Over time superficial cracks, joints, and folds of these layers were saturated with water. Ice formed in the fissures, melted under extreme desert heat, and winds cleaned out the loose particles. A series of free-standing fins remained.
As time passed, the surface layers developed cracks, joints, and folds that were filled with water.  Ice formed within these fissures, then melted due to extreme desert temperatures. Wind swept away any loose debris, leaving behind a series of free-standing fins.