黄河口凹陷新生代断裂体系与构造演化

Cenozoic faulting system and tectonic evolution of the Huanghekou Sag

针对黄河口凹陷新生代断裂体系与构造演化尚不明确的问题,运用三维地震资料、剖面特征分析和水平相干切片分析相结合的手段,研究了黄河口凹陷新生代断裂体系与构造演化发育规律。结果表明:新生代以来,受多期构造运动的影响,研究区断裂体系具有多方向、多性质、多期次叠加复合特征——"三三特征",即3组优势方向断裂、3种断裂性质、3期构造演化;凹陷发育近EW向(NWW向)、NNE向(近SN向)、NE向3组优势方向断裂,近EW向和NE向断裂为拉张或走滑-拉张性质断裂,NNE向断裂为走滑性质断裂;盆地具有典型的断陷与坳陷叠置结构;可划分为3个构造演化期次,即E_2k—E_(2s_4)早期裂陷阶段、E_(2s_3)—E_3d裂陷伸展阶段和N_1g—Qp裂后拗陷阶段。该研究对黄河口凹陷后续油气勘探具有重要的指导意义。

With regard to uneerlainties in Cenozoic fauting system and tectonic evolution in the Huanghekou sag, 3D seismic data, profile feature analyses and horizontal cohesion slice analyses have been performed to highlight Cenozoic faulling system and patterns of tectonic evolution in the Huanghekou sag. Research results show ： since Ce- nozoic, due to impacts of tectonic movements in multiple stages, faulting systems within the study area have composite features involving multiple direction, multiple properties and stacking of multiple stages. In other words, the faulting systems have ＂Triple-three features＂ ： 3 groups of faults in preferred directions, 3 kinds of faults, 3 stages of tectonic evolution; The Sage contains faults in three favorable directions： approximately EW （NWW） , N NE （SN） and NE. Faults in approximately EW and NE directions are tension or strike-slip-tension in nature, whereas faults in NNE are strike-slip in nature; The Basin has typical structure with stacking of fault and depressions; The System can be divided into 3 teetonie evolution stages： E2k--E2s4 early faulting stage, E2s3--F, sd fault extension stage and N Ig--Qp post-faulting depression stage. Relevant researehes may provide faluable guidanee for future oil -gas exploration in the Huanghekou Sag.