation evolution of superposed folds has great significance on the reconstruction of tectonic framework and geological prospecting.更多还原