渤中凹陷石南陡坡带断层活动对古近系砂砾岩扇体规模的定量控制

The Quantitative Control of Fault Motion of Shinan Steep Slope Zone in Bozhong Depression on the Scale of Paleogene Glutenite Fan

位于渤中凹陷石臼坨凸起南部陡坡带的控盆断裂在古近纪活动频繁。为了定量研究断层活动对砂砾岩沉积的控制作用,选用断层活动速率法研究不同时期、不同位置的断层活动特点,同时结合地震属性、测井资料在空间上刻画不同层段的砂砾岩体,求取砂砾岩体面积、体积、延伸距离、尖灭角等定量参数,统计分析了断层活动速率与砂砾岩体参数间的量化关系。研究表明:石南控盆断裂在不同时期、不同位置的活动速率具有显著差异,断层活动速率在时间、空间上的变化导致了砂砾岩体参数的差异,定量研究发现断层活动速率较大时发育的砂砾岩体面积和体积一般较小、延伸距离较近、尖灭角较大,而当断层活动速率较小时砂砾岩体面积和体积一般较大、延伸距离较远、尖灭角较小。通过砂砾岩体参数和断层活动速率的统计,针对研究区提出了古近系近源砂砾岩扇体规模与断层活动速率之间的定量关系。

The basin-controlling faults in the southern steep slope zone of Shijiutuo uplift of Bozhong depression were very frequent in Paleogene.In order to conduct quantitative research on the controlling effect of fault motion on the deposition of glutenite, the area, volume, extended distance,thinning out angle and other quantitative parameters of glutenite were gained, and the quantitative relation between fault motion rate and the parameters of glutenite mass was statistically analyzed, by studying the features of fault motion in different times and positions by means of fault motion rate method, and depicting the glutenite mass in different layers in spatial level after considering the seismic attributes and logging data.The results showed that:the basin-controlling faults in the southern steep slope zone of Shijiutuo uplift have different motion rate in different times and positions, and the changes of fault motion rate in time and space result in the difference of parameters of glutenite mass.In the quantitative research, we find out that when the fault motion is very frequent, the area and volume of glutenite mass are generally small, the extended distance is close, and the thinning out angle is large, while the fault motion is less frequent, the area and volume of glutenite mass are generally large, the extended distance is far, and the thinning out angle is small.Through the statistics of parameters of glutenite mass and the rate of fault motion, the quantitative relation between the scale of Paleogene proximal glutenite fan and the rate of fault motion is proposed for the study area.