摘要
对黄土中埋藏古土壤的研究有过许多报道。但对黄土风化过程中元素的变化讨论则不多。笔者是在近年来对陕西洛川黄土剖面工作的基础上,讨论了不同类型古土壤中元素的含量与分布,古土壤剖面中元素的变化。并将古土壤的化学组成与黄土母质进行比较,进而论述了在古气候变迁的影响下,黄土剖面中元素迁移、积聚的地球化学特征。这对探讨黄土的堆积环境和生物气候条件的演变,以及地层划分等均有十分重要意义。
This paper deals mainly with the content and distribution of chemical elements in different types of paleosol in loessial section of Luochuan,and the geochemical characteristics of elements in their translocation or accumulation process during process of soil formation from loess to paleosol.Comparing with parent material(loess),the average contents of Al,Fe^(3+) and K of the paleosol are higher than those of loess;whereas the average contents of Ca,Fe^(2+) and Na are lower than those of loess.The contents of Al,Fe^(3+),K in paleosol profile increase from bottom upward,and the highest value appears in the argillic layer,but the CaCOcontent is lowest and caliche horizon is evident.It is found by t test that the contents of Ca,Al,Fe^(3+),K,Si,Ti,Mn,Zn,etc.were changed markedly,but the contents of Pb,Co,Ba were not changed evidently after the genetic process from loess to paleosol.In addition,it can be found from the analysis of relative values of eluviation and illuviation of oxides that the Fe_(2)O_(3),Al_(2)O_(3),K_(2)O,etc.were accumulating,but CaO,Na_(2)O were leaching relatively in pedogenetic process.The accumulation of Fe_(2)O_(3) and leaching of CaO are most obvious.At the same time,the contents of Zn,Cu,Mn,Ti,Ni,etc.in paleosol are higher than those in loessial parent material,and the content of Co in paleosol is lower than loessial parent material.The distribution of these elements in the profiles are also different.It is considered that with strengthening of the intensity of pedogenesis progressively the Sr/Ba value was decreasing,whereas the F/Cl value and leaching coefficient(SiO_(2)/RO+R_(2)O)and aluminization coefficient(Al_(2)O_(3)/Al_(2)O_(3)(Malan loess))etc.were increasing.The different types of paleosol reflect their difference in the intensity of weathering process in pedogenesis,which they had undergone and the difference of leaching and accumulation degree of elements also reflects the marks of paleoclimatic fluctuation for each warm-humid pedogenetic stage during loess deposition and evolution.
作者
孙福庆
文启忠
刁桂仪
余素华
Sun Fuqing;Wen Qizhong;Diao Guiyi;Yu Suhua(Institute of Geochemistry,Academia Sinica)
出处
《土壤学报》
1983年第2期101-111,共11页
Acta Pedologica Sinica
