西安临潼白庙剖面全新世黄土与环境变化

Study on the Relationship between Holocene Loess at Baimiao Profile and Environment Change in Lintong Region, Xi'an

西安临潼白庙剖面全新世发育了两层黄土与两层古土壤 ,通过对该剖面各层黄土与古土壤中微量元素Zn ,Ni,Cr,Co ,Ba ,Rb ,Sr的含量测定 ,研究了当时土壤发育的强弱和气候环境的变化。结果表明 ,其微量元素具有指示冬夏季风等环境变化的重要作用 ,反映了全新世以来该区发生过 4次较大的生物、气候环境的变化 ;古土壤代表的温湿期气候比现今明显 ,当时夏季风活动加强 ,但冬夏季风活动强度与持续时间相近 ,并非是夏季风占优势 。

The change of monsoon climate and the evolution of soil formation have become as the important contents in the research on the climatic environment change since the Holocene Epoch. The difference of the content of trace elements in loess is caused by the biological and climatic changes, eluviation, weathering, soil formation, etc. The Baimiao profile selected in this study is located at a place about 3 km west from Lintong County Town, it belongs to the warm temperate continental monsoon climate, the annual temperature and precipitation here are 13 ℃ and about 600 mm respectively. At the Baimiao profile 2 layers of Holocene loess and 2 layers of paleosol are developed. In this paper, the relationship between the soil formation and the climatic environment change is studied by measuring the content of trace elements including Zn, Ni, Cr, Co, Ba, Rb and Sr in the loess and paleosol at the profile. The results show that the content of trace elements in soil can reveal the monsoon and environment changes in this region at that time, that is there were 4 times of the violent biological and climatic environment changes; the warm humid climate represented by the paleosol at that time was obviously warmer and more humid and the monsoon occurred more frequently and strongly than that at present, but the climate when the loess developed was similar to that at present in the Xi'an region.