应用古文化层埋深确定汾渭盆地沉积速率的研究

DETERMINATION OF SEDIMENTATION RATE OF FEN WEI BASIN FROM THE BURIED DEPTH OF OLD CULTURAL LAYER

摘要:

根据49处仰绍至东周古文化遗址埋深数据研究了距今7000～2500年汾渭盆地内部的沉积速率.结果表明,盆地内部的凸起地区沉积速率一般小于凹陷地区,如渭河凹陷的平均沉积速率为0.46mm/a,临汾凹陷的平均沉积速率为0.36mm/a,而临潼凸起和襄汾凸起的沉积速率为0.20mm/a左右.分析各时代的沉积速率还发现,在仰绍(距今5000年)之前渭河盆地内凹陷的沉积速率明显小于仰绍之后,宝鸡凸起还由东周之前的相对下降变为相对上升.沉积速率相对较大的地质单元往往是地震活跃的地区.

Abstract:

The sedimentation rate of Fen wei basin in recent 7 000～2 500 years has been studied from the buried depth data of 49 old cultural relics from the Yangshao to East Zhou dynasties.The results show that the average sedimentation rates in Weihe depression and Linfen depression are 0.46 mm/a and 0.36 mm/a respectively.In general,the sedimentation rate in upheavals is smaller than that in depression in the basin.Both the rate in Lintong upheavals and Xiangfen upheavals are 0.20 mm/a. The relative differences of sedimentation rate between every geological element are identical with distribution and movement characteristics of geological structures.It can also be discovered by analysis of sedimentation rate in various times that sedimentation rate in Weihe depression before the Yangshao (about 5 000 years ago) is smaller than after that. The sedimentation rate increased in depression and decreased in upheaval with time. Strong earthquakes in the Fen wei basin are mainly located in the geological units with relatively large sedimentation rate.