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中国沙漠 ›› 2011, Vol. 31 ›› Issue (4): 862-867.

• 古气候与环境演变 • 上一篇    下一篇

关中东部全新世黄土古土壤序列常量元素地球化学特性研究

丁 敏1,2,3, 庞奖励1,2*, 黄春长1, 李艳华1, 王丽娟1, 牛晓露1   

  1. 1.陕西师范大学 旅游与环境学院, 陕西 西安 710062; 2.中国科学院地球环境研究所黄土与第四纪地质国家重点实验室, 陕西 西安 710075; 3.泰山学院 旅游与资源环境学院, 山东 泰安 271021
  • 收稿日期:2010-11-05 修回日期:2010-12-12 出版日期:2011-07-20 发布日期:2011-07-20

Geochemical Characteristics of Major Elements in Holocene Loess-Paleosol Sequence in the Eastern Guanzhong Basin, Shaanxi, China

DING Min1,2,3, PANG Jiang-li1,2, HUANG Chun-chang1, LI Yan-hua1, WANG Li-juan1, NIU Xiao-lu1   

  1. 1.College of Tourism and Environmental Sciences, Shaanxi Normal University, Xian 710062, China; 2.State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, CAS, Xian 710075, Shanaxi, China; 3.College of Tourism and Environmental Sciences, Taishan University, Taian 271021, Shandong,China
  • Received:2010-11-05 Revised:2010-12-12 Online:2011-07-20 Published:2011-07-20

摘要: 对关中盆地东部全新世黄土-古土壤序列(YHC剖面)常量元素分析,发现:YHC剖面化学组成以SiO2、Al2O3和CaO为主,三者平均含量的总和达774.1 g·kg-1,元素含量SiO2 >Al2O3>CaO>Fe2O3>MgO>Na2O>K2OTiO2; 相对黄土L1,Ca、Na、Mg在S0中相对迁移,且Ca、Na淋溶强烈,K、Fe、Al在S0中相对轻微富集; 关中平原东部风化程度弱,处于较弱的脱Ca、Na初级风化阶段(并且可能在沉积源区就已经发生),伴有碳酸盐的淋溶。CIA等揭示的YHC剖面各层的风化顺序S0>Lt>L0>TS>L1UCC,与关中西部扶风和黄土高原中部庄浪相比,关中平原东部的风化程度居中。CIA对气候的响应灵敏,揭示出早全新世风化渐强气候变暖,中全新世风化最强气候暖湿,晚全新世以来风化程度骤然减弱气候恶化,对次一级的气候事件也有反映。

关键词: 常量元素, 黄土-古土壤序列, 全新世, 关中盆地

Abstract: Based on the field investigation, sampling and major elements analysis in a Holocene loess-paleosol profile in the eastern Guanzhong basin of Shaanxi Province, the major element geochemical characteristics are discussed. The results show that the content of major elements is mainly made of SiO2, Al2O3and CaO, and their total concentrations is up to 77.41%, the element content is followed by SiO2>Al2O3>CaO>Fe2O3>MgO>Na2O>K2O>TiO2. Relatively to loess L1, Ca, Na have strongly leached out of the paleosol S0 but K, Fe, Al relatively enriched in the S0.The results indicate that the profile has experienced a incipient stage of chemical weathering in dust source regions, characterized by the decomposition of plagioclase which caused the depletion of mobile elements Na and Ca. The post-depositional chemical weathering is characterized by carbonate dissolution.The CIA index (reflecting chemical weathering density)responses to climate change sensitively, and it reveals that climate become warmer gradually in early Holocene, the most warm and humid in Mid-Holocene, sudden dryer and cooler in the Late Holocene in the study area, and sub-level weather events and human activities are also reflected.

Key words: major elemental, loess-paleosol, Holocene, Guanzhong basin

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