Active tectonic and models of landscape development

 Many geologists concern about land formation. William Morris David has great contribution on development of this concept. He revealed his famous geomorphological model. It described that land formations has a ‘cycle of erosion’ which elaborated through “youth” to “maturity” to “old age”. His model contents tectonic force as an impulsive event that occurs earlier in geomorphic cycle. Land formation process occurs earlier in cycle. Subsequently geomorphic process constitutes effect and deformation and finally it form as a peneplain.

Opposed model has elaborated by Walther Penck in 1950’s against the W.M. Davis geomorphic cycle. Penck suggested wave pattern tectonic forces occur at the beginning of the cycle or ahead of plate tectonic deformation. In this scheme deformation increase step by step towards its ultimate stage and after weaken. His model invoked rock uplifted and land formation until ultimate stage. Geomorphic process uplifted the region through orogeny forces. There for land scape are resulted from the combined action of deformation and erosion.

 

John Hack elaborated third model of land formation. If Land forms exist for long intervals from erosion and deformation it will reach dynamic equilibrium. He discovered that land forms are not increase unbounded even though forces are prolonged for long time and produced final force to rock. Supplementary slope fractures limited the land scape elevation while parent rock continually uplifted. This condition exists until land formation reach dynamic equilibrium. In this model orogeny forces and erosion are become prolong equilibrium.

Here deformation rates are not obstructed like other models. If land form reaches its final stage then it not needs supplementary growing. Fluctuations are occurs around the land form until tectonic forces become constant.