威海周边海域表层沉积物沉积环境分区与元素组成控制因素

Control factors of sedimentary dynamic environment zones and element composition of surface sediments in surrounding waters of Weihai

为深入理解黄海现代沉积作用和沉积环境,研究了威海周边海域表层沉积物的粒度、元素地球化学特征及其控制因素,并探讨了海域沉积动力环境。研究发现,粉砂粒级是表层沉积物中最重要的组分,由岸向海逐渐增加,研究区北部、东部及刘公岛南部海域粉砂含量普遍>60%;砂粒级组分含量由岸向海逐渐降低。依据沉积物粒度特征,研究区的沉积动力环境可以划分为5个区,由岸向海水动力逐渐减弱。近岸粗颗粒沉积物受河流以及海岸侵蚀影响,细颗粒物质来源于黄河,受到山东半岛沿岸流控制。表层沉积物大部分常微量元素分布特征受粒度控制,CaO主要受碳酸盐碎屑影响,控制Sr元素分布的主要因素是海洋生物沉积作用。K_(2)O、NaO、SiO_(2)、Ba等元素受物源控制,MnO_(2)除了受粒度控制影响外还受到氧化还原环境影响。

To gain a deeper understanding of modern sedimentation,sedimentary environment,and evolution in the Yellow Sea,the grain size,element geochemical characteristics,and the control factors of surface sediments in the waters around Weihai were analyzed,and the sedimentary dynamic environment discussed.We found that the silt is the major component in the sediments,and its amount gradually increases from shore to sea.The silt content in the northern,eastern,and southern waters of Liugong Island is generally more than 60%.The content of sand fraction decreases gradually from shore to sea.According to the grain size characteristics,the sedimentary dynamic environment in the study area can be divided into five zones or types;and water power gradually weakens from shore to sea.Coastal coarse-grained sediments are affected by river and coastal erosion,and fine-grained materials come from the Yellow River and are controlled by the coastal current around Shandong Peninsula.Most of the common trace elements in surface sediments are affected by particle size,CaO is mainly by carbonate debris,Sr by marine biological factor,K_(2)O,NaO,SiO_(2),Ba and other elements by provenance property,and MnO_(2) by particle size and oxidation state jointly.