Rhythmic Linear Sand Bodies Caused by Tidal Currents

摘要: A study was made of bathymetric charts those coast lines characterized by large vertical tidal ranges (greater than 10 feet). In these areas currents are strong (1-5 knots) and may significantly affect sedimentation. Two characteristic types sand accumulation were found which appear to be formed currents. Both exhibit wave-like profiles, a scale significant oil exploration. The first type is here called "tidal current ridges." These rhythmic series ridges oriented parallel with They 25-100 feet high, 5-40 miles long, spaced 1-6 apart. Most composed sand, but some mud or silt. Their spacing proportional the depth water. origin appears related similar problem hydraulic geometry stream channels. Although best developed in Bay Korea Gulf Cambay, present wherever velocities range between 1 5 knots supply sediment available. second waves. ripple marks perpendicular direction. Recent evidence European oceanographers has indicated that, whereas rivers waves fairly small-scale features, open ocean they commonly have heights exceeding 25 feet. Cartwright Stride shown wide distribution this size, particularly North Sea. relation not known, although occur same environment. Since now shallow areas, their effect should visible percentage shallow-water deposits geologic past. particular it suggested that lenticular sands Chester Series Illinois, Cardium Formation Canada, Clinton Ohio show effects. pattern considered other shoestring sands.