摘要
深水沉积物波是在海底发育普遍、规模较大的一种波状沉积体 ,大多数学者将它们解释为等深流沉积或浊流沉积。作者结合内波理论的研究进展 ,考虑内波沉积作用的水动力学特征 ,探讨了深水沉积物波的内波成因机制 ,得出以下几点认识 :①海底流动单独作用无法满足沉积物波形成所需的流动层厚度及流动速度 ,较难解释沉积物波的迁移方向及规则的内部及外部形态。②内波可以引起海底流动 ,内波比表面波更容易形成更大规模的沉积床形。③内波可以形成大型沉积物波 ,用内波可以较合理地解释内波的对称波形单元、非对称波形单元及上攀波形单元的成因。波动面离海底距离较大的行进内波及内驻波可以形成对称波形的沉积物波 ,波动面离海底较近的行进内波及内孤立波可以形成非对称波形的沉积物波 ,内波引起的海底流动进一步增强时 ,可形成上攀波形沉积物波。④行进内波可以形成向内波传播相反方向迁移的沉积物波 ,向海盆内部传播的内波可以形成向上坡方向迁移的沉积物波。
Deep water sediment waves are the wavy depositional bodies with a large scale and well developed on the seafloor. They have been universally interpreted as contour current or turbidity current deposits. On the basis of a new development of the theory of internal waves, the generation mechanism of the deep water sediment waves by the action of internal waves are studied in consideration of the hydrodynamics of internal wave deposition. Several conclutions are as follows: 1)Alone action can not interpret the origin of the sediment waves and can not meet the requirement of velocity and thickness for generating large sediment waves. 2) The internal waves can induce bottom currents and form a larger scale of depositional bedforms than surface waves. 3) The internal waves can build the sediment waves of large scale. The origin of sinusoidal, asymmetric and climbing wavy units of the sediment waves can be reasonably interpreted by the internal waves alone. The sediment waves with a sinusoidal wavy shape can be formed either by the progressive internal waves propagating along the wave interface relatively high above the seafloor or by the standing internal waves. The sediment waves with a asymmetric wavy shape can be formed either by the progressive internal waves propagating along the interfaces near the seafloor or internal solitary waves. When the internal wave for inducing the bottom currents increases further, the sediment waves with a climbing wavy shape should be formed. 4) The progressive internal waves can build the large sediment waves migrating in the opposite direction of the propagating direction of the internal waves. The progressive internal waves propagating toward the deep sea basins can build the large sediment waves with the up slope migrating direction. This is the reason why the sediment waves well developed on the seafloor migrate mainly up slope.
出处
《古地理学报》
CAS
CSCD
2002年第1期83-89,共7页
Journal of Palaeogeography：Chinese Edition
基金
国家自然科学基金资助项目 (4 9872 0 5 0 )
关键词
深水沉积物波
内波沉积
内波
等深流
浊流
deep water sediment waves, internal wave deposits, internal waves, contour current, turbidity current
