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苏北盆地是一个以箕状断陷为特点的复合型沉积盆地。文章根据2004年夏采集的苏北盆地宝应钻孔(BY1)97m沉积物的124个样品11种常量元素S iO2,A l2O3,TiO2,Fe2O3,MgO,MnO,CaO,K2O,Na2O,P2O5和SO2的地球化学特征分析,探讨了海相沉积环境与陆相沉积环境的元素分布特点、成因、相互之间的联系和物质来源。根据沉积物常量元素含量的垂向变化,结合沉积相、岩性特征、有孔虫分析、古地磁及14C定年,分析了苏北盆地2.58M a以来不同阶段海陆交互作用下的常量元素变化特点,反映了苏北平原在第四纪曾经历了4次海水淹覆,海-陆交互堆积作用明显,经滨浅海→泻湖→湖泊→洼地,最后由河流冲积物覆盖成陆。
Subei Basin is a composite sedimentary basin characterized by a half-graben faulting. In this paper, 11 kinds of elemental elements S iO2, Al 2 O 3, TiO 2, Fe 2 O 3, MgO, MnO, CaO, K 2 O, Na 2 O, P 2 O 5 and SO 2 from 124 samples of 97 m sediments of the Baoying boreholes (BY1) Geochemical characteristics of the marine sedimentary environment and terrestrial sedimentary environment of the elemental distribution characteristics, causes, mutual relations and material sources. According to the vertical variation of the elemental contents of the sediments, combining with the sedimentary facies, lithology, foraminifera analysis, paleomagnetism and 14C dating, the variation characteristics of the major elements under the interaction of land and sea at different stages of the Subei Basin since 2.58Ma are analyzed , Reflecting that the Subei Plain experienced four times of seawater flooding in the Quaternary. The interaction between the sea and the land was obvious. After shallow water → lagoons → lakes → depressions, it was finally covered by the river alluvial cover.