Abstract:

The formation and characteristics of fan delta on the steep slope are simulated by flume experiments. It is found that during the formation the fan delta prograde forward and accrete upward constantly. The frequent diverting and crevasse of channels on the fan surface are the dynamical mechanism in the development of fan delta. Because of the stop from waterbody in flume, the growth rate in lateral sides is quicker than that in the front of fan, the ratio of length and breadth of fan is less than 1. The change of water level in flume controls the characteristics of fan delta plain, and the descending of water level makes for the incision of channels and the progradation of the fan. The fan delta face is divided into three subfacies as plain, front slope and prodelta. These subfacies have different gradients on the fan surface and sedimentary dynamical mechanism, which result in the evident fan-surface gradient and granularity distributing.

Key words: fan delta, flume experiment, sedimentary simulation, fault basin, steep slope