西秦岭泥盆纪西汉水群、三叠纪隆务河群叠加褶皱的存在证据及地质意义  

EVIDENCE OF SUPERPOSED FOLDS AMONG DEVONIAN XIHANSHUI GROUP AND TRIASSIC LONGWUHE GROUP IN WEST QINLING AND ITS GEOLOGICAL SIGNIFICANCE

作　　者：张伯祥[1] 梁国冰 

机构地区：[1]甘肃省地质调查院,甘肃兰州730000 [2]长安大学地球科学与资源学院,陕西西安710054

出　　处：《甘肃地质》2017年第2期38-43,共6页Gansu Geology

基　　金：官亭幅等3幅区调;卢家庄等6幅区调;甘肃省区域地质志新编(项目编码:12120113047500;121201130474002;12120113013500)

摘　　要：在西秦岭泥盆纪、三叠纪地层中普遍存在着叠加褶皱,由于覆盖和两期褶皱的近共轴特征,使得这种叠加褶皱的识别和填绘长期未能得到合理解决。多期面理的识别和空间关系、小褶皱枢纽和轴面产状统计,为叠加褶皱的存在提供了依据。地质体平面形态的透镜化和走向弯曲,是两期叠加褶皱干涉图象的平面特征。有效解析叠加褶皱,合理建立构造模型,不仅对区域构造发展的历史具有重大意义,在指导地质填图工作的进行方面也具有不可替代的作用。甘肃西秦岭地区大面积分布的泥盆纪西汉水群和三叠纪隆务河群,以浅变质和砂板岩夹灰岩的沉积建造为特点,地质填图中厚度巨大的假象是叠加褶皱构造叠置所成,是构造复合的结果。多期面理关系的研究和小褶皱枢纽产状的统计分析,认为有两期近共轴、小角度的褶皱叠加。There are lots of superposed folds among Devonian Xihanshui Group and Triassic Lo e Group expansively outcropped in west Qinling region of Gansu Province. The stratigraphy are sedimentary forma- tion of light metamorphic sand slate with limestone. Due to covering and near coaxial features of two periods folds, the issue of recognition and mapping these superposed folds are not resolved. By recognizing, collecting and analyzing special relation of multi-period foliation, the occurrence of hinge and axial surface of wrinkling will provide existence evidence of superposed folds. The plan modahty of geological body has the appearance of lens and curved strike which are the feature of interference pattern of superposed folds caused by two stage movement. It will be significance for interpreting the regional tectonic evolution by analyzing superposed folds and establish- ing geological structural model. The large and thick false geological body on geological map is due to superposi- tion of folds, it is the product of re recombined structures.

关 键 词：叠加褶皱 西汉水群 隆务河群 西秦岭 

分 类 号：P542[天文地球—构造地质学]