One of the most powerful, albeit slow moving forces of nature are glaciers. A single glacier can carve out vast canyons in the side of a mountain and move millions of tons of rock and debris.
Glacier ice is anywhere from the size of a bus to hundreds of kilometers long and several kilometers wide. Glaciers form when more snow accumulates in an area each year than melts and runs off. The weight of this snow compresses the underlying layers into solid ice, which over time forms glacial ice, or glacier ice.
This ice is more dense than the surrounding snow, so it will gradually move under its own weight.
There are two types of glaciers: valley or alpine glaciers and continental glaciers. Valley glaciers originate in mountain valleys and flow downhill from there. Continental glaciers originate from a region of snow accumulation called a “Cirque” that extends far beyond the valley floor and creates a huge dome of ice.
Alpine glaciers: – Come from mountain valleys (can be as small as one meter high) – Begin with snowfall on top of existing glacier, which is compressed to form ice.
Continental glaciers: – Originate in a dome of snow called a “Cirque” that is much larger than the valley below. – Continues to accumulate snow rather than melt, which forms glacial ice.
Any glacier must be at least 50 meters thick in order to move through its own weight. Glaciers are classified by their location, rate of movement, and appearance.
Classification of glaciers:
– Valley or Alpine Glaciers : As already stated earlier in this article, they tend to be small and originate in mountain valleys.
– Continental Glaciers: Originate from a dome of snow that is much larger than the valley below called a “Cirque.”
– Calving Glacier: Ice breaks off at the edge and forms iceberg s.
– Piedmont Glacier: A large expanse of glaciers that spread out and form a wide plain of ice.
The rate at which these glaciers move is determined by their location and the amount of snow accumulation (or lack thereof).
Normally, alpine glaciers move less than one meter per day while continental glaciers can move several kilometers in a year.
Along with snow and ice, glaciers also move vast amounts of debris such as rocks, dirt, and sand.
This is called glacial till or glacial debris. A single glacier can transport thousands of tons of debris as it moves. Glacial till may be piled up at the edges of glaciers in huge amounts of earth, gravel, sand, clay, and boulders called moraines.
Moraines: – Ridge of soil, gravel, sand, clay and boulders left behind as a glacier retreats. – Consists of glacial till or debris carried by the glacier.
Glaciers can form in any climate where there is significant snowfall and the temperature remains below freezing year round. Glaciers are found today on every continent except Australia and South America.
Due to the powerful force of glaciers, they have left an indelible mark on our planet’s geology. Most importantly, glaciers are responsible for carving the beautiful landscapes we see today.
