地理学报 ›› 2017, Vol. 72 ›› Issue (2): 279-291.doi: 10.11821/dlxb201702008

• 土地利用与环境变化 • 上一篇    下一篇

汉江上游黄土常量元素地球化学特征及区域对比

毛沛妮(), 庞奖励(), 黄春长, 查小春, 周亚利, 郭永强, 胡慧, 刘涛   

  1. 陕西师范大学旅游与环境学院,西安 710119
  • 收稿日期:2016-06-17 修回日期:2016-10-12 出版日期:2017-02-15 发布日期:2017-04-28
  • 作者简介:

    作者简介:毛沛妮(1989-), 女, 山西运城人, 博士生, 研究方向为资源开发与环境演变。E-mail: maopeini1989@126.com

  • 基金资助:
    国家自然科学基金项目(41271108, 41371029, 41471071);国家社会科学基金项目(14BZS070);中央高校基本科研业务费专项基金(GK201704014)

Chemical weathering characteristics and regional comparative study of the loess deposits in the upper Hanjiang River

Peini MAO(), Jiangli PANG(), Chunchang HUANG, Xiaochun ZHA, Yali ZHOU, Yongqiang GUO, Hui HU, Tao LIU   

  1. College of Tourism and Environmental Sciences, Shaanxi Normal University, Xi'an 710119, China
  • Received:2016-06-17 Revised:2016-10-12 Online:2017-02-15 Published:2017-04-28
  • Supported by:
    National Natural Science Foundation of China, No.41271108, No.41371029, No.41471071;National Social Science Foundation of China, No.14BZS070;The Fundamental Research Funds for the Central Universities, No.GK201704014

摘要:

本文对汉江上游黄土的常量元素含量及相关地球化学参数CIA、Na/K、淋溶系数、退碱系数、残积系数等进行了系统分析。结果显示:① 汉江黄土的主要化学成分为SiO2、Al2O3和Fe2O3,三者含量总和达767.3 g/kg;常量元素含量大小排序为SiO2>Al2O3>Fe2O3>K2O>MgO>Na2O>CaO。风化成壤过程中Na、Ca、Mg、Si发生不同程度的迁移淋溶,而Fe、Al、K相对富集。② 其风化成壤强度呈现从马兰黄土L1→过渡性黄土Lt→古土壤S0逐渐升高、全新世黄土L0又降低的规律,记录了该区域气候经历了末次冰期(55.0-15.0 ka BP)冷干、早全新世(15.0-8.5 ka BP)增温增湿、中全新世(8.5-3.1 ka BP)达到最暖湿,晚全新世(3.1-0.0 ka BP)降温变干的演变过程。③ 汉江黄土与洛川、巫山、下蜀黄土的元素组合特征高度一致,不同地区常量元素(CaO除外)含量十分接近且UCC标准化值变幅均小于0.25,这暗示了它们风化之初具有相似的风成沉积基础;但不同区域黄土的化学风化强度差异明显,大致呈现洛川黄土<汉江黄土<巫山黄土<下蜀黄土的趋势,与中国现代季风气候的空间变化规律相吻合,即不同地区黄土风化程度差异主要是东亚季风变化影响的结果。

关键词: 黄土, 常量元素, 风化程度, 汉江上游, 区域对比

Abstract:

Field investigations were carried out along the upper reaches of the Hanjiang River, a major tributary of the Yangtze River in China. Three loess profiles on the first river terrace were selected for a detailed study. The characteristics of major elements and chemical weathering were analyzed systematically. Results are shown as follows. (1) The major elements are dominated by SiO2, Al2O3 and Fe2O3, the total average content of which is 767. 3 g/kg, in the loess profiles of the region. The contents of the major elements are ranked in the following order: SiO2>Al2O3>Fe2O3>K2O>MgO>Na2O>CaO. The elements Na, Ca, Mg and Si are leached to different degrees and Fe, Al and K relatively enriched in the chemical weathering processes. (2) The weathering and pedogenic intensity was the weakest in the Malan loess L1, increased slightly in the transition loess Lt, became the strongest in the paleosol S0, and decreased again in recent loess L0. The results reveal that the climate was cold-dry in the Last Glacial (55.0-15.0 ka BP), turned into warm-wet gradually in the Early Holocene (15.0-8.5 ka BP), became the warmest and wettest in the Mid-Holocene Climate Optimum (8.5-3.1 ka BP), and turned into cool and dry in the Late Holocene (3.1-0.0 ka BP). (3) Based on the comparison with Luochuan, Wushan and Xiashu loess, we can find that the major elemental compositions and the UCC-normalized patterns of the loess are similar with those of Luochuan, Wushan and Xiashu loess to a higher degree, suggesting a similar sedimentary background of aeolian loess. But the chemical weathering intensity of these loess deposits changes significantly in different parts of China, with the sequence?of Luochuan loess < loess in the Hanjiang River < Wushan loess

Key words: loess, major element, chemical weathering degree, upper Hanjiang River, regional comparison