Exoperimental study of estimation for paleohydraulic conditions based on sedimentary structures in strata.

对混合流波纹进行了一般性的实验，以提供详细的波纹判据。采用了一种带造波装置的环流水槽，其单向水流方向是可逆的。根据涟漪圆度的大小，识别出波控型和流控型两种混合流波纹。当单向速度超过约19 cm/sec时，出现电流主导的波纹。混合流波痕的特征表现为：（1）在主流波痕中，背风面和背风面均为圆形，波谷也为圆形。随着振荡速度与无向速度的相对大小的减小，圆度增大。较大的单向流速往往导致更高的不对称性;（2）内部结构的特点是凸向上的前积层，脚趾和截断槽的极端S形，为电流为主的波纹。其中一些被认为是在波为主的波纹，其外部形式非常接近的波波纹;和（3）的字符组合流波纹的纹理结构是，首选的叠瓦模式波和电流波纹出现在一个单一的森林叶片的一部分到另一部分。这种独特的圆形剖面是沙粒在迁移沙纹上运动的特征。最重要的现象是在波痕的背风侧产生了由振荡分量和单向分量共同作用而产生的旋涡，并将实验结果应用于地质记录，证明了这些判据可用于区分复合流波痕与波流波痕，以及估计沉积过程和沉积环境。

Generic experiments on combined-flow ripples were carried out to provide detailed criteria of ripples. A recirclating flume with a wave generator was used, in which the direction of unidirectional flows was reversible. Two types of ripples, wave-dominated and current-dominated combined-flow ripples, were recognized based on the ripple roundness. The current-dominated ripples appeared when the unidirectional velocity exceeded approximately 19 cm/sec. The indicative features of combined-flow ripples were revealed as follows : (1) rounded lee and stoss sides, and also rounded troughs were remarkable within the current-dominated ripples. The roundness became stronger as relative magnitude of oscillatory velocity to undirectional velocity became lower. A larger unidirectional velocity often resulted in a higher asymmetry ; (2)the internal structures were characterized by convex-upward foreset laminae, the extremely sigmoidal shape of toes and truncated troughs, for current-dominated ripples. Some of these were recognized in wave-dominated ripples, whose outer forms were very close to that of wave ripples ; and (3) the character of the grain fabric of combined-flow ripples was that preferred imbrication pattern both of the wave- and current-ripples appeared from part to part in a single forest lamina. The unique round profiles resulted from the characteristic movement of sand particles on migrating ripples. The most important phenomenon was vortices generated only beside lee sides of the ripples, caused by the coexistence of the oscillatory and unidirectional components.The experimental results were applied to geologic records to prove those criteria available for the distinction of combined-flow ripples from wave and current ripples, and the estimation of sedimetary processes and depositional environments.