沙湾断裂带探测及其活动性研究

发布时间：2018-04-29 01:29

本文选题：活动断裂 + 活动断裂探测　；参考：《江西理工大学》2015年硕士论文

【摘要】：沙湾断裂带是珠江三角洲内重要的断裂构造,其延伸长、影响区域大,成为了广州、佛山等周边城市发展的内部隐患。因此,针对沙湾断裂带开展研究,掌握其时空发展规律,判断其当前的活动情况,对当地开展防震减灾工作具有十分重要的意义。在搜集区域地质资料后,本研究有序开展了地表调查、槽探、地球物理勘探、土壤测氡、联合钻孔、年代测试等工作,主要从断裂地貌、近现代地震、断裂切割最新地层、断层气异常、年代测试结果等方面进行了断层活动性分析。基于分析结果,本文初步讨论了沙湾断裂带的形成演化过程。全文研究成果如下:(1)沙湾断裂带对珠江三角洲的现代地形地貌控制较弱,所诱发的地震震级也未超过6级,显示其活动性不强。(2)地表露头处普遍可见压扭、张剪性相互叠加,表明沙湾断裂带在多起重大构造事件作用下发生了多期活动。根据活动断裂探测结果反映,仅发现分支断裂紫泥-灵山断裂(F013)在大岗十八罗汉山处第四纪活动迹象明显,测年结果为晚更新世早期-中期,证明了F013在该处表现为活动断裂。但断裂带的其余分支均未发现断层错动第四系的现象,测年资料上也缺乏晚更新世活动的证据,因此现阶段无法将断裂带的其余分支评价为活动断裂。(3)根据断层气探测分析的结果,沙湾断裂带主断裂面F007的活动性较东侧的F008、F010更强,结合当前F007西侧的F013在断裂带内第四纪活动性最为显著的特点,此现象或许揭示了断裂带内部各分支断裂的活动规律,具体有待进一步验证。(4)沙湾断裂带在白垩纪燕山运动时期形成;古近纪时活动增强;在新近纪喜山运动第二幕时期活动显著,影响并控制着珠江三角洲基底地貌的形成;在第四纪期间活动性先减弱、后增强、再减弱,在近期总体表现弱活动断裂。
[Abstract]:The Shawan fault zone is an important fault structure in the Pearl River Delta. Its extension is long and the influence area is large. It has become the internal hidden danger of the development of the surrounding cities such as Guangzhou Foshan and so on. Therefore, it is of great significance for the work of earthquake prevention and disaster reduction to study the Shawan fault zone, master its space-time development law, and judge its current activities. After collecting regional geological data, this study carried out in an orderly manner the work of surface survey, trough exploration, geophysical exploration, soil radon measurement, combined drilling, age testing, etc., mainly from fault landforms, modern earthquakes, and fault cutting of the latest strata. Fault activity analysis was carried out on fault gas anomaly and age test results. Based on the analysis results, the formation and evolution of the Shawan fault zone are discussed in this paper. The results of this study are as follows: (1) the Shawan fault zone has weak control over the modern topography and geomorphology of the Pearl River Delta, and the magnitude of the induced earthquake does not exceed magnitude 6, indicating that its activity is not strong. 2) the pressure and torsion are generally visible at the outcrops on the surface, and the tension and shear superimpose on each other. It shows that the Shawan fault zone has been active for many periods under the action of many major tectonic events. According to the results of active fault detection, only the branch fault Zinie-Lingshan fault F013) is found to show obvious signs of Quaternary activity in the Lohan Mountains of Dagang 18, and the dating results are early to the middle of the late Pleistocene, which proves that F013 is an active fault there. However, the other branches of the fault zone have not found the fault dislocation of Quaternary, and the dating data are also lack of evidence of late Pleistocene activity. Therefore, it is not possible to evaluate the other branches of the fault zone as active fault. (3) according to the results of fault gas detection and analysis, the activity of F007 on the main fault surface of Shawan fault zone is stronger than that of F008 / F010 on the east side of the fault zone. Combined with the most prominent Quaternary activity of F013 on the west side of F007 fault zone, this phenomenon may reveal the activity law of each branch fault in the fault zone. It needs further verification that the Shawan fault zone formed during the Yanshanian movement in the Cretaceous, increased in the Paleogene period, and was significantly active in the second act of the Neogene Jixi Mountain Movement, which influenced and controlled the formation of the basement geomorphology in the Pearl River Delta. During the Quaternary period, the activity first weakened, then increased, and then weakened.
【学位授予单位】：江西理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P315;P542.3

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