地学前缘 ›› 2010, Vol. 17 ›› Issue (3): 233-241.

• 论文 • 上一篇    下一篇

中国东部地带表土稀土元素的地球化学特征

杨恬, 朱照宇, 吴翼, 邱世藩, 饶志国, 韩江伟   

  1. 1中国科学院 广州地球化学研究所 边缘海地质重点实验室, 广东 广州 510640
    2中山大学 地理科学与规划学院, 广东 广州 510275
  • 收稿日期:2009-07-05 修回日期:2010-01-09 出版日期:2010-05-15 发布日期:2010-06-18
  • 作者简介:杨恬(1980—),女,博士后,主要从事全球变化与地球化学方面的研究。
  • 基金资助:

    国家自然科学基金项目(40672121,40872111);国家重点基础研究发展计划“973”项目(2004CB720204)

 Rare earth elements geochemistry in topsoils from the eastern part of China.

YANG  Tian, SHU  Zhao-Yu, TUN  Yi, QIU  Shi-Fan, RAO  Zhi-Guo, HAN  Jiang-Wei   

  1. 1Key Laboratory of Marginal Sea Geology, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China
    2School of Geography and Planning, Sun YatSen University, Guangzhou 510275, China
  • Received:2009-07-05 Revised:2010-01-09 Online:2010-05-15 Published:2010-06-18

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摘要：

对中国东部从黑龙江省到海南省的纵向大断面50个表土样品的稀土元素(REE)含量进行了测定,结果显示其平均含量高于中国土壤和世界土壤的平均值;其稀土元素组成特点表现为轻稀土(LREE)富集,重稀土(HREE)亏损,Eu的负异常和Ce的正异常;未发现稀土元素总量∑REE和轻重稀土比值∑LREE/∑HREE随纬度或年均温度、年降水量有明显的地带性规律变化;δCe值的分布特征显示在气候达到南亚热带北热带地区的湿热程度及风化强度时,表土才会出现显著的Ce正异常;在Ce/Eu对Eu/Sm图解上不同母岩类型的表土参数差异明显,尤其是玄武岩发育的表土与中酸性岩石和沉积岩发育的表土之间具有明显差异。本研究表明,中国东部表土的稀土元素分布特征没有明确的气候带示踪意义,而主要具有成土母质类型示踪意义;δCe值的显著正异常可以示踪南亚热带热带气候;由于影响因素复杂,各种特征参数的细微变化对沉积物成因、物源区以及区域气候的指示意义尚待积累更多的数据并参考其他环境指标才能做出正确判断。

关键词: 稀土元素, 表土, 环境示踪, 中国东部

Abstract:

Fifty topsoil samples collected from the eastern part of China from Heilongjiang to Hainan Province have been analyzed for rare earth elements (REEs). The results indicate that the average contents of rare earth elements in topsoils from the eastern part of China are much higher than those in China as well as in the world; it is characterized by LREEenrichment and HREEdepletion with negative δEu and positive δCe; noticeable positive δCe values have been found in the soils from south subtropics and tropics with hothumid climate and intense weathering process; the plot of Ce/Eu against Eu/Sm is proved to be useful to distinguish different parent rocks of topsoil. This study suggests that the distribution characteristic can be used as a tracer for parent rock of soils, but not an index for climatic zone; δCe value can be used as an index of hothumid climate. However, it is currently not well known how the factors such as sedimentary origin, source area and local climate affect the distribution of rare earth elements. More data would be necessary to answer this question.

Key words:  rare earth elements, topsoil, environmental trace, the eastern part of China

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