Glacier

Glaciers, also known as glaciers, are ice bodies that are formed from snow and can move. In high latitude and alpine regions, when local snow permanently disappears, a certain thickness of snow can form ice through a series of physical changes. When the ice reaches a certain thickness, it can move under gravity and its own pressure, forming a glacier. In the peripheral areas of glaciation, due to the cold climate, large areas of land have been frozen for many years, forming permafrost and permafrost related landforms. Therefore, snow cover, glaciers, and frozen soil constitute the main driving forces for the formation and development of landforms in high latitude and alpine regions. There are two processes in which snow becomes ice, namely, new snow becomes granular snow, and granular snow then becomes glacial ice.

Areas above the snow line have accumulated snow over the years, and over time, the snow thickens. The polygonal snowflakes, due to changes in temperature and pressure during the day and night, melt and sublimate at the edges of the snowflakes during the day, and freeze again at night, forming a thin ice shell. When snow accumulates to a certain thickness, loose snowflakes gradually form granular ice, known as granular snow. The granular snow continues to thicken, generating greater static pressure, expelling air, and re forming dense, transparent, slightly blue glacial ice. Glacier ice is plastic, and under the action of pressure and gravity, it moves downward along mountain slopes or valleys, forming glaciers.

According to different shapes and scales, glaciers can be divided into the following types:

Mountain glacier: Also known as mountain glacier. This is a glacier developed on high mountains, mainly distributed in high mountain areas in mid and low latitudes. This glacier has a high snow line and a small area. According to their morphology and genesis, they can be divided into cirque glaciers, suspended glaciers, regenerated glaciers, and valley glaciers.

Continental glacier: refers to a glacier developed by infiltration and freezing during ice formation under continental climatic conditions. It is an ice flow that develops in polar regions, has the widest area, is extremely thick, and is not affected by underlying terrain. The glacier that rises from the edge to the center and forms a convex shape is called an ice shield. Larger, undulating continental ice flows are called ice sheets. The maximum thickness of the Antarctic ice sheet can reach 4276 meters, with an area of approximately 12.65 million square kilometers.

Plateau glacier: It is a transitional type between continental glacier and valley glacier. Due to its development on gently undulating highlands, it is called plateau glacier, also known as ice cap. Such as the Yosterdal Ice Cap in Scandinavia, which is 90 kilometers long and 10-20 kilometers wide. The flat top glaciers on the plateau in western China also belong to this type, but their scale is small.

Piedmont Glacier: It is formed in mountainous areas. Due to its large amount of ice, it reaches the piedmont through valleys and continues to flow outward. Some can extend to distant places and cover large areas of piedmont plains and depressions. It is as large as the Malasping Glacier on the Pacific coast of Alaska. It is formed by the convergence of 12 glaciers, covering an area of 2682 square kilometers. Due to changes in climatic conditions, such glaciers can either retreat and transform into valley glaciers, or expand into continental glaciers.