Crevasse splay

 ( Rivers ) 

A crevasse splay is a sedimentary fluvial deposit that forms when a stream breaks its natural or artificial levees and deposits sediment on a floodplain. A breach that forms a crevasse splay deposits sediments in similar pattern to an alluvial fan. Once the levee has been breached the water flows out of its channel. As the water spreads onto the flood plain sediments will start to fall out of suspension as the water loses energy. The resulting deposition can create graded bedding similar to those found in . In some cases crevasse splays can cause a river to abandon its old river channel, a process known as avulsion.Boggs, S. Jr., 2012, Principles of Sedimentation and Stratigraphy: New Jersey, Prentice Hall, 218 p. Breaches that form a crevasse splay deposits occur most commonly on the outside banks of where the water has the highest energy. Crevasse splay deposits can range in size. Larger deposits can be thick at the levee and spread wide, while smaller deposits may only be thick.Mjøs, R., Walderhaug, O. and Prestholm, E. (2009) Crevasse Splay Sandstone Geometries in the Middle Jurassic Ravenscar Group of Yorkshire, UK, in Alluvial Sedimentation (eds M. Marzo and C. Puigdefábregas), Blackwell Publishing Ltd., Oxford, UK.