渭河阶地全新世土壤粒度成分高分辨率研究

High-solution Analysis on the Fraction of Holocene Soil on the Second Terrace of Weihe River

通过对渭河阶地全新世土壤的野外考察和粒度成分的高分辨率分析研究 ,揭示了该区域褐色土的成壤作用过程与季风气候变化的关系。研究表明渭河第二级阶地褐色土形成在全新世气候最适宜期 (85 0 0～ 310 0aB .P .) ,从 85 0 0aB .P .开始该土壤开始发育 ,老官台文化兴起。从 310 0aB .P .开始的气候干旱化和沙尘暴堆积形成了黄土L。层。

The soils on the terraces of Weihe River are the results of the deposit of Holocene sand dust storms and the environment evolution. These soils are the development base of the agricultural civilization for several thousand years in the Weihe River watershed. Therefore, many pedologists, experts in environment evolution and archaeologists research the soils from the different angles with the different methods and means. In this paper, the high solution analysis on the fraction of Holocene soil on the second terrace of Weihe River is carried out so as to reveal the monsoon evolution, influence of the deposit of sand dust storms on the formation process of the soil, and the relationship between the development of some important ancient cultures and the evolution of the resources and environment. The relationship between the formation process of drab soil and the monsoon climate change is revealed by the field investigation and the high solution analysis on the fraction of Holocene soil on a terrace of Weihe River. The analyzed results show that the drab soil on the second terrace of Weihe River formed in the period (8,500～3,100 a B.P.) of Holocene epoch under the most ideal climate conditions. The soil began to develop from 8,500 a B.P., and the Laoyitai culture was risen. The L 0 layer of the loess formed under the arid climate and the frequent occurrence of sand dust storms from 3,100 a B.P., i.e., Western Zhou Dynasty.