三亚近岸海域表层沉积物常量元素地球化学特征及其物源指示

Geochemical Characteristics and Provenance Implication of Major Elements in the Surface Sediments of the Sanya Offshore Area

为充分了解三亚海岸带的状况,对三亚近岸海域的331个站位表层沉积物的常量元素进行了分析。结果表明,研究区内沉积物常量元素组分以SiO_2,Al_2O_3,CaO为主。除SiO_2,CaO外,其余各常量元素组分含量(质量分数)均低于其各自在我国浅海沉积物中的丰度值。空间分布上,三亚近海表层沉积物中的常量元素基本遵循"元素的粒度控制律",Al_2O_3和与其密切相关的常量组分显示陆源细粒沉积物特征,SiO_2则表现出相反的特征。除"粒控效应"外,K_2O,MnO和有机碳在空间的分布还受其他因素影响,CaO的空间分布则主要受控于海洋生物作用。研究区物质来源应以附近的陆源碎屑物质为主,另外还有海洋生物及自生作用等其他物质来源。

In order to fully understand the status of the Sanya coastal zone,major chemical elements of 331 surface sediment samples taken from the Sanya offshore area are analyzed.The results show that SiO2,Al2O3 and CaO are dominant chemical components in the sediments of the study area.Except for SiO2 and CaO,the contents of other major elements are all lower than their abundance values in the sediments of the shallow seas of China.In the spatial distribution,the major elements in the surface sediments of the Sanya offshore area follow basically the“grain size control law of elements”.Al2O3 and the major elemental compositions closely related to it show the characteristics of terrestrial fine-grained sediments,whereas SiO2 shows an opposite character.Except for the“grain-size control effect”,the spatial distributions of K 2O,MnO and organic carbon are also influenced by other factors,of which the spatial distribution of CaO is mainly controlled by marine biological effect.The sources of the sediments in the study area are dominated by the terrestrial detritus from the nearby,followed by other sources such as marine biogenic and authigenic materials.