| 南海西南海域表层沉积物中微量元素Ba的地球化学特征 |
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| 引用本文： | 蔡观强,邱燕,彭学超,张玉兰,钟和贤.南海西南海域表层沉积物中微量元素Ba的地球化学特征[J].现代地质,2010,24(3). |
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| 作者姓名： | 蔡观强 邱燕 彭学超 张玉兰 钟和贤 |
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| 作者单位： | 1. 广州海洋地质调查局,广东,广州,510760
2. 同济大学,海洋地质国家重点实验室,上海,200092 |
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| 基金项目： | 国家自然科学基金项目 |
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| 摘 要： | 分析南海西南海域表层沉积物中微量元素Ba的地球化学特征,并探讨生物成因Ba的分布及其与表层海水生产力的关系。南海西南海域表层沉积物Ba总量的变化范围为398~1 270μg/g,平均值为851μg/g,从上陆坡到下陆坡,沉积物中的Ba含量逐渐增加;微量元素Ba主要赋存于陆源碎屑相和生物成因相中,且明显受到沉积环境水深和陆源物质输入的影响。生物成因Ba含量的变化范围为30.6~938μg/g,陆坡区和深海区平均值分别为495μg/g、349μg/g,占沉积物Ba总量的54%和51%,总体上,与沉积物Ba总量具有相对一致的分布特征。尽管研究区表层沉积物中Al、Ti成分为典型的陆源碎屑组分,但是,利用大陆上地壳Ba/Al比值和陆坡区沉积物回归分析获得的Ba/Al比值进行生物成因Ba的计算,过高地估算了沉积物中陆源Ba的含量;而采用页岩Ba/Ti比值来估算陆坡区表层沉积物中的生物成因Ba含量显得相对可靠。在深海区,利用经验的Ba/Al或Ba/Ti比值均不能获得有效的生物成因Ba值。因此,在获取沉积物中生物成因钡含量时,需结合各海区的特点选取合适的参数来扣除陆源Ba的含量。
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| 关 键 词： | 南海 生物成因Ba 陆源Ba 生物生产力 |
Geochemical Characteristics of Barium in Surface Sediments from the Southwestern Area of South China Sea |
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| CAI Guan-qiang,QIU Yan,PENG Xue-chao,ZHANG Yu-lan,ZHONG He-xian.Geochemical Characteristics of Barium in Surface Sediments from the Southwestern Area of South China Sea[J].Geoscience——Journal of Graduate School,China University of Geosciences,2010,24(3). |
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| Authors: | CAI Guan-qiang QIU Yan PENG Xue-chao ZHANG Yu-lan ZHONG He-xian |
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| Abstract: | The geochemical characteristics of barium in surface sediments from the southwestern South China Sea(SCS) are analyzed to investigate the distribution of biogenic barium(Babio) and its potential as a proxy for productivity in surface water.The total Ba content of the studied samples ranges from 398 μg/g to 1,270 μg/g,with an average of 851 μg/g,which is mainly concentrated in detrital materials and biogenic materials,and influenced by sedimentary environment and the input of detrital materials.The estimated biogenic Ba content ranges from 30.6 μg/g to 938 μg/g,and the averages of sediments from the upper slope and lower slope are 495 μg/g and 349 μg/g,which account for 54% and 51% respectively.In the southwestern area of the SCS,the total barium and biogenic barium in the sediments show a similarity in distribution,which is characterized by high Ba concentration in sediments from islet areas while low Ba concentration in deep sea area and upper continental slope.The Ba/Al ratio of upper continental crust and that of sediments from continental slope gained by regression analysis are used for calculating biogenic barium,and the results show that exorbitant detrital barium is given.Based on the Ba/Ti ratio of the shale(post-Archean Australian Shale),more reasonable biogenic barium can be estimated for the sediments in continental slope;however,the conventional Ba/Al or Ba/Ti ratios are not suitable for calculating the Babio in deep sea area.Therefore,more attention should be paid to when biogenic barium is used for paleoproductivity research in the SCS. |
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| Keywords: | South China Sea biogenic barium detrital barium productivity |
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