现代黄河三角洲南部潮间带及附近海域沉积特征认识与分析

基于潮间带和浅海12个柱状样粒度、地球化学元素、210Pb同位素实测数据，结合河流年代特征、岸线历史变化等资料，参照前人关于沉积相和沉积速率研究成果，对现代黄河三角洲南部潮间带及莱州湾西部海域沉积特征进行了分析。根据剩余210Pb比活度信息，综合运用历史地理学方法、沉积环境判别公式和粒度曲线变化特征，初步认识了现代黄河三角洲南部潮间带地区具体沉积年代。对柱状样的数据进行分析后，运用相关特征值定量区分了沉积物的物源。结果表明:在潮间带这样不稳定的沉积环境下，210Pb_ex比活度阶段性倒置的分布模式虽然无法对年代进行连续标定，但可以在很大程度上指示沉积环境变化。现代黄河三角洲南部潮间带沉积物形成时间要远早于莱州湾西部，210Pb结合沉积环境判别函数、历史地理资料以及粒度特征可以将深度102 cm、80 cm、32 cm分别标定为1929年、1934年和1947年。广利河水系在深度20 cm范围内影响沉积环境。地球化学元素相关特征值分析显示:现代黄河三角洲南部潮间带沉积物风化程度介于黄河和莱州湾南岸之间，个别微量元素富集程度与莱州湾沉积物差异明显，就沉积环境而言，与现代黄河沉积物已有所不同。

Recognition and Analysis of Sedimentary Characteristics of the Southern Intertidal Area of Yellow River Delta and Adjacent Sea Area

Measured data for grain size,geochemical elements and²¹⁰Pb isotopes from 12 cores in the intertidal zone and shallow sea of the intertidal zone south of the Yellow River Delta and in the western area of Laizhou Bay,in combination with chronological characteristics of the rivers and historical changes of the shorelines,were used to analyze their sedimentary characteristics.The study referred to previously reported works on sedimentary facies and sediment deposition rates.Preliminary values for dates of the intertidal zone of the modern southern Yellow River Delta were calculated from the excess²¹⁰Pb profile(²¹⁰Pb_ex)using the methods of historical geography,sedimentary environment discrimination formulae and changes in the grain-size curve.The analysis of the data in the cores indicated that the provenance of the sediment differed in the number of relevant eigenvalues,suggesting that in an unstable sedimentary environment such as the intertidal zone,multi-stage inverted distribution of²¹⁰Pb_exdoes not continuously calibrate the age of the sediment.To a large extent,however,it indicates changes in the external sedimentary environment.The period of sediment formation in the southern intertidal zone of the modern Yellow River Delta was much earlier than in the western Laizhou Bay.The sedimentary environment discriminant function,together with historical geographical data and grain-size characteristics,indicates depths of 102 cm,80 cm and 32 cm in 1929,1934 and 1947,respectively.The Guangli River system has affected the sedimentary environment in depths up to 20 cm.Analysis of geochemical element-related characteristic values shows the degree of sediment weathering in this zone between the Yellow River and the southern bank of Laizhou Bay.The degree of enrichment of individual trace elements is obviously different from that in Laizhou Bay sediments,showing that the sedimentary environment differed from modern Yellow River sediments.