近120年来高陵渭河河漫滩沉积物磁化率指示的气候变化

根据史料记载以及高陵渭河河漫滩沉积物共110个样品磁化率、粒度成分的测定分析,研究了近120年来,该地区沉积物在0～4.0 m深度上磁化率变化特征。结果显示,高陵渭河河漫滩磁化率随深度具有高低变化节律,整个剖面分6个阶段,第1,3,5阶段频率磁化率值高,第2,4,6阶段频率磁化率值低;沉积物磁化率与粒度成分有较好的相关性,表现为频率磁化率值低,沉积物粒度成分细,反之则反。磁化率反映了沉积时期水动力强弱变化,第1,3,5阶段对应洪水规模大的时期,指示沉积时水位高,水量大;第2,4,6阶段对应洪水规模小的时期,指示沉积时水位低,水量小。洪水规模的变化间接反映了该地区近120年来气候的波动变化特征。

Climate Change was Indicated by the Magnetic Susceptibility in Gaoling Weihe River Floodplain Near 120 Years

Based on analyzing the historic literature and the grain size and the susceptibility for 110 samples in the Gaoling Weihe river floodplain,the character of magnetic susceptibility was researched whthin the depth of 4.0m near 120 years.According to the analysis some conclusions have been summarized as follows: there is a obvious change rhythm of susceptibility in the Gaoling Weihe river and the profile is divided into 6 stages,the 1st,3rd,5th frequency dependent susceptibility are higher than the 2nd,4th,6th ones.The susceptibility and sediment have a good relation,which is the frequency dependent susceptibility lower and the size of sediment thiner.On the contrary the conclusion is opposition.At the same time the frequency dependent susceptibility reflact the flood changes.The flood depth and scale of the 1st,3rd,5th are biger than the 2nd,4th,6th.The flood also show the changes of climate near 120 years.