A glacier is a natural body of ice that persists over long periods in polar or alpine regions and moves gradually along the ground.

Over many years, glaciers accumulate layers of snow that transform through compaction, recrystallization, and refreezing processes.

With distinct shape, structure, and plasticity, glaciers undergo plastic flow and block sliding due to gravity and pressure, making them vital freshwater resources on Earth.

Glaciers are morphologically classified into two primary types: continental glaciers and mountain glaciers. Continental glaciers, or “ice sheets,” are vast bodies of ice covering large land areas, such as entire islands or continents. Mountain glaciers, also known as “alpine glaciers,” form in mountainous regions and are heavily influenced by surrounding terrain. Based on their shape, mountain glaciers can be further classified into types such as hanging glaciers, ice bucket glaciers, valley glaciers, and foothill glaciers.

Glaciers shape the Earth’s surface, creating unique glacial landforms categorized as climatic landforms. Today, about 11% of Earth’s land surface—primarily in polar regions, mountains, and plateaus at middle and low latitudes—is covered by modern glaciers. During the Quaternary ice age, extensive continental ice caps spread across Asia and North America, surpassing current glacier boundaries and leaving numerous glacial traces on the landscape.

Glacial Erosion:

Glacial erosion occurs through two primary processes: pull erosion and abrasion.

Pull Erosion:

In pull erosion, the glacier pulls up rock from the underlying bedrock or the ice bucket bed. The glacier freezes onto loose bedrock, which is then carried away as the glacier moves, lifting rocks along with it.

Abrasion:

Abrasion occurs as the glacier slides, with debris embedded in the ice grinding against the bedrock, continually etching and shaping it.

The Glacier's Role in Carrying:

Glacial erosion generates a substantial amount of loose debris, including rocks from collapsed mountain slopes. These rocks become part of the glacier and are transported downstream. The rock debris carried by the glacier is known as moraine.

The Accumulation of Glaciers:

After glacial ablation, various materials carried by the glacier accumulate to form glacial deposits. This glacial debris is typically poorly sorted, with mixed sizes and low roundness of gravel due to grinding.

Glacial landforms include ice erosion landforms, moraine landforms, and landforms created by ice and water accumulation.

Ice Erosion Landforms:

Ice Bucket:

Found at the glacier’s source, an ice bucket is a chair-like depression surrounded by steep rock walls. Its bottom is a smooth, rock basin that often slopes downhill toward an opening, which can become an ice bucket lake as water fills the depression after the glacier recedes.

Edge Ridge:

This blade-shaped ridge forms between adjacent ice buckets, creating a narrow, sharp divide.

Angle Peak:

Angle peaks are formed at the intersection of the back walls of multiple ice buckets, resulting in a sharp peak rising at the top.

Glacial Valleys:

Also known as "U-shaped" valleys or troughs, these valleys are carved by glacial erosion and widened over time. The thickness of glacial ice affects the intensity of erosion, contributing to the valley's distinct shape.

Sheep Back Stone:

A glacial erosion feature on the glacier bed, composed of bedrock hills that resemble a group of sheep from a distance.

Glaciers, as dynamic forces that shape Earth’s surface, play a crucial role in freshwater resources and create diverse glacial landforms through erosion and movement. Gaining insight into these processes enhances our understanding of the Earth’s evolving landscape shaped by these powerful icy formations.