湖北弥陀寺汉江段北宋时期古洪水研究

Study on palaeoflood in Northern Song period at Mituosi segment of Hanjiang River,Hubei Province

对湖北汉江郧县弥陀寺河段的地貌进行了考察,在该河段一级阶地上发现了黄土-古土壤剖面。对剖面进行了样品采集和详细的分析。结果表明,剖面中记录了一期古洪水事件。通过OSL断代及地层对比,确定此期古洪水事件发生于北宋时期(公元900-1000年)。用两种方法确定了古洪水的水位高程,并对两种方法所得的结果进行了对比。这次古洪水事件的洪峰流量在58620~64270 m3/s之间。研究结果可供汉江上游的防洪工程建设参考。

The geomorphological investigation was carried out in Mituosi segment of Hanjiang River,Yunxian County,Hubei Province. Holocene loess-paleosol profile was found at the Mituosi site on the first level terraces of the river. Samples were collected from the site and analyzed in laboratory in detail. Results show that the profile recorded a stage of palaeoflood event. By OSL dating and stratum contrast,it is found that this stage of palaeoflood occurrod in Northern Song period(900- 1 000 B C). The water level elevation of the palaeoflood was determined by two methods and their results were compared each other. The peak discharge of the palaeoflood ranges from 58 620 m3/ s to64270 m3/ s. The results may give a reference to the flood control projects in the upper reaches of Hanjiang River.