【摘要】 河池-宜州断裂带是一条东西向构造带,位于扬子地块东南缘雪峰山构造带南部,与扬子地块主体NE向的构造格局明显不同,其成因始终不明确。本文通过遥感构造解译、野外地质观察、构造剖面绘制、地震和MT剖面解释等手段,对河池-宜州断裂带东段进行了空间上由浅入深的系统研究,研究表明断裂带总体表现为向北逆冲的叠瓦构造分割了雪峰山南段构造体系和桂中坳陷构造体系;河池-宜州断裂带经历了多期次活动历史,其中现今构造格局主体由印支期和燕山期复合动力学机制下形成的,西段主要由印支期向南的弧形逆冲推覆阶段形成,东段主要由燕山期向西的弧形叠瓦式逆冲推覆奠定,它们的弧顶正好在宜州附近交接。更多还原

【Abstract】 The Hechi-Yizhou fault zone is an east-west structural belt in the southern Xuefeng Mountains of the Yangtze block. It is significantly different from the NE-trending tectonic framework in the Yangtze block. But the cause is not clear. Based on remote sensing image,abundant field data,geological structural sections,MT and seismic interpretation,this paper systematically analyzed the Hechi-Yizhou fault zone from the surface to the depth. This research shows that the structural pattern of the Hechi-Yizhou fault zone is a north-trending imbricate structure,which separates the southern Xuefeng structural system from the Guizhong depression. This fault zone has experienced polyphase activities. The E-W-trending structures shaped its initial geometry in the Caledonian. During the Hercynian,it began to rift,controlling the deposition of the Guizhong depression. During the Indosinian,the fault zone intensively reversed and thrusted towards southeast at the Hechi-Yizhou segment as a result of the collisions between the Indochina and Yangtze blocks. This structure was propagated to the east,and formed a southward arc-convex belt finally. Then,the east-west compressional stress field in the Yanshanian generated the arc-like west-trending imbricate structure. The Liucheng-Zhongdu segment of the fault zone is its northward-imbricated ramp. Due to the superimposition of two-stage arc-like structures,a triangle zone occurred near the Hechi-Yizhou segment. Meanwhile,the main faults were linked together and strongly activated. The current tectonic framework is mainly a result of the complex geodynamic evolution during the Indosinian orogeny and Yanshanian orogeny: The west segment is the south-trending arc-like imbricate structures in the Indosinian orogeny,and the east segment is the west-trending arc-like imbricate structures in the Yanshanian orogeny. The two arcs just linked at the vicinity of Yizhou City.更多还原