论文部分内容阅读
采用探地雷达探测了昌黎海岸沙丘区典型横向沙脊和新月形沙丘的沉积构造,据此初步揭示了研究区海岸沙丘的沉积序列特征和发育过程。结果表明,昌黎海岸带在2 000aBP波浪作用下发育滨岸沙坝,沙坝主要以向海向陆缓倾斜的沉积构造为主,现今的风成沉积发育于滨海相沙坝之上。海岸带向海一侧经历了潮上带前丘到横向沙脊的过程,横向沙脊在东北风的作用下主要发育向陆倾斜的高角度交错层理,同时由于向岸合成风力的阶段性变化,这些层理的倾角略有差异,记录了海岸带风沙活动的周期性变化;内侧新月形沙丘由4组倾角不同的层理组成,被较大规模的二级界面分隔,复合新月形沙丘(链)经历了由盾状沙堆到典型新月形沙丘的加积发育并遭受风蚀的过程。
Using GPR to detect the sedimentary structures of the typical transverse sand dunes and crescent dunes in the Changli coast dune area, the sedimentary sequence characteristics and development of the coastal dunes in the study area are revealed. The results show that the Changli coastal zone develops sandbanks under the wave of 2000aBP. The sandbodies are dominated by sedimentary structures that gently dip toward the sea, and the present aeolian deposits are developed above the coastal sandbodies. The coastal zone experienced the process of tide-front cumulus to horizontal ridge on the seaward side. The horizontal sand ridge mainly develops high-angle cross-bedding stratification toward the land under the action of northeasterly wind. At the same time, Changes in the inclination of these strata slightly different record of cyclical changes in sandstorm activities on the coast; the medial crescent-shaped sand dune by the four groups of dip angle of bedding composed of large-scale secondary interface is separated, the composite crescent Shaped sand dunes (chains) underwent the process of accreting and sinking from shield-shaped sand piles to typical crescent shaped sand dunes.