Rifts in Spreading Wax Layers

Abstract

We report results on the rift formation between two freezing wax plates floating on molten wax which are pulled apart with constant velocity. Several distinct patterns were observed for increasing spreading rates; a stable straight rift, a spiky rift with fracture zones almost parallel to the spreading direction, and a regular zigzag pattern characterized by an angle dependent on the spreading rate. The characteristic angles of the zigzag pattern agree with a simple geometrical model. The coarsening of the pattern over time and the three-dimensional structure of the crust are also discussed.