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    方晶, 王福, 商志文, 王天娇, 严霞, 康钦威, 曲英晖, 刘宇飞. 7.8-7.4 ka天津海河南岸平原富硅藻层形成与相对海平面[J]. 中国地质.
    引用本文: 方晶, 王福, 商志文, 王天娇, 严霞, 康钦威, 曲英晖, 刘宇飞. 7.8-7.4 ka天津海河南岸平原富硅藻层形成与相对海平面[J]. 中国地质.
    FANG Jing, WANG Fu, SHANG Zhiwen, YAN Xia, LIU Yufei, WANG Tianjiao, KANG Qinwei, QU Yinghui. 7.8~7.4 ka environment of diatom-rich layer and relative sea level change in the south pain of the Haihe River, Tianjin[J]. GEOLOGY IN CHINA.
    Citation: FANG Jing, WANG Fu, SHANG Zhiwen, YAN Xia, LIU Yufei, WANG Tianjiao, KANG Qinwei, QU Yinghui. 7.8~7.4 ka environment of diatom-rich layer and relative sea level change in the south pain of the Haihe River, Tianjin[J]. GEOLOGY IN CHINA.

    7.8-7.4 ka天津海河南岸平原富硅藻层形成与相对海平面

    7.8~7.4 ka environment of diatom-rich layer and relative sea level change in the south pain of the Haihe River, Tianjin

    • 摘要:研究目的】为研究硅藻对全新世古海面以及最大海侵范围的指示意义,【研究方法】本文以渤海湾西岸沧州北部为研究区,通过取自第V道贝壳堤附近的3个30m深钻孔样品的硅藻分析和14C年代学研究,重建了富硅藻层的古环境和相对海面。【研究结果】结果显示,3个钻孔虽硅藻整体稀少,但各存在一层由泥炭及腐殖质灰色粘土组成的富硅藻层,厚10cm至60cm不等,由海向陆方向厚度变薄。其中,DC01孔,7473 cal BP由海水影响的沼泽环境转为陆相淡水沼泽环境,富硅藻层与下伏沼泽层指示当时的相对海面低于-6.37m; QX02孔,7513 cal BP由盐沼环境(I带)转为受海水影响的沼泽环境(II带)再转为受海水影响的盐沼环境(III带),I带和II带界限处指示相对海平面为-6.68m; QX01孔,7836 cal BP由淡水沼泽(I带)转为盐沼环境(II带),I带和II带界线指示相对海平面为-7.68m。【结论】海面在7.8-7.4 ka cal BP约350年的时间内上升了近1m,海水影响到第V道贝壳堤以西,盐沼和淡水沼泽环境是全新世海侵达到最大范围时岸线附近的主要环境类型,因此,在现代海面上升背景下,沼泽化是海岸地区面临的一个主要环境问题。

       

      Abstract: Objective In order to study the diatoms indication significance to the sea level and the maximum transgression range,Methods this paper analyzes the diatoms and AMS 14C dating data from three 30m deep drilling cores collected near Chenier V of northern Cangzhou, Bohai Bay.Results The results show that diatoms are rare in these drilling cores, and there is only one diatom rich layer in each core, which is composed of peat and humus gray clay. The thickness of the layer is 10 cm to 60 cm, and thinner from seaward to landward. 7473 cal BP, site of DC01 changed from a sea water influenced swamp environment to a fresh water swamp environment, indicating a relative sea level lower than -6.37m; 7513 cal BP, site of QX02 was transformed from saltmarsh environment (zone I) to sea water influenced shallow swamp, then to salt marsh environment (zone III), The elevation of the boundary between zone I and zone II indicating a relative sea level of -6.68m. 7836 cal BP, site of QX01 was transformed from a freshwater swamp (zone I) to a salt marsh environment (zone II). The boundary between zone I and zone II indicating a relative sea level of -7.68m.Conclusions Relative sea level raised~1m during these~350 years, and the sea water affected the area to the west of the Chenier V. The salt marshes and freshwater swamps were the main environmental types near the transgression maximum in the Early-Mid Holocene. Under the background of modern sea level rise, marshification is a major environmental problem that modern coastal areas must face.

       

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