铜川地区11.4~1.5 ka B.P.期间黄土地球化学风化特征及其古气候意义
Characteristics of Geochemical Weathering of Loess in the Tongchuan Area during 11.4~1.5 ka B.P. and Its Paleoclimatic Implications

周家兴 ^1,2 吴利杰 ^1,2 ^* 于娟 ^2,3 杨丽君 ¹

文摘	通过对铜川剖面黄土-古土壤地层中常量元素和微量元素的地球化学特征进行分析,结合AMS-~(14)C年代学数据,利用Na/K值、CIA(化学风化指数)、A-CN-K三角图、Bc(退碱系数)、Ki(残积系数)、Rb/Sr值和Ba/Sr值等指标,探讨了该地区11.4~1.5 ka B.P.间黄土-古土壤地层的化学风化特征及其古气候意义。结果表明:(1)Na/K、CIA和A-CN-K三角图等分析指示铜川剖面11.4~1.5 ka B.P.间黄土-古土壤地层处于初等化学风化作用阶段。(2)Bc、Ki、CIA、Rb/Sr和Ba/Sr等指标的变化趋势同黄土-古土壤地层具有很好的对应性,较好的记录了铜川地区11.4~1.5 ka B.P.间的气候变化特征,可以将该地区的气候变化划分为4个阶段:11.4~10.2 ka B.P.气候寒冷干燥;10.2~9.1 ka B.P.温度逐渐上升,气候略温偏干;9.1~4.4 ka B.P.气候温暖湿润;4.4~1.5 ka B.P.气候逐渐转为冷干。(3)元素地球化学参数记录的铜川地区全新世最适宜期为9.1~6.0 ka B.P.,并且在6.0~5.0 ka B.P.期间存在次一级的气候恶化事件。
其他语种文摘	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, Na_2O/K_2O 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 Holocene optimum 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.
来源	地球与环境 ,2019,47(1):64-73 【核心库】
DOI	10.14050/j.cnki.1672-9250.2019.47.002
关键词	铜川剖面 ; 元素地球化学 ; 风化强度 ; 古气候
地址	1. 西北大学地质学系, 大陆动力学国家重点实验室, 西安, 710069 2. 中国地质科学院水文地质环境地质研究所, 石家庄, 050061 3. 中国地质大学(武汉)环境学院, 武汉, 430074
语种	中文
文献类型	研究性论文
ISSN	1672-9250
学科	地质学
基金	中国地质调查局中国地质科学院基本科研业务费 ; 中央级公益性科研院所基本科研业务专项基金
文献收藏号	CSCD:6428783