Discuss the problems of erosional surfaces and explain the different methods to identify them with suitable diagrams.
Erosion is the geological process in which earthen materials are worn away and transported by natural forces such as wind or water. A similar process, weathering, breaks down or dissolves the rock, but does not involve movement. Geographers such as William Davis, Walther Penck, etc. gave the concept of erosional surfaces.
Physical erosion describes the process of rocks changing their physical properties without changing their basic chemical composition. Physical erosion often causes rocks to get smaller or smoother. Rocks eroded through physical erosion often form clastic sediments.
Problems of Erosional Surfaces
- Identification of erosional surfaces is difficult because each geographer gave different types of different landforms at the end of the cycle. For example, Davis gave Peneplain, and Walther Penck gave Endrumpf.
- The variety of complexity of landforms and rejuvenation has created a different types of erosional landforms. For example, the Chotanagpur plateau faces three major upliftment due to Himalayan orogeny and hence have rejuvenated landforms.
- Exhumes surfaces that are not erosional surfaces but got misinterpreted.
- How to gather the evidence of erosional landforms as a long time period has evolved.
- Researchers’ deductive power is very subjective since each has interpreted their own theories differently.
Different Methods to Identify Erosional Surfaces
Direct Methods:
- Gathering evidence based on landform evidence, drainage evidence, and sedimentary evidence.
- Dating Technology: The dating of geomorphic surfaces is critical to understanding landscape evolution. Example: Radiocarbon dating, is widely applied on organic matter preserved either within an aggradation fill or in the veneer of gravels that commonly mantle strath terraces.
Indirect Methods or Remote Sensing Methods: The erosion features map is one of the basic maps in erosion and sediment studies and watershed management programs. Examples using RS and GIS were compared in recent research which took place in the Jajrood sub-basin in northeast Tehran, Iran. In geomorphology study of various types of erosional landforms is an essential part of the study. From time to time new methods are adopted for studying these erosional landforms. The advance in technology help to better analyzes the landform’s evolution and erosions.