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

基于地层沉积结构的古水文条件估算实验研究。

基本信息

批准号：
03452069
负责人：
MASUDA Fujio
金额：
$ 2.69万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-03452069/
关键词：
flume experiments ripples combined-flow pako-hydroulic condition sedimentary structures ベッドフォ-ム

项目摘要

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.

对合并流动波纹进行的通用实验进行了详细的纹波标准。使用了带有波发生器的循环水槽，其中单向流的方向是可逆的。基于涟漪圆度，确认了两种类型的波纹，以波浪为主和电流为主的合并流动波纹。当单向速度超过约19 cm/sec时，电流为主的波纹出现。组合流纹波的指示性特征如下：（1）圆形的李和侧面，圆形的槽在电流主导的波纹中也很明显。随着振荡性速度相对大小与非向速度的相对幅度变得较低，圆度变得更强。较大的单向速度通常会导致较高的不对称性。（2）内部结构的特征是凸的前凸层，脚趾和截断的槽的极度sigmoidal形状，用于电流为主的纹波。其中一些被识别出波浪主导的波纹，其外部形式非常接近波浪波纹。（3）合并流动纹波的谷物织物的特征是，首选的刺激模式在单个森林层层中都从一部分到一部分出现。独特的圆形轮廓是由沙粒在迁移波纹中的特征运动产生的。最重要的现象是仅在涟漪侧旁边产生的涡流，这是由于振荡和单向组件的共存而引起的。将实验结果应用于地质记录，以证明这些标准可用于与波浪和流阵相结合的波动区分的标准。当前的涟漪，以及雪橇过程和沉积环境的估计。