Evolution of sandstone mesas – following landform decay until death.

Mesas are residual landforms typical for layered rock sequences, formed due to tableland dissection and cliff retreat. Caprock cliffs are characteristic elements of mesa morphology. Mesas have finite lifetimes and over time are reduced in area, transforming into buttes and eventually into irregular arrays of boulders. Thus, they are ‘born’, when separated from a plateau, and ‘die’, when the caprock completely disintegrates. In this paper, sequential development of sandstone-capped mesas is first inferred from theory and then verified on the basis of field observations and landform inventories from a sandstone tableland of the Elbe Sandstone Mountains in the eastern part of Germany. Finally, selected morphometric parameters of mesa morphology, potentially indicative of their evolutionary phases, are computed from a high-resolution digital terrain model. Both field evidence and results of morphometric analysis indicate that mesas evolve along various pathways and, tending towards specific end-members, illustrate the principle of equifinality. Space-for-time substitution, if applied with care, may also be helpful in deciphering the geomorphic history of mesas and tracing their life until disappearance. [ABSTRACT FROM AUTHOR]