Glaciers are an extraordinary miracle of nature that slowly moves across the surface of the Earth. This accumulation of eternal ice captures and transports rocks along its path, forming unique landscapes such as moraines and karas. Sometimes the glacier stops moving and the so-called dead ice forms.
Some glaciers, moving a short distance into large lakes or seas, form an area where they break up and, as a result, drift icebergs.
Geographical feature (meaning)
Glaciers appear in places where the accumulated mass of snow and ice significantly exceeds the mass of melting snow. And after many years, a glacier will form in such a region.
Glaciers are the largest reservoirs fresh water on the ground. Most glaciers accumulate water in winter season and give it away as melt water. Such waters are especially useful in the mountainous regions of the planet, where such water is used by people who live in areas where it rains. a small amount of atmospheric precipitation. Also melt water glaciers are sources for the existence of flora and fauna.
Characteristics and types of glaciers
According to the method of movement and visual outlines, glaciers are classified into two types: cover (continental) and mountain. Ice sheet glaciers occupy 98% of total area planetary glaciation, and mountain glaciations - almost 1.5%
Continental glaciers are giant ice sheets located in Antarctica and Greenland. Glaciers of this type have flat-convex outlines that do not depend on the typical topography. Snow accumulates in the center of the glacier, and consumption occurs mainly on the outskirts. The ice of the cover glacier moves in a radial direction - from the center to the periphery, where the ice that is afloat breaks off.
Mountain type glaciers - small sizes, But different forms, which depend on their content. All glaciers of this type have clearly defined areas of feeding, transportation and melting. Nutrition is carried out with the help of snow, avalanches, a little sublimation of water vapor and snow transfer by the wind.
The largest glaciers
The largest glacier in the world is the Lambert Glacier, which is located in Antarctica. The length is 515 kilometers, and the width ranges from 30 to 120 kilometers, the depth of the glacier is 2.5 km. The entire surface of the glacier is rugged big amount cracks The glacier was discovered in the 50s of the twentieth century by the Australian cartographer Lambert.
In Norway (Svalbard archipelago) there is the Austfonna glacier, which leads the list of the largest glaciers in the Old Continent by area (8200 km2).
(Vatnajökull Glacier and Grimsuod Volcano)
In Iceland there is the Vatnajökull glacier, which ranks second in Europe in terms of area (8100 km2). The largest in mainland Europe is the Jostedalsbreen glacier (1230 km2), which is a wide plateau with numerous ice branches.
Melting glaciers - causes and consequences
The most dangerous of all modern natural processes is the melting of glaciers. Why is this happening? The planet is currently heating up - this is the result of the release of greenhouse gases into the atmosphere that are produced by humanity. As a result, the average temperature on Earth also rises. Since ice is the repository of fresh water on the planet, its reserves will sooner or later run out with intense global warming. Glaciers are also climate stabilizers on the planet. Due to the amount of ice that has melted, salt water is evenly diluted with fresh water, which has a special impact on the level of air humidity, precipitation, and temperature indicators in both the summer and winter seasons.
Did you know that our planet is covered with ice on eleven percent of its territory? Yes, these white areas visible from space cover an area of more than 16 million square kilometers. So, despite the concerns of environmentalists about global warming, the Earth is still largely covered in ice. They contain approximately two-thirds of all fresh water - which is 25 million cubic kilometers of ice. Scientists have calculated that if it all melted, the level of the world's oceans would rise by tens of meters, which would lead to great destruction and the death of entire states. But what is a glacier? Can a snow slide, watered with water, be called by this proud name? In this article we will look at how glaciers form, how they live and where they die. We will look at the meaning of terms such as tongue, firn, moraine. We will also learn how glaciers are classified according to various catalogs.
What is a glacier: definition
Encyclopedias, explanatory dictionaries and textbooks describe the term differently. And equally incomprehensible. Here, for example, is the following definition: “The mass of ground natural ice of atmospheric origin, which has independent movement caused by gravity.” Let's try to explain accessible language What is a glacier? This is snow compressed under its own weight, which accumulates for years in areas with low temperatures (polar latitudes or high-altitude zones), and then, having increased in volume, slides to other areas (into valleys, into the sea). If this explanation seems unclear to you, then let us explain it more simply. There are areas where the air temperature is always below zero. Precipitation there falls in solid form: snow, frost, hoarfrost, and the passage of cold clouds. As they accumulate, they are pressed under their own weight, and a glacier is formed. It begins to live its own life, sliding off tongues or breaking off like icebergs.
Snow, firn, ice
In the mountains you often see snow-white shining peaks rising above green valleys. But if winter has come into its own in the upper reaches, this does not mean that glaciers have formed. The first snow, like powdered sugar, dusting the tops, is too light and fluffy. Thanks to its openwork structure, it is easily heated. During the day or summer (if it happens very high or near the Earth's poles), fluffy snowflakes melt. Then they freeze again. But these are no longer the former openwork stars. Snowflakes turn into hard balls - firn. This grain accumulates over the years. Under its own weight, the firn begins to flatten and changes its structure again. So we have come to an understanding of what a glacier is. The definition of this term concerns specifically the third, final phase of the transformation of solid sediments.
Classification
People have long been interested in what glaciers are. Researchers noticed that each of them has its own geophysical or hydrothermal features. Therefore, there was a need to classify glaciers. At first, there was a certain discrepancy in cataloging. In some countries, morphological features were taken into account, in others, hydrothermal characteristics were the decisive criterion. There is now a World Glacier Watch. This authoritative international body defines what a glacier means and decides which WGMS group it belongs to. However, it is launched new project according to the classification of these natural objects - GLIMS. The USSR Glacier Catalog is still used in our country.
Types of glaciers
Depending on the region of formation, these masses of hardened snow are divided into ground (cover), mountain and shelf. The first type occupies the most large area. Such glaciers formed near the poles. The largest is the Antarctic cover. Its area is more than 13 million square kilometers. In fact, the glacier covers the entire continent of Antarctica. The second largest area is occupied by the cover of Greenland - 2.25 million km 2. Mountain glaciers are also called alpine glaciers. They are formed in areas of altitudinal zonality. They are found not only in the Alps, but also in the Himalayas, the Caucasus and even in Africa (Kilimanjaro). Well, what are ice shelves? Shallow waters of polar latitudes frozen to the bottom. Sometimes glacial tongues slide into the water and break off there, forming icebergs. They can migrate, carried by wind and current, many hundreds of kilometers from their place of birth. The largest iceberg in the world is located off the east coast of Antarctica. This is the Lambert Glacier. Its length is 700 kilometers.
Glacier structure
Experts distinguish two areas in the snow mass: nutrition, or accumulation, and ablation. They are separated by the so-called snow line. Above it, the amount of solid precipitation exceeds the sum of evaporation and melting. And below the snow line, the glacier begins, albeit slowly, to die. After all, the term “ablation” is translated from Latin as demolition, taking away. You can also describe what a glacier is and its structure in this way. This firn field is the area where snow undergoes its metamorphosis. Tongues come out of it. Sliding down into areas with higher temperatures, they melt, feeding mountain lakes and streams. But since the glacier tongues have a gigantic mass, they squeeze out the earth bed, drive boulders in front of them, and drag stones. Such “run-in” products are called moraines.
Glaciers on the move
The speed at which tongues move depends on many factors. The terrain is fundamental. For example, in flat Antarctica, where low temperatures turn the entire continent into a huge firn field, the glacier grows only in height. The thickness of the layer in some places reaches almost five kilometers! But in the Alps, tongues slide at a speed of fifty meters per year. The fastest is the Columbia Glacier on the Alaska Peninsula. Its speed is truly amazing - twenty meters per day! Tongues move along trough valleys, which they themselves create by scraping out the foothills. Sometimes glaciers are limited only to the firn field: having occupied a hollow on the northern spur of the mountain, the mass of snow simply does not melt in the summer and “survives” until winter, already compressed.
What are pulsating glaciers
Sometimes the mass of snow doesn't move anywhere. Scientists call this “dead ice.” But sometimes violent processes associated with a restructuring of the dynamic regime begin to occur inside the snow mass. At the same time, the total mass of the glacier does not change. Friction on the bed causes the blocks to crush. And this causes periodic (pulsating) changes in the speed of language advancement. They begin to “flow” rapidly, causing destructive ice mudflows. There is a certain periodicity to such sudden changes. That's why scientists came up with the term "pulsating glaciers." The frequency of such revolutionary changes may vary. For example, the Caucasian pulses approximately once every 50 years (1902,1969, 2002), and in the Pamirs Medvezhiy - every decade (1963, 73, 89).
Mass balance
This is the main characteristic of a glacier, in addition to its area, length of tongues and speed of movement. Mass balance - what is it? The glacier grows in cold weather, when it receives a large amount of solid precipitation, and decreases in summer. The mass of snow turned into firn that fell from the previous surface in August until the end of the cold weather is called the winter balance. Accordingly, summer is how much ice melted from the spring warmth to the first snow. Well, the annual mass balance is the sum of accumulation and ablation.
Snow tends to melt. On the eve of spring, this is considered normal. However, there are so-called glaciers that can not only succumb to melting, but also cause destruction and a lot of trouble. It's about not about the sheet of ice that covers the rivers and lakes where people skate in winter. What I want to talk about has more complex structure and the structure of emergence.
A glacier is associated with cold or snow. Consequently, it is formed precisely from this type of sediment. The next thing that is common and logical is the place where they appear. Of course, most often you can meet a gigantic mass of ice in high mountains or polar regions. But how this layer of ice is formed is a real art. Creativity usually requires enormous effort and incredible patience, which is what we see in the formation of glaciers. They appear through the accumulation of precipitation in the form of snow and their further compaction. The end result, by the way, resembles the very cover that I spoke about in the introduction.
The wide and limitless possibilities of nature.
Of course, such a phenomenon as the formation of glaciers is truly a miracle. Indeed, one has only to look at this ice mass; its scale will amaze everyone without exception. It is known that such formations cover a huge area of our earth's surface. This leads to the following thought: what is causing the growth of glaciers?
The answer to this question is their movement. But having heard this answer, a question involuntarily arises: how does the process of movement proceed? Offset y different types Glaciers flow in different ways, because this is influenced by different factors. The most influential include: - The area of the formation itself;
- The surface on which sliding occurs;
- Time of year, and therefore temperature;
- Presence of obstacles.
Provided that there are no factors impeding the movement of glaciers, its movement speed can achieve high results. That is why such ice coverings are considered to be very dangerous. In addition, when all the glaciers that currently exist melt, all nearby villages and cities will be drowned, which also warns us that nature is capable of both creating and destroying. 
" is formed by analogy with the French "glacia", which, in turn, is of Latin origin and means "ice". A glacier is a huge accumulation eternal ice, which most often moves slowly along the surface of the Earth, moving under the influence of its own gravity. Only those ice masses that have existed for a relatively long time can be called a glacier. They form in places where the air temperature rarely rises above 0°C. Snow and other precipitation accumulate to form a glacier, and melting occurs more slowly than ice accumulation. The glacier forms very slowly, over decades and centuries, little by little. As a result, huge masses of very hard, compressed ice are formed: in its characteristics it is very different from regular ice, formed on the surface of reservoirs. The process of ice formation is called glaciation, and glaciology studies these processes and everything related to glaciers.
Glaciers vary in shape and size, as well as other features. There are glaciers of slopes, peaks, valleys, cover glaciers, mountain cover glaciers, shelf glaciers and many other types. Geophysical classification divides these ice masses into polar, subpolar and temperate, depending on their climatic position.
The most famous glaciers
Most of the glaciers on our planet are located at the poles, but some also exist in tropical mountainous regions. Glaciers are found on all continents except Australia. They are formed at very high altitudes, usually above 5-6 thousand meters above sea level.
Glaciers cover almost all of Greenland - up to 75% of its area - and all of Antarctica. The southernmost area contains the largest amount of ice - the supply of fresh water on the planet. There are glaciers up to 5 thousand meters thick here. Off the coast of Antarctica, ice constantly separates from the massif and forms icebergs.
Other famous glaciers are spread throughout the planet. Baltoro is one of the most famous, as it has the greatest length: the length is about 62 kilometers. Baltoro is located in Pakistan, it is surrounded by the Karakoram Mountains and is located at an altitude of 3400 meters above sea level.
The Kilimanjaro glacier does not differ in size or any other features. But this is a unique phenomenon - it is located near the equator, in the heart of Africa. It is located at the top of Africa's highest mountain, Kilimanjaro. Scientists have found that it was formed more than eleven thousand years ago, but today, due to warming, it is gradually decreasing. Now its area is about two square kilometers.
What is a glacier, how is it formed and what types of glaciers are there?
Exist different types surface of our planet: solid soil, water surfaces... But there are also enormous glaciers that cover 16.3 million km 2 of our Mother Earth.
What is a glacier?
A glacier is a huge mass of ice that was formed from precipitation (snow) under the influence of low temperatures and compaction of these sediments. Glaciers grow over the years, and under the influence of heat they melt, and small or large pieces break off from them and float across the sea or ocean. Such debris is called icebergs.
(Photo of glacier No. 1)
What is a glacier, can it move?
Glaciers move under the influence of gravity, some move very slowly or stop moving altogether, but some move surprisingly quickly, taking the form of a stream or system of streams, because the ice, until it hardens into a dense block, flows like viscous lava, the movement of already formed glaciers is due to force gravity, movement of lithospheric plates and atmospheric changes.
(Photo of glacier No. 2)
What is a glacier, forms of a glacier
Glaciers can be in the form of a stream or system of streams, a shield or dome, or a floating slab if they hang over expanses of water. For example, the giant glacier systems of Greenland and Antarctica are pancake-shaped, thick in the middle and thinner towards the edges.
(Photo of glacier No. 3)
What is a glacier, places of formation
As you may have guessed, glaciers usually form in places where there is a lot of water and freezing temperatures. The lower the temperature and the longer it persists, the greater the chance of the glacier to live longer. Glaciers can be found in middle and high latitudes. Where does the negative temperature stay? all year round and a lot of snow falls, glaciers accumulate their mass over many years, for example, pack ice in the Arctic Ocean or around Antarctica, as well as glaciers underground in the permafrost zone, where the bowels of the earth are always negative temperatures or glaciers in the mountains at the very tops and at the poles of the earth.
(Photo of glacier No. 4)
What is a glacier and how is it formed?
Let's take for example the situation in the mountains, a lot of snow falls, this snow becomes compacted and does not have time to melt within summer period, it turns into ice, filling a small depression in the mountains. The newborn glacier grows year after year during prolonged cold spells and begins to slowly move down the mountainside; it extends down something like an icy tongue. In summer, this “tongue” melts and forms a stream of water - this is the beginning of a glacial river. The upper region of the glacier is called the region of nutrition, that is, the accumulation of ice, and the lower part is called the region of consumption (ablation - deprivation). And between them there is such a narrow zone, which is called the boundary of nutrition or equilibrium, since how much snow accumulates here is consumed in the summer with warming. This border is very clearly visible in summer, the tongue below is without snow, and at the top it is with snow. If the boundary rises upward from year to year, then the climate changes to warming, and then the glacier thins and retreats upward. If the equilibrium zone moves downward, this means cooling, then the glacier gains mass, gets thicker and extends its “tongue” further down the slope. It turns out that the glacier is an indicator of climate change on earth. Glaciologists are scientists who study and observe glaciers, publishing their observations from different mountainous regions of the globe.
What is a glacier and what types of glaciers are there?
Glaciers are different: ground, which press with their mass on the soil surface above sea level and maritime glaciers that are below sea level, these underwater glaciers inside are sea sheets with ice streams that overlie a rock bed, outside they are floating shelf
(Photo of glacier No. 5)
Distinguish mountain And integumentary. Their sizes vary - from several hundred square meters up to a million square kilometers or more.
(Photo of glacier No. 6)
What is a glacier, the influence of glaciers on climate
Glaciers accumulate most of the fresh ice on Earth (98.95%); they cover 10.9% of the land. With their movement and growth, glaciers significantly influence changes in relief and surface height, and fluctuations in the level of the World Ocean, which reaches hundreds of meters. Scientists believe that this influence of glaciers changed the earth's climate so much that there were periods of global cooling, which are called ice ages. How many of these periods there were, opinions differed. Evolutionists, who believe in a million-year history of the Earth, argue that there were several ice ages. Creationists, who believe in the creation of the Earth by Intelligent Design, believe that there was only one Ice Age after the Flood. Where is the truth and where is guesswork, figure it out for yourself.
