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准噶尔盆地南缘西部山前褶皱—冲断带构造分带特征及形成演化
Characteristics of tectonic zoning and formation and evolution of the pre-mountain folded-alluvial belt in the western part of the southern margin of the Junggar Basin
【摘要】 准噶尔盆地南缘西部构造呈新的构造叠置特征和复杂的复合叠加构造样式,叠加构造在空间分布上具有明显的分带特征。根据野外地质调查和地震解释资料,采用平衡剖面恢复、楔型构造理论和构造地质学分析方法,研究复杂叠加构造变形差异及分带特征。结果表明:准噶尔盆地南缘西部发育受基底卷入与顺层滑脱联合与差异控制下的空间断褶体系,褶皱发育受断层控制,褶皱与断层相互叠加形成构造楔、双重构造、突发构造等复合构造样式,表现为多期活动特征。研究区按构造变形性质及变形差异可划分为山前逆冲推覆构造带、基底卷入型褶皱—冲断带、盖层滑脱型褶皱—冲断带3个构造带;其中,基底卷入型褶皱—冲断带与第一排断褶带重合,受控于基底卷入型断裂体系,发育基底卷入式大型构造楔、背形堆垛式双重构造与前倾双重构造,背斜轴线与断层线平面重合度高;盖层滑脱型褶皱—冲断带包括第二和第三排断褶带,受控于顺层滑脱型断裂体系,发育断展褶皱,背斜轴线与断层线平面重合度低,构造垂向上具有分层差异,构造变形程度自南向北表现为由强至弱。挤压应力作用的时期和强度、滑脱断层的向北滑脱、构造楔的楔入长度及推挤距离、滑脱层的厚度和上覆地层厚度,以及沉积时代、沉积速率和岩性差异等因素是引起研究区构造垂向分层、南北分带的原因。该结果对明确研究区构造发育及下一步油气地质勘探具有指导意义。
【Abstract】 The interpretation of high-precision seismic data reveals that the tectonics of the western part of the southern margin shows new tectonic superposition characteristics and more complex superposition composite tectonic style,and the superposition tectonics has obvious zoning characteristics in spatial distribution.Combined with the field geological investigation,seismic interpretation,equilibrium section restoration,and the use of wedge tectonic theory and tectonic geology analysis methods,the complex superposition tectonic deformation differences and zoning characteristics were investigated.The study shows that:the western part of the southern margin develops a spatial folding system under the joint and differential control of basement involvement and downstream sliding,and the development of folds is controlled by faults,which are superimposed on each other to form a tectonic wedge,double tectonics,sudden tectonics and other composite tectonic styles.The western part of the southern margin is divided into three tectonic belts,namely,the pre-mountain retrograde thrust-overthrust tectonic belt,the basement-involved fold-rupture belt,and the cover-slip fold-rupture belt,according to the nature of the tectonic deformation and the difference of the deformation,among which the basement-involved foldrupture belt is overlapped with the first row of the fault belt and controlled by the basement-involved rupture system,and the large-scale tectonic wedge of basement-involved,the dual structure of the dorsal stacking and double-tectonics,and the double-tectonics of the forward-dipping tectonics are developed,and the dorsal axes overlap the planes of faults with high coincidence degree.The slip-type foldrupture zone includes the second and third rows of fold zones,which are controlled by the downstream slip-type rupture system,with the development of break-spreading folds,low overlap between the dorsal axes and the fault line planes,and layered differences in the vertical direction of the tectonics;the overall degree of tectonic deformation from the south to the north shows that it is decreasing from strong to weak.The period and intensity of extrusion stress,the northward slip of the slip fault,the wedge length of the tectonic wedge and the pushing distance,the thickness of the slip layer and the thickness of the overlying strata,the depositional age,the depositional rate,and the difference in lithology are the causes of the vertical stratification of the tectonics of the western part of the southern margin and the north-south division of the zone.The explicit construction of deformation differences and the refined division of zoning have important implications for clarifying the development of geological structures in research areas and guiding oil and gas exploration activities.
【Key words】 western part of southern margin of Junggar Basin; pre-mountain belt; thrust and nappe tectonic belt; fold-thrust belt; construct style; structural deformation; zoning characteristics; tectonic evolution;
- 【文献出处】 东北石油大学学报 ,Journal of Northeast Petroleum University , 编辑部邮箱 ,2024年01期
- 【分类号】P618.13
- 【下载频次】102