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本文利用X荧光光谱仪测定了象山港沉积物柱状样中常量元素Ti、K、Ca、Fe、Mn和微量元素Pb、Rb的含量。通过~(210)Pb定年,分析了象山港近百年来元素的沉积记录变化特征。结合沉积物粒径、有机碳、无机碳、总氮等理化参数,通过计算富集系数和主成分分析,探讨了沉积物中金属元素的物源和环境指示意义。研究结果表明:象山港沉积物中的金属元素Ti、K、Ca、Fe、Mn、Pb、Rb的含量分别为0.45%~0.52%、2.14%~2.58%、2.48%~3.13%、4.54%~5.83%、546×10~(-6)~868×10~(-6)、23×10~(-6)~37×10~(-6)、113×10~(-6)~130×10~(~(-6)),与中国其他近岸海域具有很好的可比性。象山港沉积物中的金属元素Ti、K、Ca、Fe、Mn、Rb主要来源于陆源碎屑物质,没有出现明显的富集;而沉积物中的Pb自1980年以来出现了富集现象,其含量在近年来可能受到了人类活动的影响。金属元素Ti、K、Fe、Mn、Rb、Pb易于在有机质含量丰富的沉积物中赋存,而Ca则以无机碳酸钙的形式赋存于象山港底质中。通过与百年来长江流域夏季降水变化的比较,发现陆源性金属元素的沉积记录异常与历史降水异常年份具有耦合性。
In this paper, the content of major elements Ti, K, Ca, Fe, Mn and trace elements Pb, Rb in the sediment column of Xiangshan Harbor were measured by X-ray fluorescence spectrometer. Through the dating of ~ (210) Pb, the variation of sedimentary records of elements in Xiangshan Port over the last century was analyzed. According to sediment particle size, organic carbon, inorganic carbon, total nitrogen and other physical and chemical parameters, enrichment coefficient and principal component analysis were calculated to discuss the significance of the source and environment of the metal elements in sediments. The results show that the contents of Ti, K, Ca, Fe, Mn, Pb and Rb in the sediments of Xiangshan Harbor are 0.45% -0.52%, 2.14% -2.58%, 2.48% -3.13%, 4.54% 5.83%, 546 × 10 ~ (-6) ~ 868 × 10 ~ (-6), 23 × 10 ~ (-6) ~ 37 × 10 ~ (-6), 113 × 10 ~ (-6) ~ 130 × 10 ~ (~ (-6)), which has good comparability with other coastal waters in China. The metal elements Ti, K, Ca, Fe, Mn and Rb in the sediments of Xiangshan Harbor are mainly derived from terrigenous clastic matter without obvious enrichment. However, Pb in sediments has been enriched since 1980, Its content in recent years may be affected by human activities. The metal elements Ti, K, Fe, Mn, Rb and Pb are apt to occur in the sediments rich in organic matter, whereas Ca is in the form of inorganic calcium carbonate in the sediment of Xiangshangang. By comparing with the summer precipitation change in the Yangtze River basin over the past 100 years, it is found that the sedimentary records of terrigenous metallic elements are coupled with the anomalous years of historical precipitation.