The Natural Realms of the Earth -Lithosphere — Practice Quiz

V-shaped valley

Rivers flowing down steep mountain slopes have great cutting power and erode vertically into the rock, creating V-shaped valleys. These valleys are narrow at the bottom where the river flows and wider at the top. The swift flow of mountain rivers can move heavy rocks and cut deep into the mountainous terrain. This is different from U-shaped valleys which are formed by glaciers through a different erosional process.

The gradual breaking down of rocks by atmospheric forces

Weathering is the process by which rocks are gradually broken down by atmospheric forces like heat, cold, water, and moisture. During day and night, rocks expand when heated and contract when cooled. This repeated expansion and contraction makes rocks brittle and causes them to break down. Water also reacts with rock chemicals, further weakening them. This process prepares rocks for erosion and transportation by other agents like wind and water.

Delta

When a river reaches the sea, it slows down and deposits the fine sediments it has been carrying, forming a delta. The word delta comes from the Greek alphabet delta (Δ) because of its triangular shape. Examples include the Sundarbans delta formed by Ganga and Brahmaputra rivers, and the deltas formed by Krishna and Godavari rivers in Andhra Pradesh. Deltas are usually very fertile areas suitable for agriculture.

U-shaped valley

Glaciers create U-shaped valleys through processes of plucking and abrasion. Unlike rivers that cut narrow V-shaped valleys, glaciers are wide masses of ice that erode the entire valley floor and sides, creating a characteristic U-shape with a flat bottom and steep sides. The glacier acts like sandpaper, wearing away the bedrock as it slowly moves downhill. Examples can be found in the Himalayas and Alps where glaciers have carved these distinctive valleys.