地理科学 ›› 1982, Vol. 2 ›› Issue (3): 210-220.doi: 10.13249/j.cnki.sgs.1982.03.210

• 论文 • 上一篇    下一篇

滹沱河平原段现代沉积结构、构造特征

陈中原, 严钦尚   

  1. 华东师范大学地理系
  • 出版日期:1982-05-20 发布日期:1982-05-20

THE STRUCTURAL FEATURES OF RECENT ALLUVIAL SEDIMENTATION OF THE HUTUO RIVER ON PLAIN REACH,HEBEI PROVINCE

Chen Zhongyuan, Yan Qinshang   

  1. The Department of Geography, East China normal university
  • Online:1982-05-20 Published:1982-05-20

摘要: 本文研究的滹沱河平原段长180公里,它是洪、枯水期分明,季节性显著的河流。

Abstract: Hutuo River in Hcbei province may be divided into two morphological reaches.The upper reach is a braided river,about 100 km.from Huangbizhang to Shunzhe.The lower reach is a slightly meandering stream,80km.from Shunzhe to Xian—Cotmty,where it connects with Fuyan River,flowing down into BouhaiGulf.In braided river,the longitudinal bars are mostly composed of the followin gvertical beddings from bottom to top:lag deposits of poorly bedded gravels and sands,horizontal beddings of upper flow regime,large scale trough beddings,small scale trough beddings and parallel beddings of lower flow regims. Near the lateral margins of longitudinal bar,although most beddings of the vertical section are similar to those mentioned above sequence,yet instead of horizontal beddings of upper flow regime,large scale tabular cross beddings take place,indicating that they are formed by sandwave migration of relative lower flow regime.The average thickness of recent longitudinal bar deposits of braided course is very thin,only about 1.0 m.In slightly meandering stream,trenched profile sections show that two different vertical sequences of point bar accur.At the leeside of point bar,where flow is gentle,large scale trough beddings predominate,the whole section is similar to the fining-upward model of point bar deposits as stated by J.R.L.Allen(1970).whereas,at the stoss side of point bar,where flow is swift,large scale longitudinal cross beddings predominate,which consist of a bundle of cross beds in different directions,and no rhythmic variation of grain size appears in the vertical section.The average thicknees of recent point bar deposits is above 2.0 m.The sequential beddings of natural levee from bottom to top are:r2 small ripple bedding,r3 ripple bedding,r4 supperpose bedding,r3 ripple bedding,r2 small ripple bedding,r1 parallel bedding.They are the deposits along high river banks by relatively slow—moving flow during flood period.Beddings r2 to r4 and r3 to r1 represent the semicyles of upraizing and receding of flood respectively.