虎头梁砾石钙膜的研究与意义  

THE DISCOVERY OF GRAVEL CALICHE AT HUTOULIANG AND ITS SIGNIFICANCE

作　　者：任庆龙 马蒙[1] 谭利华[1] 李容全[1] 熊建国[2] 

机构地区：[1]北京师范大学地理学与遥感科学学院,北京100875 [2]北京大学城市与环境学院,北京100871

出　　处：《北京师范大学学报（自然科学版）》2014年第3期298-301,共4页Journal of Beijing Normal University(Natural Science)

基　　金：国家自然科学基金资助项目(J1103403)

摘　　要：我们在河北阳原虎头梁的冻融褶皱砾石层顶部发现一层钙膜砾石.通过对钙膜明暗度曲线分析及其与氧同位素曲线的对比研究，结合14 C测年结果，得出虎头梁钙膜的发育时间介于40~21 ka BP之间.砾石钙膜的发育代表着曾经地下水位停留在此，说明在泥河湾古湖消亡后，桑干河下切初始阶段有过一段较长时间的停顿.根据河流阶地的高差及年龄数据，计算桑干河虎头梁段在21~7.6 ka BP、7.6~3.1 ka BP和3.1~0 ka BP 3个阶段的河流下切速率分别为1.8、4.2、2.9 mm·a^-1.这种下切速率的差异应主要是由气候变化造成的.Caliche lamination contains abundant paleo-climate and age information,shades of caliche micro-lamination record climate change.A layer of caliche gravel was found in the upper freeze thaw folds gravel layer at Hutouliang,Hebei province.The caliche was dated from 40-21 ka BP by comparison of characteristic curve of caliche lamination and characteristic curves of deep-sea oxygen isotope,and by 14 C dating.The development of gravel caliche expressed that groundwater level had stay at here at one time,and this indicated downcutting of Sanggan river had a longer pause in the initial stage after the ancient lake’s extinction.It was calculated that the downcutting rate were 1.8,4.2 and 2.9 mm·a^-1 in 21~76 ka BP,7.6~3.1 ka BP and 3.1~0 ka BP stages according to elevation differences and age data of river terraces.The difference in downcutting rate should be mainly caused by climate change.

关 键 词：虎头梁 钙膜砾石 河流地貌演化 下切速率 

分 类 号：P588.212.5[天文地球—岩石学]