| 从岩石到土壤再到水系沉积物：风化过程的岩性地球化学基因 |
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| 引用本文： | 严桃桃,吴轩,权养科,龚庆杰,李晓蕾,王萍,李睿堃.从岩石到土壤再到水系沉积物：风化过程的岩性地球化学基因[J].现代地质,2018,32(3):453. |
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| 作者姓名： | 严桃桃 吴轩 权养科 龚庆杰 李晓蕾 王萍 李睿堃 |
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| 作者单位： | 1中国地质大学(北京) 地质过程与矿产资源国家重点实验室，北京100083；
2中国地质调查局 发展研究中心，北京100037；3公安部 物证鉴定中心，北京100038 |
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| 基金项目： | 国家自然科学基金重点项目(41230311)；公安部物证鉴定中心协同创新工作项目(2016XTCX04)；中央高校基本科研业务费(2-9-2017-221)。 |
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| 摘 要： | 不活动元素的稳定性使得风化岩石、土壤和水系沉积物等风化产物能够保留新鲜母岩的元素特征，它们之间的含量变化趋势有可能从母岩传递到其风化产物中，这类似于生物学中基因遗传。仿照生物学中基因的特性提出了地球化学基因的概念及其构建方法，为了比较地球化学基因的相似程度进而提出基因相似度的概念及其计算方法。以风化过程中11种不活动元素为例，基于中国酸性岩、中性岩、基性岩的元素丰度数据构建了表征岩石及其风化产物地球化学特性的岩性地球化学基因，其元素序列为：Al2O3→SiO2→P→Ti→La→Fe2O3→Th→Zr→Nb→Y→U。利用豫西熊耳山地区安山岩风化剖面、残坡积—沟系土剖面、化探详查水系沉积物和区域化探水系沉积物4种比例尺尺度的样品对构建的岩性地球化学基因进行了检验，结果发现岩性地球化学基因在风化过程中具有很好的遗传性(从岩石到风化产物)和继承性(从土壤到其源岩)，利用岩性地球化学基因可以对土壤样品进行物源示踪。源自同一母岩的水系沉积物和土壤之间在岩性地球化学基因方面具有很好的相似性(同源风化产物之间)。基于中国区域化探水系沉积物调查数据，可以构建岩性地球化学基因库来对岩石及其风化产物样品进行溯源分析，在地质、环境、法庭等科学领域具有潜在应用前景。
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| 关 键 词： | 不活动元素 地球化学基因 基因相似度 岩性地球化学基因 风化作用 |
Heredity,Inheritance and Similarity of Element Behaviors Among Parent
Rocks and Their Weathered Products: A Geochemical Lithogene |
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| YAN Taotao,WU Xuan,QUAN Yangke,GONG Qingjie,LI Xiaolei,WANG Ping,LI Ruikun.Heredity,Inheritance and Similarity of Element Behaviors Among Parent
Rocks and Their Weathered Products: A Geochemical Lithogene[J].Geoscience——Journal of Graduate School,China University of Geosciences,2018,32(3):453. |
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| Authors: | YAN Taotao WU Xuan QUAN Yangke GONG Qingjie LI Xiaolei WANG Ping LI Ruikun |
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| Institution: | 1State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing100083, China；
2Center for Development and Research, China Geological Survey, Beijing100037, China；
3Institute of Forensic Science, Ministry of Public Security, Beijing100038, China |
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| Abstract: | Relative behaviors of immobile elements during weathering are usually stable from rock to its weathered products. The stability of these relative behaviors is similar to the genetic inheritance in biology. The term of geochemical gene is proposed here to describe the stability of relative variations in contents. The geochemical gene is coded as a sequence of immobile elements. Furthermore, similarity of gene is also proposed and calculated to evaluate the degree of consistency between samples in geochemical gene. Eleven immobile elements are selected to code the geochemical gene based on their abundances in the acidic, intermediate and basic rocks in China, and the sequence of these immobile elements is Al2O3→SiO2→P→Ti→La→Fe2O3→Th→Zr→Nb→Y→U. This geochemical gene is presented to characterize the geochemical attributes of the acidic, intermediate and basic rocks in China, and is therefore called geochemical lithogene in terminology. Geological materials with four scales sourcing from the same andesite of Xionger Group in western Henan Province, China are selected to test the validity of the geochemical lithogene. The results from the vertical weathering profile developed over the andesite indicate a well heredity from the fresh rock to its weathered products and a well inheritance from the top soil to its sources with different weathering degrees evaluated on WIG. The results from the lateral surficial soil profile, areal stream sediment surveys with a scale of 1∶50,000 and 1∶200,000 developed over the andesite outcrops indicate a well similarity among the soils and stream sediments sourced from the same parent rock in geochemical lithogene. A geochemical lithogene database may be constructed on the database of regional geochemical survey and may play an important role in the scientific fields such as basic geology, environmental survey, and forensic geochemistry. |
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| Keywords: | immobile element geochemical gene similarity of gene geochemical lithogene weathering |
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