深水牵引流形成的床形单元组合

BEDFORM UNIT ASSEMBLAGES OF DEEP-WATER TRACTION-CURRENT ORIGIN

海底上发育深水牵引流形成的各种床形单元 ,包括等深岩丘及大型沉积物波在内的不同床形单元有规律地组合在一起 ,对于此类床形组合的确切形成机理 ,目前仍在探讨之中。本文经详细研究得出以下几点进展 :①运用内波理论可对海底上大型沉积物波各组成单元的成因作出较为合理的解释 ,向深海方向传播的内波可形成向上坡方向迁移的大型沉积物波 ;②在等深流与上覆低密度水体之间的界面上具备产生大规模界面内波的条件 ;③某些底流成因的床形单元组合属于等深流与等深流所引发内波的联合作用的产物 ,首次提出了等深流 -内波沉积组合的概念 ;④在现代海底上及古代地层记录中均发现了等深流 -内波沉积组合的实例 ;

Modern investigations of sea floor illustrate that various bed forms of bottom currents origin are well developed on sea floor. Different bed forms including contour drifts and sediment waves associate with each other orderly. The exact formation mechanism of these associations, especially to the sediment waves of up slope migration, is not fully understood by predecessors. Through detailed study of these bedform associations, this article reached several conclusions as follows: ① according to the theory of internal waves, the formation of different units which make up the sediment waves can be explained. The internal waves of seaward propagation can create sediment waves migrating up slope. ② The contour currents colliding with the overlapped low density normal seawater can create internal waves of large scale at the interface of the thermohaline. ③ Using the co effect of contour currents and internal waves, this article interprets the formation mechanism of those bedform associations developed on seafloor. ④ The examples of deposits associations of contour current internal wave co effect origin are developed in the stratigraphic record as well as on modern sea floor. Based on these conclusions, this article proposed the concept contour current internal wave deposits associations for the first time. A synthetic model of deepwater traction deposits in the statigraphic record is also proposed.