浙江省沿海砾石滩地形地貌特征与发育模式

Topographic and geomorphological characteristics and development pattern of gravel beaches along the coast of Zhejiang Province

  • 摘要: 利用2019年7月和2020年7—8月的浙江省海滩现场调查数据,结合历史数据资料,系统分析了浙江省不同区域砾石滩的剖面地形特征、平面形态特征和表层沉积物粒度特征; 同时, 利用相关性分析、主成分分析、聚类分析和非度量多维尺度分析等数理统计方法,探讨了影响浙江砾石滩发育的主要因子,阐明了浙江砾石滩的发育模式。结果表明:① 从剖面形态可以看出,浙江砾石滩剖面形态大多呈斜线型,部分砾石滩呈肩滩型。从平面形态可以看出,浙中海域砾石滩海滩规模较大,岬角遮蔽能力较弱,因此受到的波浪作用最强。从沉积物粒度分布特征可以看出,浙中海域雀儿岙岛以北的砾石滩沉积物较粗,而浙中海域和浙南海域砾石滩则具有较多的扁长和杆状砾石。② 浙江砾石滩可分为3个类群:第一类群主要分布在浙中浙南海域,受潮流作用较强;第二类群主要分布在浙北海域,受潮汐作用较弱,规模较小,而第三类群分布较为分散,规模较大。③ 地质构造背景、水动力环境以及沉积物来源等对浙江砾石滩的形成过程具有重要的影响,其中地质构造背景是海滩发育的主要影响因素。砾石滩在进行生态保护和生态恢复过程中,还需要考虑波浪作用和潮汐作用的影响。

     

    Abstract: Using on-site survey data from July 2019 and July-August 2020 in Zhejiang Province, combined with historical data, we systematically analyzed the characteristics of topological profiles, planar morphology, and surface sediment grain size of gravel beaches in various locations of Zhejiang Province. Meanwhile, using mathematical statistical methods such as correlation analysis, principal component analysis, cluster analysis, and non-metric multidimensional scaling,, the main factors affecting the development of the gravel beaches were explored, and the development pattern of the gravel beaches was elucidated. Results indicate that in the profile morphology, it can be seen that most of the gravel beach profiles are oblique line typed, and some of them have a beach berm. In planform, gravel beaches in the central Zhejiang sea area are relatively larger, have weaker headland, and thus the shielding ability is weak and undergo stronger wave action. In distribution pattern of sediment particle size, the gravel beaches north of Que'er Ao Island in the central Zhejiang sea area have coarsest pebbles and thicker deposits, while those in the central and southern Zhejiang sea areas have more prolate and club-shaped gravels. The gravel beaches in Zhejiang could be placed into three groups by cluster analysis. The first group is mainly seen in the central and southern Zhejiang, and is strongly affected by tidal currents. The second group is mainly distributed in the northern Zhejiang, with weaker tidal effects and smaller. The third group distributed more sporadically in the province and relatively coarser. The geological structure background, hydrodynamic environment, and sediment supply have important impacts on the formation process of the gravel beaches, among which the geological structure background is the main factor on beach development. For the ecological protection and ecological restoration regarding the gravel beaches, the influences of wave action and tidal action must be considered.

     

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