Tag Archives: Ripple Marks

Geo-pic of the week: Ripple marks


Ripple marks are sedimentary features formed by water flowing over sediment.  They form in different environments including river channels, beaches, and just about anywhere water flows.  You probably saw some the last time you walked along a creek.

As water flows over sediment, it sweeps some of the loose sediment along in the direction of the current.  As the sediment migrates, it forms miniature dune-like structures.  These features are short on one side and tall on the other. The tall sides point in the direction the water was flowing.  In this case, it flowed into the picture, or away from us.

Ripples like these often get destroyed before they ever harden into a rock, but occasionally they get preserved.  Ancient ripples serve as clues to the environmental conditions that existed in a place in the distant past.  These ripples formed in what was once a deep ocean trough near Hot Springs, Arkansas .

GeoPic Of The Week: Ripple Marks In Sandstone

Ripple Marks In Sandstone

Ripple Marks In Sandstone

Ripple marks are sedimentary structures preserved in sandstone and limestone. They may be asymmetrical in shape, with the steep side pointing downstream in the direction of current flow.   In this picture the steep side is toward the viewer and so is the current direction.  Ripples form naturally by the movement of water currents in rivers and streams, on beaches of tidal and long-shore currents, and in deep-ocean basins.  This picture was taken of Ordovician age sandstone in the Everton Formation along Beaver Lake.