基于Sentinel-2B数据的阿尔金断裂带中东段多级别位移及第四纪滑动速率限定

    Multi-level displacements and Quaternary slip rate limit in the middle and eastern section of Altyn Tagh fault zone based on Sentinel-2B satelite data

    • 摘要:
      研究目的 定量获得走滑断裂在地质历史时期的活动速率是大陆动力学研究的基础,也是了解岩石圈变形机制,以及其随时间动态演化的重要支撑。获得精确的定量结果主要取决于对现有及残存断错地貌标志的研究,目前大多数研究主要利用沿走滑断裂两盘被位错的特征地质体限制十千米级—百千米级的水平位移,较年轻的地貌单元则用来限定晚第四纪以来的米级—百米级小幅度位移,而介于两者之间的千米级断裂位移量研究较缺乏。
      研究方法 在阿尔金断裂带中东段利用Sentinel-2B多光谱影像数据,融合特定波段数据的图像增强处理技术,结合地质填图结果开展研究。
      研究结果 准确限定2处测区和平乡西和石包城东十米级—千米级水平位移,分别为50~130 m和3~5 km,根据已有地层年代,估算断裂滑动速率分别为11.8 mm/a和1.2~5.7 mm/a。
      结论 本次结果研究与前人获得的万年尺度的活动构造速率和10 a尺度的现今变形速率基本一致,为下一步结合沉积物源和适当的年代学测试方法,厘定精确的更长时间尺度的断裂滑动速率,以及完善走滑断裂在第四纪以来的活动历史提供了新的解决途径。

       

      Abstract:
      Objective Quantitative acquisition of the activity rate of strike slip faults in geological history is the basis of continental dynamics research, and also an important support for understanding the deformation mechanism of lithosphere and its dynamic evolution process over time. Obtaining accurate quantitative results mainly depends on the study of the existing and residual dislocation geomorphic indicators. At present, most studies mainly use the characteristic geological bodies that are dislocated along the two sides of the strike slip fault to limit the horizontal displacement of ten kilometers to one hundred kilometers, while the younger geomorphic units are used to limit the small displacement of meters to one hundred meters since the late Quaternary. However, studies on kilometer−scale fault displacements, which lie between these two extremes, are relatively scarce.
      Methods This paper attempts to use Sentinel−2B multispectral image data, adopting an image enhancement processing technique fusing specific band data, and geological mapping results in the middle east section of the Altyn Tagh fault zone to accurately limit the horizontal displacement of ten meters to kilometers in the west of Heping town and the east of Shibaocheng town in two survey areas, which are about 50~130 m and 3~5 km, respectively.
      Results According to the existing stratigraphic age, the estimated fault slip rate is 11.8 mm/a and 1.2~5.7 mm/a, respectively.
      Conclusions It is basically consistent with the ten thousand years scale active tectonic rate and the ten−year scale current deformation rate obtained by predecessors, which provides a new solution for the next step to determine the accurate long−term scale fault slip rate in combination with sediment source analysis and appropriate Chronology testing methods, and improve the activity history of strike slip faults since Quaternary.

       

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