渤海海峡表层沉积物常量元素分布特征及其地质意义

DISTRIBUTION OF MAJOR ELEMENTS IN SURFACE SEDIMENTS OF BOHAI STRAIT AND ITS GEOLOGICAL SIGNIFICANCE

对采自渤海海峡北部海域35个站位表层沉积物进行常量元素分析,结果表明,研究区内表层沉积物常量元素主要由SiO2、Al2O3、Fe2O3、CaO、K2O、Na2O和MgO组成,约占沉积物总量的94.85%;其中SiO2、Al2O3和CaO的含量最高,平均含量分别达到70.44%、10.03%和3.96%,表明沉积物主要来源于陆源碎屑和黏土组分,其次是生物碎屑组分。SiO2与Mz呈较强负相关关系,在空间上分布与粗粒沉积物分布区相一致;Al2O3、Fe2O3、MgO、P2O5、TiO2在空间上分布相似,与细粒沉积物分布区相一致;此外,Al2O3、Fe2O3、MgO、Na2O、TiO2 5种常量元素之间呈明显的正相关关系,说明其分布受控因素较为相近。常量元素相关性和R型因子分析表明,研究区内常量元素可划分为3类,第1类包含了SiO2、Al2O3、Fe2O3、MgO、MnO、P2O5、TiO2组成,代表了陆源碎屑沉积;第2类主要由CaO、Na2O组成,代表了海洋生物沉积作用;第3类K2O可能代表了海洋化学作用。

The major elements of surface sediments in the northern Bohai Strait,according to the analyzing results of the samples collected from 35 stations,mainly consist of SiO2,Al2O3,Fe2O3,CaO,K2O,Na2O and MgO,which account for more than 94.85%of the total.SiO2,Al2O3 and CaO dominate on average of 70.44%,10.03%and 3.96%,respectively,suggesting the sediments of siliceous clasts and clays predominated by aluminosilicate minerals.SiO2 is strongly negatively correlated with Mz,and their spatial distribution is consistent with coarse-grained sediments.Al2O3,Fe2O3,MgO,P2O5 and TiO2 are similar in spatial distribution and consistent with that of fine-grained sediments.Moreover,there are obvious positive correlations among Al2O3,Fe2O3,MgO,Na2O and TiO2,indicating that their distribution is controlled by similar factors mentioned above.The correlation of major elements and R-factor analysis show that the major elements in the study area can be divided into three categories.The first category includes SiO2,Al2O3,Fe2O3,MgO,MnO,P2O5,and TiO2,representing terrigenous clastic deposits;the second category mainly consists of CaO and NaO,representing marine biogenous sediments;and the third category of K2O may suggest the impact of marine authigenic sediment.