ZHOU Jiaxing1,2, WU Lijie1,2,*, YU Juan2,3, YANG Lijun1
(1. State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, xi’an, 710069, China;
2. The Institute of Hydrogeology and Environmental Geology, CAGS, Shijiazhuan, 050061, China;
3. School of Environment Studies, China University of Geosciences, Wuhan 430074, China)
Abstract: The major and trace elements contents in loess-paleosoil strata were analyzed to characterized geochemical weathering along a profile of Tongchuan during 11.4~1.5 ka B.P. and its paleoclimatic implications were discussed in terms of chronologic dating, Na2O/K2O ratio, chemical index of alteration (CIA), A-CN-K diagram, return coefficient (Bc), eluvial coefficients (Ki), Rb/Sr ratio and Ba/Sr ratio. The results showed that: (1) the chemical weathering in loess-paleosoil strata of Tongchuan profile during 11.4~1.5 ka B.P. was relatively weak; (2) variation trends of Bc, Ki, CIA, Rb/Sr and Ba/Sr ratios corresponded well with the loess-paleosoil strata, which recorded climate changes well during 11.4~1.5 ka B.P. in the Tongchuan region, the major climate changes could be divided into four stages: the climate was very dry and cold during11.4~10.2 ka B.P., the climate was slightly warm and dry with temperature rising gradually during 10.2~9.1 ka B.P., the climate was warm and humid during 9.1~4.4 ka B.P., the climate turned to cold and dry gradually during 4.4~1.5 ka B.P.; (3) the most suitable period of Holocene in Tongchuan was in 9.1~6.0 ka B.P. and a climatic event of cold fluctuation during 6.0~5.0 ka B.P. was recorded according to records of elemental geochemical parameters.
Key words: Tongchuan; element geochemistry; weathering intensity; Paleoclimatic
EARTH AND ENVIRONMENT Vol.47, No.1, Tot No.327, 2019, Page 64-73