so that the fan comes into contact with topographic barriers, a confined fan is formed.

Wave or channel erosion of the edge of the fan (lateral erosion) sometimes produces a "toe-trimmed" fan, in which the edge of the fan is marked by a small escarpment. Toe-trimmed fans may record climate changes or tectonic processes, and the process of lateral erosion may enhance the aquifer or petroleum reservoir potential of the fan. Toe-trimmed