渤海湾西岸全新世最大海侵位置探讨——以天津市西南精武镇一带为例

Discussion of Maximum Holocene Transgression Location on the West Coast of the Bohai Bay: Taking the Jingwu Town Southwest of Tianjin as An Example

通过对位于天津西青区精武镇的小南河村西南H孔和潘楼村西PL孔2个钻孔做粘土混浊水电导率,结合贝类及有孔虫鉴定,区分了海相层和陆相层的界限,探讨了天津市西南全新世最大海侵的特征。结果表明:天津精武镇附近早中全新世以来经历了陆相-短暂的海陆过渡相-陆相的沉积过程,全新世最大海侵位置在H孔与PL孔之间,距现代海岸线大约57km。H孔的薄层海相层为全新世最大海侵期形成的海陆过度相沉积物的边缘。

The boundary between the marine facies and the continental facies is distinguished and the maximum Holocene transgression location is discussed by means of the measurement of conductivity of clayey turbid water and the identification of foraminifera and shellfish made for two boreholes, Borehole H and Borehole PL, which were respectively drilled southwest of the Xiaonanhe Village and west of the Panlou Village of the Jingwu Town, Xiqing District of Tianjin City. The results show that since the early Mid-Holocene the region around the Jingwu Town has experienced a sedimentary process of continental facies → short-lived marine - continental transition facies → continental facies. And the maximum Holocene transgression location in this region lies between Borehole H and Borehole PL, about 57Km away from the modern coastline of the western Bohai Bay. The thin layer of marine facies occurring in Borehole H could be the margin of the marine continental transition facies formed during the maximum Holocene transgression.