论文部分内容阅读
重力滑脱构造在盆地演化中较为常见,地层或岩体在重力作用下向下方滑动所产生的构造变动存在广泛。歧口凹陷为渤海湾新生代盆地内一个次级构造单元凹陷,其特点是新生代沉积巨厚且构造活动强烈,为重力滑脱和相关构造形成提供了发育条件。按照滑脱面性质的不同,将歧口凹陷的滑脱构造分为3类:地层—断裂复合滑脱、顺层滑脱和断裂滑脱。在该凹陷中选其各自具代表性的构造,如埕北滑脱构造、塘沽新港滑脱构造和大张坨滑脱构造进行结构特征和演化等方面剖析。研究认为,歧口凹陷滑脱构造形成的主控因素为新生代凹陷区快速沉积、凸起带强烈隆升、前第三纪地层的滑移层和热力作用。滑脱构造大多有褶皱和断裂相伴生,其组合方式不同可为油气成藏提供有利条件。
Gravity slip structures are more common in the basin evolution, and there are many structural changes caused by the downward sliding of the strata or rock mass under gravity. The Qikou Sag is a secondary tectonic unit depression in the Bohai Bay Cenozoic basin characterized by thick sediments and intense tectonic activity in the Cenozoic. It provides the conditions for the development of gravitational slip and related tectonics. According to the different nature of slip surface, the slip structures of Qikou sag are divided into three types: strata-fault slip, slip seam and fault slip. In the sag, we choose their respective representative structures, such as the Northern Peiping Uplift Structure, the New Tangkou Slough Structure of Tanggu and the Dachang Tuo Sliding Structure to analyze the structural characteristics and evolution. The study suggests that the main controlling factors for the formation of the slip-formation in the Qikou sag are the rapid deposition of Cenozoic depressions, the strong uplift of the uplift belt, the slip layer and the thermal effect of the Pre-Tertiary strata. Most of the slippage structures are accompanied by folds and faults, and the different combination methods can provide favorable conditions for hydrocarbon accumulation.