Basic concepts and significance of geomorphology
Geomorphology means a discourse on earth forms. The Geomorphological studies encompass landforms of the continents, their margins and the sea floor.
Landforms are studied from three different points of view:
‐The geologist looks into the geological controls in the evolution of landforms. In the study of landforms by geologists, understanding the historical and dynamic elements of the process that change the geological materials and structure is very important.
‐The geographer concerns with the adjustment of human activities in charging landforms.
‐The engineer assesses the terrain from the point of view of engineering construction and availability of materials for construction.
Sources and time of geomorphological activities:
All geological and geomorphological activities of the earth are due to endogenetic and exogenetic sources of energy. Example of endogenitic sources is the convection currents in the mantel that may produce earthquake, volcanoes and plate movements. Exogenetic sources may be represented by the solar radiation,
gravitational attraction and biological processes.
Landform units are studied not only with the reference to their magnitude, but also to the time it is taken to be formed. The time of the evoluti
Concepts of geomorphology
During the fifteens and sixteen evolution of landforms was based on the philosophy of catastrophism until James Hutton (1726 – 1797) has changed it to scientific though with his principle of uniformitarianism. This leads to the
‐First concept depends on the principle of uniformitarianism that conveys that the present is the key of the past. James Hutton applied this principle rigidly and stated that geological processes have been active at the same level of intensity throughout the geological time. IT IS NOW RECOGNISED THAT IT IS NOT TRUEthat the physical processes and laws which are in operation during the present time were active in the geological past, but notnecessarily with the same intensity as now.
‐Second concept: that in the evaluation of landforms, structure such as joint, folds, fault and permeability plays a crucial role and is reflected in the landforms. Geomorphic features developed on rocks are in general much younger to the structural features of the rocks.
‐Third concept is that geomorphic process operates not on a uniform rate but at differential rates resulting in the evolution of relief features. The processes are affected by many factors as altitude, temperature, moisture, type of vegetation and microclimatic condition.
‐Fourth concept that geomorphic processes produce distinctive imprints on landforms and characteristic assemblage of landforms evolve as a result to the operation of different geomorphic processes. For example, deltas and alluvial fans result by stream action where caves in limestone terrain are attributed to ground water
‐Fifth concept states that according to W. Davis (1850‐1934) thought that landforms display distinctive characteristic depending on the stage of their development. So that the evolution of landforms is through youth, maturity and old age stages. Though many geomorphologiste are not convinced of this
concept, because an orderly sequence of landforms come into being by the action of different erosional agents on the earth’s surface.
‐Sixth concept is that geomorphic evolution is one of complexity then simplicity. In one geomorphic process or cycle, remnants of landforms not related to the current cycle of erosion are recognized. Five categories of landforms including simple, compound, monocyclic, multicyclic and exhumed have been recognized.
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