中文摘要：

位于湖北省东部黄石地区制图尺度的近东西向黄荆山向斜和桐梓堡背斜是在印支期造山作用时形成的,主要由古生代及三叠纪沉积岩层序列组成。其中的下、中三叠统包括页岩、泥灰岩、石灰岩、白云质灰岩和白云岩等层状岩系。从构造地质学的观点出发,由下而上可划分为3个力学分层单位或组合,相互间存在有不同的黏度比或相对强度。在大型褶皱翼部,发育一系列中小型褶皱（其振幅从几米至上百米）,如屋顶和墙壁状构造、膝状褶皱、平卧褶皱、翻转及叠褶构造等,覆于层理面及低缓角度正断层面之上。详细的三维空间构造解析指出,这些复杂的中小型构造产状和组合样式,与通常的寄生牵引褶皱和大的褶皱关系是相反的,即上层的相对运动或流动指向向斜的槽部,显示重力导致的滑动构造特征。这种滑动构造只是一类继发性的独立构造现象,可以解释为是在重力不稳定性影响下,部分沉积岩层沿着先存的倾斜层理面或拆离剪切带向下坡有限滑动的结果。所发育的特征性构造取决于涉及的岩层及力学分层单位的能干性或相对强度。在大型褶皱翼部岩层向下滑动的尺度、速度及可行性,与层理面的倾斜度及拆离带的厚度、黏度等因素相关。类似的重力滑动构造在中上扬子地区的沉积岩层中常可观察到,同时,地表的滑坡、岩崩及山体垮塌等地质灾害过程与有限的重力滑动构造的发育,其基本原理和许多特征都是相似的。强调指出,重力不稳定性作为地质过程、构造变形及许多地质灾害的起因,在地壳的不同层次和地表都有显示。

英文摘要：

The major map-scale Huangjingshan syncline and Tongzibao anticline with a predominant E-W trend, formed during the Triassic Indo-China orogeny, are exposed in H uangshi area, eastern Hubei Province. The folds are mainly composed of Paleozoic and Triassic sedimentary strata in which the Triassic sedimentrary sequence consists of a series of interhedded shales, marls, limestones, dolomitic limestones and dolomites with different values of viscosity contrast. A variety of meso-scale folds, from a few metes to over hundred metres in amplitude, such as roof and wall structure, knee fold, recumbent fold, flap and cascade etc. with flat-lying axial surfaces, resting on bedding planes and low-angle normal faults, occurr on the limbs of the major map-scale folds. Detailed three-dimensional structural observations and analyses have revealed that the intricate structures have an attitude or aggregate that is the reverse of the normal parasitic drag-fold relationship to the major folds. They clearly point to the movement or flow of the upper beds towards the synclinal troughs, and display features of gravity-induced sliding structures. The sliding structures are only secondary, independent phenomena, and hence can be best interpreted as products of the gravitational instability, leading to a limited sliding along the pre-existing dipping bedding planes or detachment shear zones. The particular structures developed depend on the competency or relative strength of the mechanical stratigraphic units and the sedimentary strata involved. The extent of the limited sliding structures and the ease or speed of sliding of bedded rocks down the flanks of the major anticline increase with in creasing bedding plane dip and detachment zone thickness. Similar structures are often seen within sedimentary strata in the upper-middle Yangtze River regions. At the same time, there is a similarity of principle in rockslide or avalanche movements and those of the limited sliding structures. It is emphasized that the gravitational instability appe