What is an iceberg and how does it form. Iceberg - what is it? How icebergs form. Water protection

Iceberg (German Eisberg, “ice mountain”) is a large free-floating piece of ice in the ocean or sea. Typically, icebergs break off from ice shelves. Since the density of ice is 920 kg/m³ and the density of sea water is about 1025 kg/m³, about 90% of the iceberg's volume is under water. Long-term snowfalls and compaction of the snow cover cause the “growth” of the iceberg, turning it into a collection of billions of tiny ice mirrors that reflect light.

Where do icebergs form?

In the northern hemisphere, their birthplace is Greenland, which constantly accumulates ice and, from time to time, sends the excess into the Atlantic Ocean. Under the influence of currents and winds, ice blocks are sent south, crossing the sea routes that connect North and South America with Europe. The length of their journey differs in different seasons. In spring they do not even reach 50º C. las., and in the fall they can reach 40º C. w. Transoceanic sea routes pass at this latitude.

An iceberg is a block of ice that can form off the coast of Antarctica. From this place their journey to the forties latitudes of the Pacific, Atlantic and Indian Oceans begins. These areas are not so popular among sea carriers because their main routes go through the Panama and Suez Canals. However, the dimensions of icebergs and their number here are much greater than those in the northern hemisphere.

Table-shaped icebergs

Having learned what an iceberg is, you can consider their varieties. Table-shaped ice floes are the result of the process of calving off large areas of ice shelves. Their structure can be very different: from firn to glacier ice. The color characteristics of an iceberg are not constant. Freshly broken snow has a white matte tint due to the large proportion of air in the outer layer of compressed snow. Over time, the gas is displaced by droplets of water, causing the iceberg to turn light blue.

A table iceberg is a very massive block of ice. One of the largest representatives of this type had dimensions of 385 × 111 km. Another record holder had an area of ​​about 7 thousand km2. The majority of table-shaped icebergs are orders of magnitude smaller than those indicated. Their length is about 580 m, height from the water surface is 28 m. On the surface of some, rivers and lakes with melt water can form.

Pyramid icebergs

The pyramidal iceberg is the result of ice landslides. They are distinguished by a peak with a sharp end and a significant height above the surface of the water. The length of ice blocks of this type is about 130 m, and the height of the surface part is 54 m. Their color differs from table-shaped ones in a soft greenish-bluish tint, but darker icebergs have also been recorded. The thickness of the ice contains significant inclusions of rocks, sand or silt, which fell into it while moving across the island or mainland.

Threat to seagoing vessels

Icebergs located in the North Atlantic Ocean are considered the most dangerous. Every year, up to 18 thousand new ice bodies are recorded in the ocean. They can only be seen from a distance of no more than half a kilometer. This is not enough time to turn away or stop the ship to prevent a collision. The peculiarity of these waters is that there is often a thick fog that does not dissipate for a long time.

Sailors are familiar with the terrible meaning of the word "iceberg". The most dangerous are old ice floes that have melted significantly and barely protrude above the ocean surface. In 1913, the International Ice Patrol was organized. Its employees are in contact with ships and aircraft, collecting information about icebergs and warning of danger. It is almost impossible to predict the movement of the ice giant. To make them more visible, icebergs are marked with bright paint or an automatic radio beacon.

The shape of an iceberg depends on its origin:

Icebergs from outlet glaciers are table-shaped with a slightly convex upper surface, which is dissected by various types of irregularities and cracks. Characteristic of the Southern Ocean.
Icebergs from cover glaciers are distinguished by the fact that their upper surface is practically never flat. It is slightly inclined, like a pitched roof. Their sizes, compared to other types of icebergs in the Southern Ocean, are the smallest.

Icebergs of ice shelves, as a rule, have significant horizontal dimensions (tens and even hundreds of kilometers). Their average height is 35-50 m. They have a flat horizontal surface, almost strictly vertical and smooth side walls.

In 2000, the largest currently known iceberg, B-15, with an area of ​​over 11,000 km², broke off from the Ross Ice Shelf as a result of mechanical ablation. In the spring of 2005, its fragment - iceberg B-15A - had a length of more than 115 kilometers and an area of ​​more than 2,500 km² and was still the largest iceberg observed.

The Ross Ice Shelf iceberg, named B7B, measuring 19 by 8 kilometers (an area larger than Hong Kong) was spotted in early 2010 by NASA and ESA satellite imagery about 1,700 kilometers south of Australia. The original size of this iceberg was about 400 square kilometers. It took iceberg B7B about 10 years to travel this far north. The coordinates of iceberg B7B at the beginning of 2010 are 48°48′ S. w. 107°30′ E. d.HGYAO.

Icebergs, especially table-shaped ones, are characteristic of the south polar region. In the northern subpolar regions, icebergs are more rare; icebergs of relatively small sizes from outlet and cover glaciers predominate among them. From the moment an iceberg of any kind is formed, the process of its destruction continuously occurs, especially actively in the seaward part of the ocean. Numerous forms of icebergs - pyramidal, inclined, round, with arches, rams - arise when they are destroyed. Sloping icebergs are a characteristic initial form of failure, especially of shelf table icebergs. The wave-cut underwater terrace, trying to emerge, lifts one edge of the iceberg. Sloping icebergs are very tall. The average lifespan of icebergs in Antarctic waters is about 2 years (with a volume of iceberg runoff into the ocean of 2.2 thousand km3/year and a total volume of them in the ocean of 4.7 thousand km3).

The color of an iceberg directly depends on the age of the iceberg: only the calved ice mass contains a large amount of air in the upper layers, and therefore has a dull white color. Thanks to the replacement of air with water droplets, the iceberg changes its color to white with a blue tint. Also, don’t be surprised by the pale pink iceberg.

An iceberg is a huge mass of ice that slides off a continent or island into the ocean or breaks off from the shore. This word is translated as Their existence was first reliably explained by M. Lomonosov. Due to the fact that approximately 10% less the main part of the iceberg (up to 90%) is hidden below the water surface.

Where do icebergs form?

In the northern hemisphere, their birthplace is Greenland, which constantly accumulates ice and, from time to time, sends the excess into the Atlantic Ocean. Under the influence of currents and winds, ice blocks are sent south, crossing the sea routes that connect North and South America with Europe. The length of their journey differs in different seasons. In spring they do not even reach 50º C. las., and in the fall they can reach 40º C. w. Transoceanic sea routes pass at this latitude.

An iceberg is a block of ice that can form off the coast of Antarctica. From this place their journey to the forties latitudes of the Pacific, Atlantic and Indian Oceans begins. These areas are not so in demand among sea carriers, because their main routes go through Panama and However, the dimensions of icebergs and their number here far exceed those in the northern hemisphere.

Table-shaped icebergs

Having learned what an iceberg is, you can consider their varieties. Table-shaped ice floes are the result of the process of calving off large areas of ice shelves. Their structure can be very different: from firn to glacier ice. The color characteristics of an iceberg are not constant. Freshly broken snow has a white matte tint due to the large proportion of air in the outer layer of compressed snow. Over time, the gas is displaced by droplets of water, causing the iceberg to turn light blue.

A table iceberg is a very massive block of ice. One of the largest representatives of this type had dimensions of 385 × 111 km. Another record holder had an area of ​​about 7 thousand km 2. The majority of table-shaped icebergs are orders of magnitude smaller than those indicated. Their length is about 580 m, height from the water surface is 28 m. On the surface of some, rivers and lakes with melt water can form.

Pyramid icebergs

The pyramidal iceberg is the result of ice landslides. They are distinguished by a peak with a sharp end and a significant height above the surface of the water. The length of ice blocks of this type is about 130 m, and the height of the surface part is 54 m. Their color differs from table-shaped ones in a soft greenish-bluish tint, but darker icebergs have also been recorded. The thickness of the ice contains significant inclusions of rocks, sand or silt, which fell into it while moving across the island or mainland.

Threat to seagoing vessels

Icebergs located in the North Atlantic Ocean are considered the most dangerous. Every year, up to 18 thousand new ice bodies are recorded in the ocean. They can only be seen from a distance of no more than half a kilometer. This is not enough time to turn away or stop the ship to prevent a collision. The peculiarity of these waters is that there is often a thick fog that does not dissipate for a long time.

Sailors are familiar with the terrible meaning of the word "iceberg". The most dangerous are old ice floes that have melted significantly and barely protrude above the ocean surface. In 1913, the International Ice Patrol was organized. Its employees are in contact with ships and aircraft, collecting information about icebergs and warning of danger. It is almost impossible to predict the movement. To make them more visible, icebergs are marked with bright paint or an automatic radio beacon.

The origin of the word goes back to the German "eisberg", which is most often translated as "ice mountain". A strict definition describes an iceberg as a floating or stranded massive piece of ice protruding more than five meters above sea level.

To more clearly understand the boundaries of the interpretation of the “massive” characteristic, we present three more related terms:

• ● piece of iceberg - a fragment of floating ice rising above the water by less than one meter and with a total area of ​​​​about twenty square meters;

• ● iceberg fragment - a fragment of floating ice rising above the water by more than one, but less than five meters, with a total area of ​​about one hundred to three hundred square meters;
• ● ice island - a large fragment of floating ice, rising above the water by more than five meters, a thickness of over twenty to thirty meters and a total area of ​​​​several thousand square meters to five hundred or more square kilometers.

Based on their appearance, icebergs are typically divided into:

• ● table-shaped (with a flat top);
• ● domed;
• ● pyramidal (close in shape to a pyramid);
• ● inclined;
• ● pointed;
• ● rounded.

How icebergs form

Under terrestrial conditions, icebergs form at the boundaries of glaciers that have access to the open sea/ocean: in the northern hemisphere, this occurs on the shores of Greenland, in the southern hemisphere, along the edges of the Antarctic ice sheet. The glaciers themselves are formed from solid precipitation falling in those places in the form of snow, ice needles, icy fog, etc. Due to the constant accumulation of ice material, the thickness of glaciers can reach several kilometers, and the pressure created contributes not only to the consolidation of scattered ice particles into a monolith, but also to its plastic deformation (slow flow) towards the water, like a river. After such a “solid river” emerges from the outlet, cover or shelf ice into the sea or ocean, due to fluctuations in the water surface, cracking occurs in the weakest places - and the formation of an iceberg of arbitrary size.

Why are icebergs dangerous?

It is important to clearly understand that due to the ratio of the densities of fresh ice (~920 kg/cubic meter) and sea water (~1025 kg/cubic meter), about 90% of the volume of any iceberg is hidden under water (see demonstration diagram-photomontage).

For ships near the iceberg, the danger is posed not only by its sharp parts visible and invisible from the surface (see the technical description of the world-famous Titanic disaster): while in the water, the iceberg is continuously and chaotically destroyed. Because of this, significant iceberg edge fragments may fall into the water, as well as overturns and other sudden movements of ice due to a sudden shift in the center of mass.

What is an iceberg?

Icebergs are pieces of ice that form on land and float in the sea or lake. Icebergs come in all shapes and sizes, from small ice cubes to chunks of ice the size of a small country. The term "iceberg" generally refers to a piece of ice larger than 5 meters (16 feet) across. Small icebergs, iceberg fragments, can be especially dangerous to ships because they are more difficult to detect. The North Atlantic and the waters surrounding Antarctica are the main habitat for most of the icebergs on Earth.

How do icebergs form and move?

Icebergs form from the ice of glaciers, ice shelves, or break off from an even larger iceberg. Icebergs move with ocean currents, sometimes stopping in shallow water or landing on the shore.
When the iceberg reaches warm waters, the temperature affects it. On the surface of an iceberg, warm air melts snow and ice, small lakes can form on it, which can seep through the iceberg, through cracks in it, thereby expanding them and destroying the iceberg itself. At the same time, warm water acts on the iceberg in its underwater part, gradually melting it and reducing its volume. The underwater part melts faster than the surface part.

Why is it important to study icebergs?

Icebergs pose a hazard to ships passing through the North Atlantic and the waters around Antarctica. After the Titanic tragically sank off Newfoundland in 1912, the United States and twelve other countries created the International Ice Watch to warn ships of the presence of icebergs in the North Atlantic.
The International Ice Survey uses aircraft and radar to track icebergs floating in the paths of major shipping lanes. In the US, the National ICE Center uses satellite data to monitor icebergs off the coast of Antarctica. However, it is only capable of tracking icebergs larger than 500 square meters (5,400 sq ft).

Icebergs can also serve as material for scientists to learn more about climate and ocean processes.
By studying the factors that cause icebergs to form, researchers hope to better understand the reasons that lead to the collapse of ice shelves.

Oceanologists also study icebergs because large volumes of cold fresh water can affect ocean currents and the circulation of ocean waters.

Biologists study icebergs to find out how they affect ocean life. How nutrients change in the ocean when an iceberg melts. Recent studies have shown that the waters around icebergs are filled with plankton and there are large concentrations of fish and other marine life.

Photos of icebergs:

I learned about icebergs in first grade. Our entire class, under the guidance of the teacher, “created” this very iceberg. The process was so exciting that I will remember it for the rest of my life. We froze regular tap water in a glass. And in a large jar, water was mixed with salt. The result was sea water. Then they took our fresh iceberg glass and dropped it into a jar of salt water. Ready! Most of our iceberg was under water and a little above the water, it seemed to be “hovering” in the water! Since then I've learned a lot of interesting things about icebergs, so...

What is an iceberg

An iceberg is a huge piece of ice floating in the ocean. Its homeland is the icy islands of the Arctic and Antarctica. Icebergs break off from glaciers sliding into the sea and begin to float. These ice mountains rise above the water only by one fifth of its size and can reach a height of up to 100 meters! Everything else is hidden under water. Their ice is fresh and very clean. Why doesn't the iceberg sink? The fact is that the density of salt water is greater than the density of fresh water. In addition, the density of sea water increases with decreasing temperature. So, at a temperature of 0°C it is 1000 kg/m³, and for ice 917 kg/m³. That is, the density of ice is slightly less, so it does not sink.

Icebergs can take on bizarre shapes:

• with a big and flat surface(formed in Antarctica). The area of ​​the largest “table iceberg” was 11,650 km²;
• domed, usually Greenland icebergs;
• dry dock type when the middle of the iceberg is hidden by water.

It's interesting what icebergs can swim through huge distances. For example, swim 4 thousand kilometers from the Arctic to Bermuda!

What colors are icebergs

It turns out there are icebergs not only whites, but also:

• blue color. The surface of such an iceberg is white. These are air bubbles, frozen between snow floes, sparkling in the sun. When the sun melts the top layer of ice, it becomes loose and melt water flows into cracks, where it freezes again. This is how the color blue turns out;
• striped. If the cracks fill with salty seawater, the iceberg will turn green;
• black. As the glacier moves, it captures black or brown rocks. They are usually at the bottom of the future iceberg. But if it turns over, a black fragment will be visible. Previously, encountering such an iceberg was considered a bad omen by sailors.

And the largest iceberg (in history) broke off from Antarctica this summer. It has an area of ​​more than 5 thousand km² and weighs almost a trillion tons!