摘要
陆架大、中、小、巨沙丘(沙波)发育的动力机制与河流沙波有相似之处,也有许多差异,前者含定时多向的潮流、持续定向的洋流和偶发性的暴风浪流,后者为单向持续水流。20～100cm/s的底流速是发育沙丘的动力因素,水流的多向性和浪流的偶发性又常常制约沙丘发育的强度和迁移的速度;陆架浅水区(小于18m)受破浪的影响,沙丘尺度与水深呈微弱负相关,深水区水深的影响甚微。陆架输沙量是沙丘发育的物质条件,特别是细、中砂底质,在此粒度范围内沙波尺度与粒径呈微弱正相关,平缓广阔的地形在沙丘发育中也起一定的作用。
In the formation mechanism,sand dunes (waves) in the continental shelf are similar and also different from fluvial sand waves.The former is formed by multidirectional tidal currents,directional ocean current and occasional storm waves,while the latter is due to unidirectional water flows.The bottom current at 20～100 cm/s is the dynamic factor for the development of sand dunes,and the multidirectional currents and occasional wave flow often restrict the intensity of dune development and also the speed of migration.In the shallow area of the continental shelf (water depth is under 18 m),due to the influence from the breakers,the dune size is in weak negative correlation with the water depth,and in deep water area,the influence of water depth is very little.Sand transportation is the material condition for the dune development in the continental shelf,especially in fine and medium sand seafloor areas.Within such grain size areas,the dune size is in weak positive correlation with the grain size.Gentle and wide topographic feature also has a certain action on the development of sand dunes.
出处
《海洋地质动态》
2004年第4期5-10,共6页
Marine Geology Letters
基金
国家自然科学基金项目(40076013)
关键词
沙丘
动力机制
环境
陆架
sand dune
dynamic mechanism
environment
continental shelf
