Classifications, sedimentary features and facies associations of tidal flats
Classifications, sedimentary features and facies associations of tidal flats
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滩涂分类、沉积特征及相组合
DOI：
10.3724/sp.j.1261.2013.00018
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发表时间：
2013-01-01
影响因子：
2.9
通讯作者：
Fan Daidu
中科院分区：
文献类型：
--
作者：
Fan Daidu
近二十年来，潮汐环境的研究取得了重大进展。这些研究突出了现代沿海环境中潮滩的重要性和多样性。根据潮滩的发育环境，将潮滩划分为9种类型，并根据潮滩受波浪作用的大小，将潮滩划分为遮蔽谱和裸露谱。对三元海岸分类模型进行了修订，增加了一个嵌入三角形，以突出非开阔海岸潮滩作为三角洲、河口和泻湖等一级海岸环境的主要二级形态要素。一个新的连续谱的开放海岸沉积设置提出了从潮汐优势与波浪影响的泥质潮滩，通过桑迪潮滩的混合能量（潮汐为主），和潮汐海滩的混合能量（波浪为主），以海滩的波浪优势与潮汐影响。值得注意的是，没有开放的海岸设置是绝对免受波浪或潮汐的影响。提出了潮坪沉积的三个诊断标准。在向上变细的层序中，（1）从扁平层理到波浪状层理再到透镜状层理的垂直变化是大多数潮滩的特征;（2）周期性潮汐韵律层指向典型的大潮汐河口内部的遮蔽潮滩;（3）风暴和潮汐沉积的韵律交替是暴露潮滩，特别是开阔海岸类型的特征。潮间坪沉积物的顶部通常是盐沼沉积物，但下面是不同的潮下带序列，如厚的潮下水道充填物、沙洲复合体（受保护的海岸环境）和向上变粗的潮下带坪序列或厚的潮下带沙脊/沙洲复合体（暴露的海岸环境）。
Significant progress has been achieved in the research of tide-dominated environments in the past two decades. These studies highlight both the importance and diversity of tidal flats in modern coastal environments. Based on their developing settings, tidal flats are subdivided into nine types, which are in turn grouped into sheltered or exposed spectrums according to the magnitude of exposure to waves. The ternary coastal classification model is revised with an embedded triangle to highlight non-open coast tidal flats as major secondorder morphological elements to the first-order coastal environments including deltas, estuaries and lagoons. A new continuous spectrum of open coast depositional settings is proposed from muddy tidal flats of tide dominance with wave influence, through sandy tidal flats of mixed energy (tide-dominated), and tidal beaches of mixed energy (wave-dominated), to beaches of wave-dominance with tide influence. It is worth noting that no open coast setting is absolutely exempt from wave or tide influence. Three diagnostic criteria for the intertidal-flat deposits are proposed. Upon an upward-fining succession, (1) regular changes vertically from flaser bedding, through wavy bedding and to lenticular bedding are diagnostic of most of intertidal flats; (2) cyclical tidal rhythmites point to sheltered intertidal flats typically at the inner part of macrotidal estuaries; (3) rhythmic alternations of storm and tidal deposition are diagnostic of exposed intertidal flats, especially the open coast types. Intertidal-flat deposits are generally topped by saltmarsh deposits, but underlain by different subtidal successions, like thick subtidal channelfills, sand-bar complexes (sheltered coastal settings), and upwards coarsening successions of subtidal flats or thick subtidal sand ridge/bar complexes (exposed coastal environments).