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 to the south, crossing the sea routes that connect the Northern 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 chipped 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 northern part are considered the most dangerous. Atlantic Ocean. 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 thick fog, which 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.
11. Ice in the ocean.
© Vladimir Kalanov,
"Knowledge is power."
Ice is the solid phase of water, one of its aggregate states. Pure fresh water freezes at a temperature almost equal to zero (below zero by only 0.01-0.02 ° C). At the same time, water that has been purified in laboratory conditions to the maximum possible extent and is in a calm state can be cooled without forming ice to a temperature of minus 33°C. But the smallest piece of ice or other tiny object placed in such supercooled water will instantly cause rapid ice formation.
Normal ocean water, with a salinity of 35‰, freezes at minus 1.91°C. At a salinity of 25 ‰ (White Sea) water freezes at a temperature of minus 1.42°C, at a salinity of 20 ‰ (Black Sea) - at minus 1.07°C, and in the Sea of Azov (salinity 10 ‰) surface water freezes at a temperature minus 0.53°C.
Freezing fresh water does not change its composition. The situation is different when sea water freezes. Freezing begins with the formation of thin, elongated ice crystals, which contain absolutely no salt. Gradually, when the lumps of these crystals begin to freeze, salt gets into the ice.
The salinity of sea ice, i.e. The salinity of the water formed when it melts is on average about 10% of the salinity of ocean water. Over time, this figure decreases, and multi-year ice can be almost fresh.
The volume of ice is 9 percent greater than the volume of water from which it was formed, because... In the crystal lattice of ice, the packing of water molecules is ordered and becomes less dense. Therefore, the density of sea ice is less than the density of sea water and ranges from 0.85-0.94 g/cm 3 . That's why floating ice rise above the surface of the water by 1/7 - 1/10 of their thickness.
Strength sea ice noticeably lower than freshwater, but it increases with decreasing temperature and salinity of ice. Have the greatest strength multi-year ice.
Ice 60 cm thick, which forms on freshwater bodies in the depths of winter, can withstand a load of up to 15-18 tons, if, of course, this load is not applied concentratedly, but in the form of, say, a cargo platform on a caterpillar track, the supporting surface of which is approximately 2 .5 m2.
At this point we will make a small digression, but not at all lyrical. Lake Ladoga, as is known, has only a weak connection with the oceans and ocean ice. But we want to remind you that in 1941-1942 the ice “Road of Life” was laid along this lake, which saved the lives of many tens of thousands of people. Our young readers should definitely become familiar with the heroic and dramatic history of the construction and operation of this legendary road of life.
In the oceans, ice forms in high and temperate latitudes. In the polar regions, ice remains for several years. This perennial, so-called pack ice reaches its greatest thickness in the central regions of the Arctic Ocean - up to 5 meters. Sea ice begins to melt when its temperature exceeds minus 23°C. In the Arctic in summer, the thickness of ice due to the melting of its upper layers can decrease by 0.5-1.0 meters, but over the winter up to 3 meters of ice can freeze below. This multi-year ice is gradually carried by currents to temperate latitudes, where it melts relatively quickly. It is believed that the lifespan of Arctic ice that forms off the coast of Russia ranges from 2 to 9 years, and Antarctic ice lasts even longer. Largest sizes Ice cover in the oceans reaches at the end of winter: in the Arctic it covers an area of about 11 million km 2 by April, and about 20 million km 2 in the Antarctic by September. If we talk about permanent ice cover , then it makes up 3-4 percent of the total area of the World Ocean.
Ice cover may consist not only of fast ice, i.e. motionless ice frozen to the shore, but also moving drifting ice At strong wind, coinciding in direction with the sea current, drifting ice can travel a distance of up to 100 km per day.
Falling snow often creates large drifts on the ice. The snow gradually freezes, increasing the thickness of the ice cover. Sometimes hurricane-force winds break the ice, creating high hummocks. On such ice, if we talk about the Arctic, only polar bear, and even then with great difficulty.
But the ocean also contains ice that formed on land. These are the so-called icebergs - huge blocks fresh ice (German Eisberg - ice mountain). Icebergs are delivered to the ocean by continental glaciers at polar latitudes. The largest ice sheet on Earth is located in Antarctica. Its area is 13.98 million km 2, i.e. 1.5 times the area of Australia. At the same time, the area of the continent of Antarctica itself is estimated at 12.09 million km 2. the rest is accounted for by the ice that covers almost the entire shelf of Antarctica. Average thickness Antarctic ice is 2.2 km, and the largest is 4.7 km. The volume of ice is estimated at 26 million cubic kilometers. The enormous weight of ice pressed this continent into earth's crust. As a result, much of Antarctica's surface lies below sea level. The Antarctic glacier annually receives 2000-2200 km 3 of ice from snow and loses about the same amount to icebergs. Of course, this balance cannot be accurately calculated. Therefore, the scientific world does not yet have a clear answer to the question of whether the Antarctic glacier is increasing or decreasing.
Icebergs in the form of huge blocks, similar to mountains, slowly slide from the mainland into the sea, and then crash into the water with a roar. In Antarctica, the largest volume of ice in the form of icebergs is provided by two giant ice shelves advancing into the Ross and Weddell Seas. For example, the Ross Ice Shelf has an area exceeding 500 thousand km 2, and the ice thickness here reaches 700 meters. In the Ross Sea, this glacier approaches in the form of a huge ice barrier almost 900 km long and up to 50 meters high.
There are about 100 thousand icebergs constantly floating around Antarctica. Comprehensive monitoring, including iceberg monitoring, is carried out by 35 scientific stations operating here from different countries. Russia has 8 scientific stations here, the USA - 3, Great Britain - 2. Ukraine, Poland, Argentina and other states also have Antarctic scientific stations.
The international legal regime of Antarctica and other territories located south of 60° S is regulated by the Antarctic Treaty of December 1, 1959.
In the Northern Hemisphere, the main supplier of icebergs to the ocean is Greenland. It is believed that up to 15 thousand huge pieces of ice break off from the glaciers of this island every year. From here they sail into one of the busiest areas of the Atlantic Ocean.
Icebergs also break off from the glaciers of the islands of the Arctic Ocean - Franz Josef Land, Novaya Zemlya, Severnaya Zemlya, Spitsbergen and the Canadian Arctic Archipelago.
In general, glaciers occupy 16.1 million km 2 of land, of which 14.4 million km 2 are covered by ice sheets (85.3% in Antarctica, 12.1% in Greenland). In terms of area and volume of water, glaciers occupy the second place on Earth after the World Ocean, and in terms of fresh water content they exceed all rivers, lakes and groundwater combined.
Icebergs are table-shaped and pyramidal in shape. The table-shaped shape is characteristic of Antarctic icebergs, which are formed when they are separated from a huge mass of ice of a homogeneous structure. When glaciers move relatively quickly, the shape of the broken pieces often resembles a pyramid. As the underwater and surface parts melt unevenly, icebergs take on various, most bizarre shapes, and with loss of stability they can capsize.
Icebergs can reach enormous sizes. Especially large icebergs form from the ice shelves of Antarctica. In 1987, with the help of Earth satellites, an iceberg 153 km long and 36 km wide was discovered in the Ross Sea area.
An iceberg called B-15 broke off from the same glacier in 2000. This giant had an area of more than 11,000 km 2. If an ice floe of this area were on Lake Ladoga, then it would cover 63% of the surface of this large (17.7 thousand km 2) lake.
The mass of such giants can amount to hundreds of millions and even billions of tons. But this is clean fresh water, the shortage of which has long been felt by many countries.
The heat capacity of ice melting is very high. It takes 80 calories to melt 1 gram of ice, not including the heat it takes to warm the ice to zero degrees. It is no coincidence that projects for towing icebergs to the shores of such coastal states as Japan, Saudi Arabia, Kuwait, and the United Arab Emirates have long arisen. Calculations show that the iceberg is of “medium” size: 1 km long, 600 m wide and a total height of 300 m during the towing journey, for example, from Antarctica to Saudi Arabia will lose no more than 20% of its volume. The initial weight of such an iceberg would be about 180 million tons (in water it is much less). If towing an iceberg of this size remains a technically difficult task, then the delivery of relatively small ice fragments with a volume of 200-300 thousand cubic meters is quite doable and is already carried out from time to time by the countries mentioned above.
Having broken off from glaciers, icebergs, picked up by currents and driven by winds, sometimes float far beyond the polar regions. Antarctic icebergs reach the southern coasts of Australia, South America and even Africa. Icebergs from Greenland penetrate into the North Atlantic up to forty degrees north latitude, i.e. latitudes of New York, and sometimes further south, reaching the Azores and even Bermuda.
The cruising range of icebergs and the time of their existence in the ocean depend not only on the direction and speed of sea currents, but also on the physical properties of the icebergs themselves. Very large and deeply frozen (down to minus 60 degrees) Antarctic icebergs exist for several years, and in some cases even decades.
Greenland icebergs melt much faster, in just 2-3 years, because... they are not so large in size and their freezing temperature is no more than minus 30 degrees.
It is unnecessary to explain what danger floating ice mountains pose for shipping. More than once collisions with icebergs have led to disasters at sea. But none of these disasters can compare with the tragedy that took place at the beginning of the 20th century in the North Atlantic.
Nowadays, the danger of colliding with icebergs has decreased significantly compared to the times of the Titanic. On sea vessels, in ports, on artificial earth satellites, fairly reliable radar and other equipment is installed for tracking, alerting and warning about the danger of encountering icebergs. In the North Atlantic, where there are busy shipping routes, a special ice patrol . It warns ship captains about the locations of large icebergs. The International Ice Patrol includes 16 countries. His ships detect icebergs, warn about the location of icebergs and the direction of their movement. The functions of the ice patrol also include the fight against icebergs, which is carried out with the help of explosions, the use of incendiary bombs, dark coloring of ice blocks, for example, by applying a layer of soot to the surface of the iceberg to speed up the melting process, etc.
However, the measures taken cannot be exhaustive. Icebergs appear in the ocean according to the laws of nature. No one can completely guarantee sea vessels against ice hazards. The ocean is large and often fraught with dangers, for which it is always necessary to prepare in advance.
© Vladimir Kalanov,
"Knowledge is power"
Striped icebergs:
Steven Kazlowski captured these majestic natural ice sculptures carved by seawater and polar winds on the western tip of Antarctica. Breakaway icebergs float in Antarctic waters for years, and for years Mother Nature, like a skilled sculptor, creates intricate figures.
Colonnade in an iceberg - not photoshop!
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.
The nature of icebergs was first correctly explained by the Russian scientist Mikhail Lomonosov.
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.
In 2000, the largest known ice cap broke off from the Ross Ice Shelf as a result of mechanical ablation. at the moment iceberg B-15 with an area of over 10,000 km².
In the spring of 2005, its fragment - iceberg B-15A - was more than 115 kilometers long and over 2,500 square kilometers in area 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.
Icebergs of this size and so far from their source of origin have not been observed in the last hundred years.
It took iceberg B7B about 10 years to float this far north. The coordinates of iceberg B7B at the beginning of 2010 are -48.8, 107.548° S. w. 107° east long / 48.8° south w. 107.5° E. d..
If an iceberg blue, most likely it is more than 1000 years old.
The dark blue color is the so-called. “black” icebergs that have recently capsized in the water.
Icebergs pose a very great danger to shipping. One of the most famous examples collision of an iceberg with a ship - the sinking of the Titanic in 1912.
They are carried far away by sea currents. And it’s amazing - sometimes the ice mountains seem to float against the current.
This happens because only an eighth or ninth of the entire iceberg rises above the surface of the water, the rest is immersed deep in the water, where the current is sometimes opposite to that on the surface.
Icebergs can reach a height of 100m above the sea surface.
An ice mountain floating in warm waters is usually shrouded in dense fog - this is water vapor from warmer air condensing over its cold surface.
The most large icebergs are born from the giant glaciers of Antarctica.
From time to time, deep cracks form in the glacier, and it splits into separate blocks.
The birth of an iceberg is a spectacular sight. A huge mass of ice falls into the water with a roar reminiscent of a monstrous explosion.
Even a relatively small ice mountain, 150 m thick, 2 km long and half a kilometer wide, contains almost 150 million tons of fresh water, and of very high quality.
This amount of water would be enough for a whole month for such a gigantic city as Moscow, with a population of millions.
In the USA, projects are being developed to transport icebergs to the multimillion-dollar city of Los Angeles, to the port cities of South America, Africa, and Australia.
Once in the water, the iceberg sets off to swim.
Currents sooner or later carry it to warmer latitudes, where it is washed by warm waters and it slowly melts under the rays of the sun.
But especially large icebergs manage to move far to the south if they are Arctic icebergs, or far to the north if they are Antarctic.
In just one year, about 26 thousand icebergs break off from the Arctic ice cover.
During the year, approximately 370 icebergs pose a threat to navigation. Therefore, in the open ocean, they are constantly monitored by a special service.
The construction of inhabited research bases is practiced on icebergs.
It is already sometimes practiced to tow icebergs to dry areas.
Sources of information and some photographic materials.
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 chipped 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 that is dissected various types unevenness 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 rarer; 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, rounded, 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 ice mass that has broken off contains large number air in the upper layers, therefore it has a matte 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.
Last December, photographer Alex Cornell, during his expedition to Antarctica, was lucky enough to photograph an amazing iceberg of an unusual blue color. It turned out that the iceberg turned over and the part of the iceberg that is usually under water became visible. Very beautiful color, I have never seen anything like it before.
Video of how icebergs can turn:
Simply beautiful
After these photos, Osya and I talked a lot about icebergs, and here are different interesting facts things you can tell your children:
1. How are icebergs formed?
They break off from large shelf (i.e., floating or bottom-supported) glaciers.
You can launch a small boat and several frozen ice floes in colored water with foam. And conduct a study - what exactly is floating in front of the ship - just a giant ice floe or a real iceberg?
- In plastic molds (for example, from ice cream) you can freeze flat pieces of ice, if you do not pour a lot of water into them.
- Uneven ice will result if you freeze water in wrinkled plastic cups. It’s just better not to wrinkle them too much, otherwise they will crack.
- Separately, you can freeze water in special ice molds, and then these ice pieces will easily stick to each other and you can make different “icebergs.”
We checked whether the iceberg really does not sink, and how much it sinks into the water.
2. Types of icebergs. Icebergs are table-shaped, dome-shaped and pyramidal. An iceberg with a flat surface can easily be mistaken for an island. And it’s comfortable to live on if you’re a penguin.
There are also “dry dock” icebergs - the middle of such an iceberg lies below the surface of the water.
We tried to make icebergs different shapes, it turns out very funny. The best iceberg is made from ice in a salad bowl.
At the same time, we discussed the bottom of the iceberg. Scientists know of cases where icebergs drifted against the current. And Osya spent a long time guessing how this could be? The whole point is that only a third or fourth of the entire iceberg rises above the surface, while the rest is submerged in water, and there is so much of it that it is “controlled” by active underwater currents.
3. The largest iceberg:
In 2000, the largest known iceberg in history (B-15), measuring 295 km in length and 37 km, broke off the Ross Ice Shelf. This is very difficult to imagine, it seems to me.
4. It's interesting what these ice giants can do travel great distances. For example, icebergs from the Arctic float almost to Bermuda, located 4,000 km from their place of formation. But Antarctic icebergs can be seen in the area of the Brazilian city of Rio de Janeiro. And this is more than 5,000 km from the coast of Antarctica!
5. Floating so far icebergs can be very dangerous for shipping. Everyone knows tragic fate the English passenger liner Titanic, which collided with a huge iceberg on April 14, 1912, and as a result sank. Soon after, the International Ice Patrol was created to monitor the movement of icebergs and warn ships of possible danger. And since the beginning of the work of the ice patrol in the North Atlantic, not a single person has died from collisions with icebergs.
It is very interesting that it turns out that there is an iceberg tugboat. The Atlantic Eagle is battling large icebergs in the ocean.
Its only task is to move the iceberg a few degrees from the undesirable course. When a tugboat approaches an iceberg, its crew uses radar to obtain an image of the underwater part of the iceberg. Then the tug goes around it, bending around the ice floe and unwinding hundreds of meters of powerful cable. Having made a loop, both ends are secured to the boat with huge staples. Then, increasing the power of the vessel, they move the iceberg from its place. All this can be very dangerous, because if the iceberg suddenly decides to capsize, it will cause a huge wave or break apart, and this can lead to the sinking of the ship.
6. Iceberg color
Young icebergs white, they consist of ice and air bubbles. These air bubbles form in the glacier from which the iceberg breaks off. When snow is compressed and turns into ice grains, some of the air is also “pressed” into the ice and can occupy up to 15% of the iceberg’s volume. When a glacier moves, cracks form in it. They are filled with water, which, unlike snow, freezes without bubbles. Then blue streaks appear in the iceberg: this is ice free of air.
This is how striped icebergs appear.
They write that in this iceberg, while drifting, sea water and algae got into the cracks and froze:
There are also “black” icebergs: they form when a glacier begins to move and “removes” layers of rock or soil from the surface, which later form black in its thickness. And the black color in icebergs may be a remnant of the volcanic dust that covers their mother glaciers.