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现代地质 ›› 2018, Vol. 32 ›› Issue (05): 1031-1041.DOI: 10.19657/j.geoscience.1000-8527.2018.002

• 应用地球化学 • 上一篇    下一篇

风化过程中硒背景值的定量表征

李金哲1(), 龚庆杰1(), 刘亚轩1,2, 严桃桃1, 李睿堃1   

  1. 1.中国地质大学(北京) 地球科学与资源学院,北京 100083
    2.中国地质科学院 地球物理地球化学勘查研究所,河北 廊坊 065000
  • 收稿日期:2017-12-14 修回日期:2018-05-03 出版日期:2018-10-10 发布日期:2018-11-04
  • 通讯作者: 龚庆杰,男,博士,教授,博士生导师,1972年出生,地球化学专业,主要从事地球化学教学与科研工作。Email:qjiegong@cugb.edu.cn
  • 作者简介:李金哲,男,博士研究生,1990年出生,地球化学专业,主要从事勘查和应用地球化学研究工作。Email:lijinzhe912@sina.com
  • 基金资助:
    中央高校基本科研业务费专项(2-9-2017-221)

Quantitative Description of the Geochemical Background Value of Selenium During Weathering Based on the Certified Reference Materials in China

LI Jinzhe1(), GONG Qingjie1(), LIU Yaxuan1,2, YAN Taotao1, LI Ruikun1   

  1. 1. School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
    2. Institute of Geophysical and Geochemical Exploration, Chinese Academy of Geological Sciences, Langfang, Hebei 065000, China
  • Received:2017-12-14 Revised:2018-05-03 Online:2018-10-10 Published:2018-11-04

摘要:

硒是人和动物必需的微量元素,基于58件标准物质的化学风化指标和硒的认定值,采用微量元素地球化学背景值的经验方程形式拟合得到表征全国范围内硒背景值的经验方程:lgc=0.822×(1.2-WIG/100)-1.061×lg(K2O/SiO2)-2.704,式中c为Se的含量(单位为μg/g),风化指标WIG的变化范围为4.3~111.6,风化指标K2O/SiO2变化范围为0.020~0.137。该方程所表征的是样品因风化程度不同所呈现出的硒地球化学背景值,风化程度强的样品总体上具有较高的Se地球化学背景值。将该经验方程式在广东河台和广东南昆山两个研究区进行应用,认为寻找富硒区应当优先将风化程度较强的地区视为备选区,依据全国区域化探扫面数据可以方便地确定风化程度较强的地区。在环境质量评价中可以利用Se实测值确定足硒和富硒区,利用实测值扣除背景值获得的元素含量剩余值可以有效确定残积层土壤下伏的足硒和富硒岩石,即依据全国多目标地球化学调查数据可以有效地确定足硒和富硒地质体(残积层土壤及其下伏岩石)的分布区。广东南昆山岩体中西部的岩石应属于足硒和富硒地质体。

关键词: 标准物质, 地球化学背景值, 化学风化指标, 河台, 南昆山, 广东省

Abstract:

The behavior of selenium, an important trace element for human and animal in environmental geochemistry, is described quantitatively based on the components of 58 certified reference materials collected as rocks, soils or stream sediments in China. The description equation on the relationship between the selenium contents and the corresponding chemical weathering indices is fitted as lgc=0.822×(1.2-WIG/100)-1.061×lg(K2O/SiO2)-2.704, where c is the content of selenium in μg/g, the value of WIG varies from 4.3 to 111.6, and the value of K2O/SiO2 varies from 0.020 to 0.137. This equation can be used to describe the geo-chemical background values of selenium resulted from different weathering degrees in rocks, soils, and stream sediments. Samples with strong weathering degrees have higher values of the selenium geochemical backgrounds commonly. The equation is applied to two districts of Hetai and Nankunshan in Guangdong Province, China. The results tell us that the areas with strong weathered geological bodies can be viewed as the candidates to find the areas with plentiful or rich selenium contents. The areas with plentiful or strong weathered geological bodies can be found feasibly based on the data of the Regional Geochemistry-National Reconnaissance (RGNR) project. In the soil evaluation on environmental quality, the plentiful or rich selenium areas can be assessed by the analyzed values of selenium. Furthermore,residual values which are the deduction results of geochemical background values from their analyzed values can be used to determine the plentiful or rich selenium geological bodies underlying the weathered materials. In other words, the geological bodies with plentiful or rich selenium which are underlying the weathered soils can be determined feasibly based on the data of the Multi-Purpose Regional Geochemical Survey project. The case study on the Nankunshan district indicates that the middle and west part of the Nankunshan pluton must be plentiful or rich in selenium.

Key words: certified reference material, geochemical background value, chemical weathering index, Hetai, Nankunshan, Guangdong Province

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