湄洲岛海岸地貌特征及成因研究

湄洲岛海岸地貌的发育受海洋动力和断层活动双重控制。东部以海岸侵蚀为主,形成海蚀崖、海蚀平台、海蚀壕沟等地貌,在岬角间,形成海滩堆积;西部以堆积为主,形成淤泥质海滩,海蚀作用相对比东部弱。东峤断裂控制了台地和丘陵的分布,断裂东盘抬升形成丘陵,西盘下降形成台地。受北西—南东走向的仙游—郊尾断层左行运动影响,湄洲岛北部向西移动,南部向东移动,使岛的轮廓呈＂S＂形态。福建沿海在距今0.7—0.6万年前发生海侵时,湄洲岛处于断块抬升环境,就岛的局地范围,处于低海面;在0.4—0.3万年前福建沿海海侵达到高峰时,湄洲岛的海侵经历了两个阶段,第一阶段为水动型海侵,第二阶段为地动型海侵。

The Features and Genesis of Coast Landforms in Meizhou Island

The coastal landforms of Meizhou Island were mainly associated with the joint effect of both marine dynamics and fault activity.The east area of Meizhou Island was mainly controlled by costal erosion,and landforms such as marine cliff,abrasion platform and ditch were formed,but they were shaped into beaching in headland.The west area of Meizhou Island was mainly controlled by deposition,and silt beach was formed,but the effort of abrasion was weaker than the east.Distribution of platform and hilly land was controlled by Dong Qiao fracture,and hilly land was shaped by the uplift result of east wall while the platform was shaped by east wall decline.The cause of the north area of Meizhou Island westward movement and the south area eastward extrusion was influenced by left-slip of Xianyou-Jiaowei fault,and the result was that the outline of island presented ＂S＂ shape.Meizhou Island was being fault block uplift and the local scope of island was being sea level lowstand while marine transgression on the coast of Fujian about 7000—6000 years ago.Marine transgression on Meizhou Island came through two stages when the marine transgression on the coast of Fujing reached peak time in 4000—3000 years ago.The first stage was hydrodynamic marine transgression,and the second stage was seismic marine transgression.