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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。
Overlying Devonian and Triassic strata in West Qinling have superimposed folds generally. Due to the nearly coaxial features of the cover and the two folds, the identification and the filling of the superimposed folds have not been properly solved for a long time. Multi-faceted identification and spatial relationships, small fold hinge and axial shape statistics provide the basis for the existence of superimposed folds. The planarization of the plane body and the bending of the plane are the planar features of the superimposed fold-interference image of the two phases. The effective analysis of superimposed folds and the reasonable establishment of structural models are of great significance not only for the history of regional tectonics but also for guiding the work of geological mapping. The large-scale Devonian West Han flood and the Triassic Longwuhe Group in the western Qinling area of Gansu Province are characterized by the deposition of shallow metamorphism and sandstone-slate limestone. The huge thickness of the geological mapping is a superimposed fold structure Stacked into, is the result of structural compound. The study of multi-period relationship and the statistical analysis of the origin of small fold hinge, we consider that there are two fold superimposed near-axis and small-angle.