西安北郊草店村河漫滩沉积与洪水变化

发布时间：2018-04-30 21:28

本文选题：河漫滩沉积 + 洪水事件　；参考：《地质论评》2017年02期

【摘要】：根据野外考察、粒度分析及历史文献资料,研究了西安北郊草店村剖面在距今900~660 a形成的渭河漫滩沉积和洪水变化。结果表明,在距今900~660 a形成的草店村剖面洪水沉积分层明显,能够指示洪水事件和洪水深度。草店村剖面洪水沉积厚度为5.25 m,可划分为26个沉积层,指示了26次规模不同的洪水事件。洪水沉积厚度和粒度成分显示,草店村剖面的26个洪水事件发生时河漫滩上的洪水深度均大于2.2m;剖面下部第17~第26层沉积时漫滩上的洪水深度为4.0~7.0 m,河床水深为6.2~8.5 m;中部第8~第16层沉积时漫滩上的洪水深度为3.0~5.0 m,河床水深为6.6~9.0 m左右;上部第1~第7层沉积时漫滩上的洪水深度为2.2~3.0 m,河床水深为7.2~8.6 m。草店村剖面中部和下部的洪水沉积以中砂和细砂为主,剖面上部以粉砂和极细砂为主,指示的洪水规模比距今120 a来西安渭河洪水显著大。草店村剖面中的第12、16~26层代表的是特大洪水事件。西安北郊渭河在距今900~660 a发生的大洪水主要是由当年降水量的明显增加引起的。
[Abstract]:Based on field investigation, grain size analysis and historical literature data, the sediment and flood changes of Weihe River floodplain formed in Chaodian Village, North suburb of Xi'an, from 900 to 660 years ago were studied. The results show that the flood stratification of Caodian village profile formed at 900 ~ 660a is obvious and can indicate the flood event and flood depth. The flood deposit thickness of Caodiancun section is 5.25 m, which can be divided into 26 sediment layers, indicating 26 flood events of different scale. The thickness and particle size composition of the flood deposits show that, The flood depth on the floodplain was more than 2.2 m when the 26 flood events occurred in Chaodiancun section, the flood depth on the floodplain was 4.0 ~ 7.0 m when the lower layer 17 ~ 26 was deposited, the water depth of the river bed was 6.2 卤8.5 m, and the floodplain in the middle part of the section was deposited in the 8th ~ 16th layer. The depth of flood is 3.0 m and the depth of river bed is about 6.69.0 m. The flood depth on the floodplain and the water depth of the riverbed are 2.2mand 8.6mrespectively when the upper layer 1 ~ 7 is deposited. The flood deposits in the middle and lower part of the Chaodiancun section are mainly medium sand and fine sand, the upper part of the section is silt and very fine sand, indicating the flood scale is significantly larger than that in Xi'an Weihe River 120 years ago. Caodian village section of the 12s 16-26 is representative of the catastrophic flood event. The flood of Weihe River in the north suburb of Xi'an was mainly caused by the obvious increase of precipitation in the year 900 ~ 660a ago.
【作者单位】：陕西师范大学旅游与环境学院;中国科学院地球环境研究所黄土与第四纪地质国家重点实验室;
【基金】：中国地质调查局西安地质调查中心“关中盆地第四系形成与演化”地质调查项目(编号:水[2016](4)) 国家自然科学基金国际合作项目(编号:41210002) 中国科学院黄土与第四纪地质国家重点实验室项目(编号:SKLLQG1626)的研究成果~~
【分类号】：P512.2;P333.2

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