生长指数与断层落差的对比研究

A COMPARISON OF THE FAULT GROWTH INDEX WITH FAULT THROW

通过对断层落差与生长指数法对比研究,分析了二者应用的假设条件、应用范围及研究断层活动特征时的优缺点,认为在准确地层对比的基础之上,断层生长指数法要求凹陷内不同部位、各时代的沉积速率一致,断层上下盘没有大的沉积间断,而断层落差法则假设剥蚀区内断层上下盘的被剥蚀厚度保持一致,不必考虑沉积间断。生长指数法、断层落差法可以在一定程度上用于挤压和断陷盆地中研究反转断层和生长断层的活动强度和活动历史;而断层落差法在分析断陷盆地中的生长断层时更为直观、可靠,尤其是上升盘地层缺失及具有相对升降幅度差的生长断层的活动强度。开展了不同方法对比研究,可以得到更多的信息,以期更好地探讨研究区的断层演化或活动历史。

By comparing fault growth index with fault throw analysis, their hypothesis conditions of application, application range, as well as virtue and defect of fault activity intensity research are analyzed, it is recognized, on the basis of accurate stratigraphic correlation, the fault growth index demands that there is consistent depositional velocity on different part in a depression and no depositional break on the both sides of a fault, fault throw analysis is based on the hypothesis that there is, on the both sides, consistent erosion sediment thickness at eroded area, and that it is not necessary to consider depositional break. it is proved that growth index and fault throw can be used to research the active intensity and active history of inversion faults and growth faults in compressional basins and fault basins in some extent. But the fault throw is more intuitionistic and reliable when it is used to analyze the active intensity of growth faults especially those growth faults which are absence of the upthrow sides stratum and have relative evolution differential. Comparative study of different geochronological methods can give more valuable information of evolution and activity of the faults of the same area.