What are bowl-shaped depressions or hollows found near mountain peaks called?
Bowl-shaped depressions or hollows found near mountain peaks are often referred to as cirques. A cirque is a glacial landform that typically forms due to the erosive action of glaciers over long periods of time. Glaciers are large bodies of ice that move downhill under the force of gravity.
Formation of Cirques
Bowl-shaped depressions or hollows found near mountain peaks, known as cirques, are formed through the process of glaciation. Glaciers are powerful agents of erosion that gradually shape the landscape over thousands of years. In the formation of a cirque, glaciers erode the landscape through processes such as plucking and abrasion.
Plucking and Abrasion
Plucking refers to the picking up and removal of rocks and debris by the glacier as it moves. When a glacier moves downhill, it plucks rocks and debris from the bedrock, carrying them along and further eroding the landscape. Abrasion occurs when the glacier's ice and sediments grind against the bedrock, wearing it down over time.
Cirque Features
As the glacier moves downslope, it carves and scoops out the landscape, creating a deep, amphitheater-like hollow with steep walls. This bowl-shaped depression is what is known as a cirque. Cirques are typically found in high-altitude regions, near mountain peaks or along the sides of valleys.
Significance of Cirques
Cirques often contain small lakes, called tarns, which form when the cirque hollow fills with water from snowmelt or precipitation. These glacial features can be visually striking, with steep walls and often a concave shape that opens toward the direction from which the glacier originated.
Cirques are important in the formation of other glacial landforms, such as arêtes (sharp ridges between cirques) and horns (pyramidal peaks formed by the erosion of cirques on multiple sides). They are also significant in the study of glacial and geological history, providing evidence of past glaciation and the shaping of mountain landscapes by ice.