5.10.2.5. Time

You would like to know the meaning of geomorphic processes. The endogenic and exogenic forces causing physical stresses and chemical actions on earth materials and bringing about changes in the configuration of the surface of the earth are known as geomorphic processes.

Geomorphic processes involve changes to the earth's surface due to two types of forces: endogenic (internal) and exogenic (external). Endogenic processes include tectonic activities that build up the land, while exogenic processes include weathering and erosion that wear it down. Both processes interact continuously to shape landscapes.

Think of a sandy beach. The waves (exogenic force) slowly erode the sand, while earthquakes (endogenic force) can create new beaches or reshape the coastline. This is a constant battle between building and wearing down, much like building a sandcastle at the shore only to see the waves wash it away.

As there are different climatic regions owing to variations in thermal gradients created by latitudinal, seasonal, and land and water spread on the surface of the earth, the exogenic geomorphic processes vary from region to region.

Climate significantly influences geomorphic processes. For example, in wet climates, abundant rainfall accelerates erosion as water transports sediment more effectively. In contrast, arid regions experience slower weathering since there is less moisture, affecting soil formation and surface features.

Imagine a forested valley versus a desert. The valley, with its rainy weather, sees trees grow and roots anchor the soil, preventing erosion. Meanwhile, the desert, with little rain, has little vegetation, leading to loose sand being blown away by the wind.

Erosion involves acquisition and transportation of rock debris...By erosion, relief degrades, i.e., the landscape is worn down.

Erosion is the process where rock and soil materials are worn away and then transported. Agents like water, wind, and ice actively participate in this process. As erosion happens, the surface features of the land decrease in height, leading to the formation of various landforms.

Think about a river carving a canyon over millions of years. The moving water (an erosional agent) continually chips away at the rocks and soil, deepening the canyon and altering the landscape much like how a sculptor shapes a statue from stone.

Weathering is defined as mechanical disintegration and chemical decomposition of rocks through the actions of various elements of weather and climate.

Weathering is crucial as it breaks down rocks into smaller particles, making it easier for erosion to occur. There are two main types: mechanical weathering, which physically breaks rocks apart, and chemical weathering, which alters the minerals within the rocks. Both types are essential for soil formation.

Consider how houseplants thrive in potting soil. The soil was once hard rock that weathered away into smaller pieces due to rain (chemical weathering) and freezing rain causing cracks (mechanical weathering), making it perfect for roots to grow.

Five basic factors control the formation of soils: (i) parent material; (ii) topography; (iii) climate; (iv) biological activity; (v) time.

Soil formation is influenced by various interconnected factors. The parent material provides the minerals, climate affects the degree of weathering, topography influences drainage and erosion, biological activity contributes organic matter, and time is necessary for these processes to mature the soil profile.

Think of a garden. The type of soil (parent material) affects what plants can grow there. Hills (topography) can create drier patches or pools of water. Climate will determine how quickly the plants grow and decompose, influencing the nutrients available for future plant life.

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