论文部分内容阅读
通过对沧州CZ01孔岩芯野外描述,采样以及室内粒度分析和光释光(OSL)年代测定,探讨了沧州地区晚更新世以来的环境演变过程。结果表明,该岩芯垂直剖面沉积物颗粒基本构成是以黏土、粉砂、砂为主,沉积环境变化频繁。根据岩性特征及粒度参数特征可以划分为3大阶段:深度201.2～159.6 m为阶段Ⅰ,年代对应于200～128 ka B.P.,为中更新世晚期河流相与河湖交替沉积环境,下部以灰色-灰黄色粉细砂、细砂及中细砂为主,为河流相沉积,上部主要为棕黄色、灰黄色黏土、粉砂质黏土,为河湖相沉积;深度159.5～26.6 m为阶段Ⅱ,年代对应于128～12 ka B.P.,为晚更新世两个完整的沉积旋回,沉积物粒度经历了由粗-细-粗-细的变化过程。其中,第一旋回上部为灰黄色、浅黄色粉砂质黏土与黏土质粉砂,中夹灰色或灰黑色海侵相沉积的黏土质粉砂或粉砂质黏土,下部为灰色灰黄色粉细砂、中细砂,含小砾石。第二旋回上部以灰色-灰黄色黏土、黏土质粉砂为主,下部为浅灰色、灰黄色粉细砂、细砂、中砂;深度26.6～0 m为阶段Ⅲ,对应于全新世以来(12 ka B.P.以来)河湖相沉积,主要以灰色、灰黑色、灰黄色、黄灰色黏土质粉砂、黏土为主,中间分布海相层或海陆过渡相(潮滩相)的灰色、灰黑色或黑色黏土质粉砂或粉砂质黏土。
Based on the field description, sampling, indoor particle size analysis and OSL dating of core CZ01 in Cangzhou, the evolution of environment in Cangzhou since the late Pleistocene was discussed. The results show that the sediment particles in the vertical section of the core are basically composed of clay, silt and sand, and the sedimentary environment changes frequently. According to the characteristics of lithology and characteristics of grain size, it can be divided into three stages: the depth from 201.2 to 159.6 m is Stage I, the age corresponds to 200 to 128 ka BP, which is the sedimentary environment of river facies and rivers and lakes alternate in the late Middle Pleistocene, - The grayish-yellow fine sand, fine sand and medium fine sand are mainly river sediments. The upper part is mainly of yellow-brown, gray-yellow clay and silty clay, which are sediments of rivers and lakes. The depth of 159.5-26.6 m is Phase II The ages correspond to 128-12 ka BP, two complete sedimentary cycles of Late Pleistocene. The grain size of the sediments underwent a coarse-thin-coarse-thin variation. Among them, the upper part of the first cycle is grayish yellow, light yellow silty clay and clayey silt, clayey silty sand or silty clay deposited in gray or gray-black transgressive phase, the lower part is grayish grayish yellow fine powder Sand, fine sand, with small gravel. The upper part of the second cycle is mainly composed of gray-grayish-yellow clay and clayey silt, while the lower part is light gray, yellowish-yellow fine sand, fine sand and medium sand. The depth from 26.6 to 0 m is Stage III, corresponding to the Holocene 12 ka BP) lacustrine facies, mainly gray, gray-black, gray-yellow, yellow-gray clay silt, clay, the middle distribution of marine phase or transitional phase (tidal flat phase) of the gray, gray and black Or black clay or silty clay.