i. MountainsÂ
Mountains are formed through various processes as explained by plate tectonics depending upon which these are classified as Fold, Volcanic, or Block mountains.
Although these appear as giant static units, when studied on the geological time scale, it is observed that these are continuously under dynamic changes. For eg: the Aravallis of India formed during Precambrian times, denuded and lowered in height over time, now stands as a relic of ancient fold mountains.
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Changes In Mountains And Their Reasons
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- Gradual denudation and lowering of reliefs due to geomorphic processes such as weathering and erosion by rivers, wind, groundwater, etc
- Endogenetic forces such as volcanism lead to the development of new volcanic mountains or changes in old formations.
- Anthropogenic causes such as urbanization, tourism, agriculture, and other developmental activities affect the morphology of mountains.
- Natural disasters such as earthquakes and landslides bring major structural and morphological changes in mountainous regions.
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Effects Of These Changes
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Positive
- Weathering and erosion help in soil formation downslope For eg: Great Indian Plains
- Helps in understanding the formation and development of reliefs and their compositions
- Mining helps in the extraction of various mineral resources.
- Better planning and management practices. For eg: The watershed development program
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Negative
- Loss of surface soil from slopes devoid of mountains of fertile soils
- Lack of knowledge of slope management practices renders developmental activities vulnerable to exceeded weathering and erosion as well as natural hazards
- Natural disasters such as earthquakes and landslides cause damage to human life and property. For eg: the Himalayan region is under Zone 4 and Zone 5 of Earthquake mapping zones in India
- Threat to water security as mountains provide nearly 70% of freshwater to the planet
- Threat to livelihood as mountains provide nearly 20% of global tourism.
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