摘要
河流河漫滩相物质粒度的变化是指示洪水强弱的重要标志。在L9时期,渭河共发育了5.3 m的河漫滩,其主要由粘土和沙层组成。选用粒径>63μm作为指示大型洪水的指标,年代的确定通过黄土的中值粒径进行黄土古土壤的对比。研究表明在这个时期,至少发生了四次较大的洪水,尤以最后一次洪水规模和强度最大,与陇西盆地记录的L9时期气候变化一致。
The grain size variation of flood plain can indicate palaeoflood events. On basis of correlation of loesspaleosol and other classic section, the paper indicates that the loess have formed since S8 and the flood plain have formed during L9 （0.87 -0.94 Ma）. During L9, flood plain deposit of Weihe River, Shaanxi Province, China, is 5.3 m in thickness and consists of silt layers and sand layers. Coarse sand （ 〉 63 l.zm） is chosen as the indicator to the big palaeoflood, and during L9, there are four big palaeofloods in Weihe River, especially the fourth has the greatest flood scale and strength, which is in accord with climate change records of Longxi Basin of Gansu Province and Ningxia Hui Autonomous Region during L9 Period.
出处
《干旱区地理》
CSCD
北大核心
2007年第2期247-250,共4页
Arid Land Geography
基金
国家自然科学基金(40471016
40401007)
教育部重点项目(20030730017)
关键词
古洪水
粒度
河漫滩
黄土
paleoflood
grain size
flood plain loess
Layers
