厦门近海表层沉积物结构特征及物源初探

为研究厦门近海海域表层沉积物的结构特征、组成及来源,于2010年7月采集厦门湾表层沉积物,综合粒径分析、X射线衍射、扫描电镜等方法对沉积物进行表征。粒径分析的结果表明,沉积物的主体粒径在80μm附近,且有明显的次粒级峰,并以粗颗粒的主体粒级峰占有优势。研究的沉积物类型主要有三种,砂质粉砂、粉砂质砂和砂-粉砂,其中砂质粉砂是分布最广泛的沉积物类型区域沉积物,其含量达90%以上;而粘土含量以背景点鸡屿岛为最高,达到11.97%。X射线衍射分析表明,沉积物中优势轻矿物为石英、高岭石,部分区域含有石墨及一些零星分布的伊利石、海绿石和斜绿泥石。这些矿物组成显示了厦门湾海域表层沉积物具有较好的亲陆性,同时,其组成也受到了涨潮流的较大影响。沉积物形貌形态的研究发现,厦门湾沉积物组分较为复杂,其中含有多种藻类及其碎片(主要为硅藻)、矿物颗粒(高岭石)及未知名碎片;形状主要有孔状结构、层叠状结构、长条片状和不规则的六边形块状等。

Structural Characteristics and Sources of the Surface Sediments in Xiamen Coast

In order to study the structural characteristic,composition and source of the sediment in Xiamen coastal waters,the surface sediment in Xiamen Bay was collected in July,2010,and the samples were comprehensively analyzed by particle size analysis,X-ray diffraction,scanning electron microscopy and other methods.The results of the particle size analysis showed that the main diameter of the sediment was near 80 μm,with a pronounced secondary pea.There are three main types of sea sediments(sandy silt,silty sand,and sand-silt) and sandy silt is the most widely distributed type,which the content of the silt-sand at all study areas was nearly 90%,while the clay content was highest at the background point and reached to 11.97%.The X-ray diffraction analysis showed that the dominant light minerals in sediments were Quartz,Kaolinite;some areas contained Graphite.Illite,Glauconite and Clinochlore also had been found in some areas accidentally.The mineral composition showed the surface sediments had a good pro-land,meanwhile,it was affected by the flood current.While,the morphology study found that the composition of the sediments at the study areas were complex,containing a variety of algae and debris(mainly diatoms),minerals(kaolinite) and unknown debris.Cavernous structure,stack-like structure,long flake and irregular hexagon were the main shapes in these sediments.