论文部分内容阅读
南通地区位于长江三角洲北翼,其冰后期的环境变化以最大海侵时期为界,之前为海侵期,表现为海水入侵,陆地面积减少。之后海面趋于稳定,长江泥沙在河口地区持续沉积的作用下,表现为南通地区的逐渐成陆过程。利用收集的84个分布于南通地区及附近的钻孔剖面资料,将其按不同厚度的沉积相进行整理,结合前人研究成果,根据不同的数据基础运用IDW(Inverse Distance Weighted)插值对南通地区冰后期沉积厚度分布和环境变化过程分别进行了初步研究。结果表明:南通地区古河谷区是冰后期主要的泥沙沉积区,沉积物厚度、体积和重量大于北翼地区,北翼前缘沉积要大于后缘。冰后期古河谷区沉积泥沙4 892.2×108 t,北翼地区沉积泥沙1 045.3×108 t,二者之比约为4.7∶1.0,泥沙沉积强度之比约2∶1。从冰后期海侵初期到最大海侵时期,再到南通成陆的晚期,南通地区水域面积比例先由62.2%上升到95%,再缩减到33.1%,陆地面积比例先由37.8%缩减到5%,而后又上升至66.9%。尽管钻孔资料可以为南通地区有历史记载之前的时期提供宏观的环境变化框架,但由于钻孔资料在测年数据及沉积相的划分方面分辨率较低,在表现南通地区历史时期的环境变化方面存在不足,需要结合考古、文物等历史资料和土壤分布等自然地理信息进行更为详细的研究。
The Nantong area is located in the northern wing of the Yangtze River Delta. The late-glacial environmental change was bounded by the period of maximum transgression and earlier transgression, which represented the invasion of seawater and the reduction of land area. After the sea surface stabilized, the Yangtze River sediment sustained deposition in the mouth area, the performance of the Nantong area gradually into the land process. Based on the collected data of 84 borehole profiles distributed in and near Nantong area, the sedimentary facies of different thicknesses are sorted out. Based on the previous research results and IDW (Inverse Distance Weighted) interpolation, the Nantong area The post-ice sediment thickness distribution and the process of environmental changes were preliminarily studied. The results show that the ancient valley area in Nantong is the main sediment deposition area in the late ice period. The thickness, volume and weight of the sediments are larger than those in the north wing area, and the leading edge of the north wing is larger than the trailing edge. The depositional sediment in Furukawa region during the late ice period was 4 892.2 × 108 t, while that in the north wing region was 1 045.3 × 108 t. The ratio of the two was about 4.7:1.0, and the ratio of sediment deposition intensity was about 2: 1. From the early stage of transgression to the maximum transgression of the late ice period and then to the late stage of Nantong formation, the area ratio of Nantong waters first increased from 62.2% to 95% and then to 33.1% again, and the proportion of land area decreased from 37.8% to 5 %, Then rose again to 66.9%. Although borehole data can provide a macroeconomic framework for environmental changes in the Nantong area before the historical records, the drilling data show low resolution in dating data and sedimentary facies. Therefore, environmental changes in the history of the Nantong area There are some shortcomings, such as archeology, cultural relics and other historical data and the distribution of soil and other natural geography information to conduct a more detailed study.