厦门湾沉积物元素地球化学的研究

【作者】 钱华；

【导师】 杨逸萍；

【作者基本信息】 厦门大学 ， 海洋化学， 2001， 硕士

【摘要】 本文首次较全面地研究厦门湾九龙江口、厦门西港和同安湾三个海区22个站位表层沉积物样中Al、Ba、Ca、Co、Cr、Cu、Fe、Li、Mg、Mn、Na、Ni、P、Sr、Ti、V、Zn共17种常、微量元素，并对沉积物中元素含量与分布的主要控制因素、赋存形态及分布特征进行了探讨。结果表明： 厦门湾表层沉积物中所研究的多数元素的丰度接近于中国近岸浅海沉积物及福建省土壤平均值，但与长江口、黄河口沉积物相比，元素Zn和Mn有不同程度的富集，而Ca、Sr明显贫化。 九龙江河口区Ca、Sr、Mg等元素含量沿九龙江入海方向逐渐增大；而Al、Fe、Cu、Co等则沿入海方向略呈降低趋势。厦门西港中多数元素的含量分布较为均匀。同安湾沉积物中元素Ba、Co、Cu、Ni、V含量分布相对均匀，元素Ca、Sr、Mg等沿着入海方向呈现增加的趋势。 根据R型聚类分析结果将厦门湾沉积物分为三组：Fe、Al、Cu、Zn等元素为代表的粘土矿物组，以Ca、Mg、Ba、Sr等碱土金属为代表的碳酸盐矿物组和受人为活动的输入影响较大的元素(如元素P等)组。不同站位的Q型聚类分析将厦门湾分为五个元素地球化学分区，即以Fe、Al、Zn、Cu等元素含量高值区为特征的九龙江河口湾区，以元素P含量高值区为特征的同安湾东嘴港区，Ca、Na、Ni等元素含量高值区为特征的同安湾浔江海区，Sr、Ba、Ti等元素含量高值区为特征的厦门湾南部海区和以Co、Cr等元素含量高值区为特征的厦门西港海区。 厦门湾表层沉积物中元素Fe、Ti、Al、Co、Cr、Cu、Li、Ni、P、Zn等主要赋存在残渣态中，而元素Ca、Sr、Mn等主要赋存于非残渣态中。按元素的残渣态所占比例由高到低排序，可得如下结果，Ti＞Al＞Ba＞Fe＞V＞Li＞Zn＞Cu＞Cr＞Ni＞Co＞P＞Sr＞Mn＞Na＞Ca。 厦门湾表层沉积物元素的赋存形态存在不同程度的空间差异。在九龙江河口区，多数元素在不同站位的赋存形态差异较大，而厦门西港和同安湾差异较小。Mn、P、Ca、Sr等元素赋存形态的空间差异较大，其余元素差异较小。 物质来源、沉积物粒度和水动力条件是厦门湾表层沉积物中元素含量、赋存形态和空间分布等地球化学特征的主要控制因素。更多还原

【Abstract】 Surface sediment samples collected from 22 stations in three regions of the Xiamen Bay, i.e., Jiulongjiang estuary, Xiamen Western Sea and Tongan Bay, were analyzed for both the major and trace elements(Al.. Fe.. Mn.. Ti.. Ca.. Mg.. Na.. Ba.. Co.. Cr.. Cu.. Li.. Ni.. P.. Sr.. V.. Zn) systemically, for the first time. The sedimentological and geochemical factors that controlled the contents, distribution patterns and the speciation of these elements were evaluated as well. The main results gained here were:Contents of most elements in the surface sediment samples from Xiamen Bay were similar with those of average coastal sediment of China and the soil of Fujian province, but were generally high in Zn and Mn, low in Ca and Sr, compared to those of changjiang estuary and huanghe estuary.Spatial distribution patterns of elements: the contents of Ca.. Sr.. Mg in Jiulongjiang estuary increased along the river towards the sea, while the distribution of Al.. Fe.. Cu.. Co showed an opposite trend. The majority of the elements in Xiamen Bay were unanimous in their distribution. The distributions of the elements in Tongan Bay exhibited two trends, Ba.. Co.. Cu.. Ni.. V had no obvious variety; while the contents of Ca.. Sr.. Mg increased from the inner part to the outer part (near the sea) of the bay.The sediment types in Xiamen bay could be divided into three groups by model R Cluster Analysis: Fe.. Al.. Cu.. Zn appeared to be enriched in mud deposits; alkaline earth elements Ca.. Mg.. Ba.. Sr wereIII7associated with the carbonate-rich sediments; P, however, did not match those two patterns but instead had a higher content in the sediments influenced by anthropogenic inputs heavily. Based on the regional distributions of elements and the hydraulic environments, the elements of sediments in Xiamen Bay could be divided into three distribution patterns and geochemical regions by model Q Cluster Analysis. The concentrations of elements near the Jiulongjiang estuary were characterized by high Fe~ Al.. Zn~. Cu; Dongzui harbor in Tongan bay had high content of P; high values of Ca.. Na.. Ni appeared in the Xunjiang of the Tongan Bay; the areas in the south of Xiamen Bay showed high values of Sr.. Ba.. Ti; the sediments of the Xiamen Western Sea had high Co.. Cr contents.A four-stage sequential extraction procedure for determination of the speciation of extractable element, proposed by the Commission of the European Communities Bureau of Reference (BCR), had been applied to the sediments in Xiamen Bay. The results obtained showed that the majority of the elements studied, such as Fe.. Ti.. Al.. Co.. Cr.. Cu.. Li.. Ni.. P.. Zn, in the sediment of Xiamen Bay, were predominate in the residual fraction. On the contrary, Ca.. Sr and Mn were similar, with the residual fraction being of lowest significance. They were extracted in the largest percentage in exchangeable and bound to carbonates fraction. The relative abundance in residual fraction for these element followed the order: Ti> Al> Ba> Fe > V> Li > Zn> Cu> Cr> Ni> Co > P> Sr> Mn> Na> Ca0The elements bound to different phases in Xiamen Bay behavedIvdifferently in the level of spatial distributions. The variations in element speciation along the Jiulongjiang estuary were considerably greater than those of Xiamen West Sea and Tongan Bay. Relative to the distribution of other element speciation, the elements, such as Mn~ P~. Ca~. Sr, showed more obvious variation.The sources, grain sizes and the currents were three major factors controlling the geochemical characteristics, such as the contents, speciation and spatial distribution patterns, of the surface sediments in Xiamen Bay.更多还原