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Where did so much sand come from? How is sand formed? Traveling grains of sand

Material about sands and deserts (more like thinking out loud), based on the data that we have today...

(From the Arabic "sahra" - desert)

Tell me, where do we have the most sand?

That's right... underwater, in the oceans and seas. Deserts are the bottom of seas and oceans. Yes Yes exactly. As a result of movements of the earth's crust, something went down and something rose to the top. But this process took more than one thousand years.

As you know, deserts occupy about a third of the planet's landmass. But it happens that the desert you see is not really a desert at all. Today you will learn about several such places on our planet.

Sahara

Almost the entire north of Africa is occupied by the world's largest desert - the Sahara. Now its territory extends over 9 million square kilometers, and the semi-desert Sahel adjoins to the south. Temperatures in the Sahara reach a prohibitive 60 degrees, and yet there is life there. Moreover, life in this territory not only hid from the bright sun behind every grain of sand, emerging only at night. Even 2700 - 3000 years ago, forests grew in this place, rivers flowed and the windows of countless lakes sparkled.

And about 9,000 years ago, a very humid climate prevailed in the Sahara Desert. And for several thousand years it was home to people, as well as many steppe and forest animals.

Photographer Mike Hettwer kindly shared his photographs of what remains of the green era of the Sahara Desert. (© Mike Hettwer).

During an expedition to find dinosaur fossils in the state of Niger in West Africa, photographer Mike Hettwer discovered a large burial containing hundreds of skeletons from two different cultures, the Kiffian and the Tenerian, each thousands of years old. Hunting implements, ceramics and bones of large animals and fish were also found.

An aerial view of the desert and the barely visible tents of a small group of archaeologists conducting excavations. Looking at this photo, it’s hard to believe that several thousand years ago this was the “green” Sahara.

This is a 6,000-year-old skeleton found that, for unknown reasons, had its middle finger in its mouth. At the time of the excavation, the temperature in this part of the Sahara Desert was +49 degrees, far from the temperature in the “green” Sahara 9,000 years ago.

Six thousand years ago, a mother and two children died at the same time, and were buried here holding each other's hands. Someone took care of them, as scientists discovered that flowers had been placed on top of the bodies. It is not yet known how they died.

This 8,000-year-old rock carving of a giraffe is considered one of the finest petroglyphs in the world. The giraffe is depicted with a leash on its nose, which implies a certain level of domestication of these animals.

Interestingly, ancient sands can store information. Optical luminescence studies of sand carried out in a US laboratory have proven that the bottom of this lake was formed 15,000 years ago during the last ice age.

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Most deserts were formed on geological platforms and occupy the oldest land areas. Deserts located in Asia, Africa and Australia are usually located at altitudes from 200-600 meters above sea level, in Central Africa and North America - at an altitude of 1000 meters above sea level. Most deserts border or are surrounded by mountains. Deserts are located either next to young high mountain systems (Karakum and Kyzylkum, the deserts of Central Asia - Alashan and Ordos, South American deserts), or with ancient mountains (Northern Sahara).

Something unpleasant, perhaps even the very word “desert” is terrible.

She leaves no hope, decisively declaring that there is nothing here and cannot be. There is emptiness here, desert. And indeed, if we summarize even the brief information about the desert that has already been reported, the picture will not be very cheerful. There is no water; several tens of millimeters of rain or snow fall per year, while other areas receive an average layer of moisture of many meters per year. In the summer there is scorching heat, forty or even more degrees, and in the shade, and in the sun it’s scary to even say - the sand heats up to eighty. And mostly very bad soils - sands, cracked clay, limestone, gypsum, salt crusts. The desert stretches for many hundreds of kilometers, no matter how much you seem to walk or drive, it is still the same lifeless land.

It’s hot, there’s no water, there’s no one for tens of kilometers... But it’s still beautiful.

The insane stuffiness subsides only at night, when the sands cool down.

Sand - so what is it? - silicon dioxide, that's what it is. Sand from the bottom of an ancient sea - ocean. I don’t even know how long ago the desert was a sea. It's hard to say for sure. There is some kind of panic with dating today. But 12,000 years ago there was a completely different world here. The paintings on the walls of the cave depict a tropical paradise where people hunted antelopes, hippos, and elephants. An abundance of food, thousands of hunters and gatherers - that's what was in this blooming savannah, but not only here.

This is confirmed by photographs taken by the Space Shuttle in different ranges, which show that riverbeds that once stretched across the entire Sahara Desert are buried under the sand.

North Africa was inhabited.

Where did this green world come from here? The answer lies beyond this place. The Earth's orbit is not stable. In ancient times, a slight deviation of the Earth from its axis caused global changes. One hundred thousand years ago the deviation was only one degree, but for the Earth it had a catastrophic effect. The territory has moved a little closer to the sun. And that changed everything...

Five thousand years ago, the earth's axis again deviated from its trajectory, which led to disastrous consequences for the Sahara. Deadly sands have returned to the place where life flourished. For the people living here, this was the beginning of the apocalypse. Those who managed to survive moved to the western part of the desert, where the last patch of vegetation remained - the Nile River.

This single source of water provided life for the millions of people who settled on its banks. These were the ancient Egyptians. Their great civilization arose as a result of catastrophic climate change.

The Sahara is the largest and hottest desert. Theoretically, there are more than a million trillion grains of sand. This sand seems ordinary, but to experts it is unique. Sandboarding champions claim that this is the most “slippery” sand. In addition, this is the oldest sand on the planet.

225 million years ago the Sahara was much larger.

She was part of a planet that looked completely different than it does now. Almost the entire surface of the world consisted of one continent. It was the ancestor of the Sahara Desert. A huge part of land with an area of 30 million square kilometers was called Pangea. Today, evidence of the existence of this ancient desert is found all over the world, even in places where you least expect to see it.

In this lifeless environment, scientists made one of the most amazing discoveries in the entire history of the Sahara. A huge ocean in the middle of the desert. There used to be rivers and lakes there, but that was a very long time ago. The Sahara Desert was much larger. The discovery began with the discovery of one of the largest creatures on the planet. It was the skeleton of a Paralititan, the largest dinosaur. It weighed approximately 40-45 tons. In addition, irrefutable evidence of the existence of marine life in the vast desert space was found: shark teeth, turtle shells. 95 million years ago, a huge ocean stretched across the entire territory of North Africa. Scientists call it the Tethys Sea.

Paralititan

How much did such a giant need to eat in order to support itself..? This indicates that there was plenty of green food in this territory.

100 million years ago the continents were still moving in different directions. Africa gradually separated from the rest of the world.

As soon as it separated, 80 trillion liters of water rushed into the vacated space. Water flooded the earth and formed new huge seas.

Life flourished along the coast and for more than 60 million years, the Sahara remained one of the greenest and most fertile places on Earth. But the same forces that gave birth to the sea of Tennis also destroyed it.

As Africa moved across the globe, the continent experienced enormous tectonic stress. In the blink of an eye, the Tethys Sea flowed north towards the Mediterranean Sea. A rapid stream of water formed. His power cut a channel through the rock, creating a chasm like the Grand Canyon.

This one fissure will create something that will change the course of human history. The landscape of the Sahara Desert is varied. The line between life and death is very thin. But even here, among 5.5 million km² of sand, there is something amazing - the most fertile arable land.

The banks of the Nile extend for 3 km. This thin strip supports a population of 1 million people. But the mighty river exists here only thanks to a clash of natural forces that occurred a thousand kilometers south of here. Here the monsoons and rains of equatorial Africa move south to meet the snowmelt of the Ethiopian highlands.

Every year, billions of gallons of water overflow the banks of the Nile, flooding the country with valuable silt and minerals, some of nature's best fertilizers.

Beyond this area, there is a struggle for survival. Only a few plant species have adapted to desert life. Palm trees have developed wide, shallow roots that only need a little moisture. The leaves of the grass have become thinner, which reduces the evaporation of precious liquid. Even humans have adapted to live in these harsh conditions.

Nomads live in this desert. To survive, they use unique geological structures - oases. Wonderful water sources hidden among the dunes. These natural reservoirs contain liquid that has accumulated here for several million years. This is the most efficient way to store water on the planet.

The secret of oases in the unique sand of the Sahara. Usually water is quickly absorbed, penetrating deep into the ground through the sand. But the Sahara Desert has the smoothest and roundest sand on the planet. Sand grains, polished by the wind over millions of years, are compressed and compacted. This retains moisture and water is not absorbed anywhere.

The Egyptian oases have enough water to supply the Nile River for 500 years. These oases bring life to the desert, but human intervention upsets the delicate balance of life in the desert.

Once people move here, construction, pollution and agriculture destroy the topsoil and they disappear. Human civilization increases pressure on the environment, changing its balance.

Now the desert is growing by 80,000 km² per year. This growth is dangerous.

Light sand in the desert reflects heat into the atmosphere. The atmosphere is getting hotter. Clouds are more difficult to form and without rain the desert becomes even drier. The deadly reflector is a global problem, as these events affect people not only in North Africa. Everything that happens in the Sahara affects people living thousands of kilometers away.

The history of the Sahara is more than just the history of the North African desert - it is the history of our planet. We are only beginning to understand the significance of the complex interactions that occur in remote parts of the world. But the Sahara plays a central role in the Earth's fragile ecology. The answer lies in its location and life-giving properties that can change the whole world.

So where does sand come from in such quantities?

The origin of deserts can be determined from the data of geology, hydrogeology and paleogeography of the region, historical information, and archaeological works. Images of the Sahara from space show light-colored sands extending in the direction of prevailing winds from dry valleys. And this is not surprising. Because the main source of sand in the desert is alluvial deposits, river sediments. ( Alluvium (lat. alluviō - “sediment”, “alluvium”) - unconsolidated sediments)

How is sand formed? (Traveling grains of sand)

The ancient Greek philosopher-mathematician Pythagoras once puzzled his students by asking them the question of how many grains of sand there are on Earth.

In one of the tales told by Scheherazade to King Shahryar during 1001 nights, it is said that “the armies of the kings were countless, like grains of sand in the desert.” It is difficult to calculate how many grains of sand there are on Earth or even in the desert. But you can quite easily determine the approximate number of them in one cubic meter of sand. Having calculated, we find that in such a volume the number of grains of sand is determined by astronomical figures of 1.5-2 billion pieces.

Thus, Scheherazade’s comparison was at least unsuccessful, since if the fairy-tale kings needed as many soldiers as there are grains in just one cubic meter of sand, then for this they would have to call the entire male population of the globe under arms. And even this would not be enough.

Where did countless grains of sand come from on Earth?

To answer this question, let's take a closer look at this interesting breed.

Vast continental spaces of the Earth are covered with sand. They can be found on the coasts of rivers and seas, in the mountains and on the plains. But especially a lot of sand has accumulated in deserts. Here it forms mighty sandy rivers and seas.

If we fly in an airplane over the Kyzylkum and Karakum deserts, we will see an immense sand sea. Its entire surface is covered with mighty waves, as if frozen “and petrified in the midst of an unprecedented storm that engulfed colossal spaces.” In the deserts of our country, sand seas occupy an area exceeding 56 million hectares.

Looking at sand through a magnifying glass, you can see thousands of sand grains of different sizes and shapes. Some of them have a round shape, others have irregular outlines.

Using a special microscope, you can measure the diameter of individual grains of sand. The largest of them can be measured even with a regular ruler with millimeter divisions. Such “coarse” grains have a diameter of 0.5-2 mm. Sand consisting of particles of this size is called coarse sand. The other part of the sand grains has a diameter of 0.25-0.5 mm. Sand consisting of such particles is called medium-grain sand.

Finally, the smallest sand grains range from 0.25 to 0.05 in diameter. mm. It can only be measured using optical instruments. If such grains of sand predominate in sand, they are called fine-grained and fine-grained.

How are grains of sand formed?

Geologists have found that their origin has a long and complex history. The ancestors of sand are massive rocks: granite, gneiss, sandstone.

The workshop in which the process of transforming these rocks into sand accumulations takes place is nature itself. Day after day, year after year, rocks are subject to weathering. As a result, even such a strong rock as granite disintegrates into fragments, which become more and more crushed. Some of the weathering products dissolve and are carried away. The minerals that are most resistant to atmospheric agents remain, mainly quartz - silicon oxide, one of the most stable compounds on the Earth's surface. Sands may contain feldspars, micas and some other minerals in much smaller quantities. The story of grains of sand does not end here. For large aggregations to form, the grains must become travelers.

(I’ll say right away that this version of the scientists does not suit me - the scientists are being dark, oh they’re dark)

And this one doesn't fit either...

“Where does sand come from?”- The short answer is: grains of sand are pieces of ancient mountains.

But this one seems to fit:

Desert sand- this is the result of the tireless work of water and wind. It comes mainly from ancient oceans and seas. For millions of years, waves ground coastal rocks and stones into sand. During the development of the Earth, some seas disappeared, and in their place huge masses of sand remained. Winds blowing in the desert separate the light river sand from the pebbles and often carry it over long distances, where sandy mounds are formed. The sand may also come from the sandbanks of rivers that once flowed through deserts, or it may come from rocks that have weathered into sand.

(But let’s imagine how much time it takes to “grind” the rocks so that there is so much sand?)

So that the reader understands where I’m going with this, here’s a hint:

Sand is time.

Time of planet Earth. (from the moment of its inception, foundation) +/- (like all watches in the world)

We can say that every grain of sand has its own unique story. Only here is a key to pick up in order to get data from this sand array.

# - If you understand that water was a primary or secondary substance during the creation of our world, then another substance, solid (stone, rock) interacted with water, rubbed, rolled, along the bottom of the seas, oceans, and was carried by the wind..

How long (millions of years) did it take water to make a grain of sand from pieces, fragments of silicon, granite, ...? - and you try to imagine...

Another version (not mine)

Origin of the Sahara Desert and its sand:

Sand in air currents, particularly sand carried from the African Sahara across the Atlantic to South America, helps support the amazing diversity of life in the jungles and Amazon. And what happened to the Sahara Desert, which was depicted in rock art as an area of lakes, rivers, boats and animals?

From lakes and grasslands with hippos and giraffes to a vast desert, the sudden geographic transformation of North Africa 5,000 years ago is one of the most dramatic climate changes on the planet. The transformation took place almost simultaneously throughout the northern part of the continent.

Scientists write that the Sahara turned into a desert almost instantly!

Transformation of North Africa 5,000 years ago is one of the most dramatic climate changes on the planet.

If the Sahara became a huge desert a few thousand years ago or so, what event contributed to this - did it turn the substance into sand or led to the release of huge quantities of sand into the area?

A team of researchers tracked the region's wet and dry periods over the past 30,000 years by analyzing sediment samples off the coast of Africa. Such deposits consist, in part, of dust blown from the continent over thousands of years: the more dust accumulated over a certain period, the drier the continent was.

Based on measurements taken, the researchers found that the Sahara emitted five times less dust during the African wet period than it does today. Their results, indicating much greater climate change in Africa than previously thought, will be published in the journal Earth and Planetary Science Letters.

Theories of the origin and formation of sand

The origin and formation of most of the sand on Earth and in the Sahara comes down to:
Natural - due to erosion or influenced by the atmosphere
Extraterrestrial - massive dumping of sand during planetary interactions (scenario described in Velikovsky's book Worlds in Collision)
Extraterrestrial - Earth's capture of debris/sand from the Solar System after planetary disasters such as satellite capture.
Creation/transformation of matter by phenomena of the Electric Universe such as cometary and planetary discharges in the Solar System
Formation of the Electric Universe by local geological phenomena?
Introduced from the bowels of the planet (mud storms, etc.)
Still being formed in real time by Electrical Geology phenomena in the Electric Universe?

And here's another interesting guess:

Theory of the origin of sand in the context of the Electric Universe

The theory states that Mars has been involved in hundreds of catastrophic close encounters with Earth in historical times.

Immanuel Velikovsky with his theory and book Worlds in Collision: Planets, satellites and comets are electrically discharged and explode.

Velikovsky's ideas about disasters and geology, described in the book Earth in Revolution.

When there is a highly charged object such as a comet heading towards the earth, then before it hits there will be an electrical discharge between the two bodies, the magnitude of which will be sufficient to destroy the incoming object - thus, everything will end with a hail of sand and the like.

During the famous Chicago fire the entire US territory was illuminated by strange lights, accompanied by falling sand and similar phenomena. This happened during the disappearance comet Biela. (1871)

Is it possible that the Earth is covered in debris from recent space disasters? Could debris such as large boulders, rocks, stones, dust and sand that are believed to originate on Earth actually be extraterrestrial in origin?

Countless tons of rocks bombard the Earth's atmosphere, fragmenting and breaking down into tiny particles of sand. Having fallen to the Earth, they cover vast areas that were once green and fertile lands, turning them into the deserts that we see today.

This and much more suggests that the catastrophic events of the past had a real basis, but were transformed into a kind of symbolic clues. It is also important that our present time, quite possibly, may soon also become only a symbolic hint for the future generation of people.

The Earth is like a magnet, attracting everything that flies past, in the form of comets, fireballs, asteroids and... (Well, yes, it’s possible that the version is passable) Over millions of years, it would be possible to collect such an amount of sand.

So what do we know?

5000 years ago everything was different in the Sahara. There was greenery everywhere.. Animals that needed grass, and... Carved on stone (see picture) There is also a sailboat. That is, there was water on which boats floated.

An event of grand scale took place on Earth about 5,000 years ago. It's hard to imagine what exactly it was. The period is not short... One can only guess..(build different versions) from space to..

There is no water, the sailboats have crumbled into dust, the animals have gone closer to water and food. And only sand in incredible quantities quietly keeps the secret...

The ancient Greek philosopher-mathematician Pythagoras once puzzled his students by asking them the question of how many grains of sand there are on Earth. In one of the tales told by Scheherazade to King Shahryar during 1001 nights, it is said that “the armies of the kings were countless, like grains of sand in the desert.” It is difficult to calculate how many grains of sand there are on Earth or even in the desert. But you can quite easily determine the approximate number of them in one cubic meter of sand. Having calculated, we find that in such a volume the number of grains of sand is determined by the astronomical figures of 1.5-2 billion pieces.

Where did countless grains of sand come from on Earth? To answer this question, let's take a closer look at this interesting breed.

If we fly in an airplane over the Kyzylkum and Karakum deserts, we will see an immense sand sea (Fig. 5). Its entire surface is covered with mighty waves, as if frozen “and petrified in the midst of an unprecedented storm that engulfed colossal spaces.” In the deserts of our country, sand seas occupy an area exceeding 56 million hectares.

Looking at sand through a magnifying glass, you can see thousands of sand grains of different sizes and shapes. Some of them have a round shape, others have irregular outlines.

How are grains of sand formed?

Geologists have found that their origin has a long and complex history. The ancestors of sand are massive rocks: granite, gneiss, sandstone.

The story of grains of sand does not end here. For large aggregations to form, the grains must become travelers.

Sand is, on the one hand, such a familiar and simple material to everyone, and on the other hand, it is so mysterious and enigmatic. You look at him and cannot take your eyes off.
I'm into an art called sandart. This is a special type of drawing-animation, but instead of paints they use dry sand. During classes, I began to wonder why he was like that.
If you touch, you calm down. You want to look at it, run your fingers through its small grains. Watch how it pours from hand to hand. Sand is so pleasant to the touch.
In my research work, I decided to expand my knowledge about the material with which I work. The work is relevant and can be applied at school as additional material for classes.

Purpose of the study: Study sand: its origin, types, uses. Conduct an experiment on creating sand at home.

Tasks:
1. Find out what sand is?
2. Get to know different types of sand
3. Find out where sand is used?

Research hypothesis: If sand is a chemical compound, is it possible to conduct a chemical experiment to make it at home using scrap materials?

Study plan:
1.Familiarize yourself with information about sand
2. Prepare everything necessary for the experiment
3. Conduct an experiment
4.Draw conclusions

What is sand?
Everyone can imagine what sand is. From a scientific point of view, it is still a bulk material of inorganic origin, consisting of many small grains of sand or fractions, sedimentary rock, as well as artificial material consisting of rock grains
Sand is made from small particles of minerals that are part of rocks, so various minerals can be found in sand. Quartz (a substance - silicon dioxide or SiO 2) is mainly found in sand, since it is durable and there is a lot of it in nature.
Sometimes sand is 99% quartz. Other minerals in the sand include feldspar, calcite, mica, iron ore, as well as small quantities of garnet, tourmaline and topaz.

1.1. How and from what was sand formed?
Sand is what is left of rocks, boulders, and ordinary stones. Time, wind, rain, sun and time again destroyed mountains, crumbled rocks, crushed boulders, crushed stones, turning them into billions of billions of grains of sand ranging in size from 0.05 mm to 2.5 mm, making sand out of them. Sand is formed where rocks are subject to destruction. One of the main places where sand formation occurs is the seashore.
The second most common form of sand is calcium carbonate, such as aragonite, which was created over the last one and a half billion years by various life forms such as corals and shellfish.
What about sand in deserts? Sand from the shore is carried by the wind inland. Sometimes so much sand is moved that an entire forest can be covered by sand dunes. In some cases, desert sand is formed as a result of the destruction of mountain ranges. In some cases, on the site of the desert there was once a sea, which, having retreated thousands of years ago, left sand here.

Classification by characteristics
Sands are classified according to the following criteria:

Density;

Origin and type;

Grain composition;

Content of dust and clay particles,
including clay in lumps;

Content of organic impurities;

The nature of the grain shape;

Content of harmful impurities and compounds;

Strength.

River and sea sands have rounded grains. Mountain sands are acute-angled grains contaminated with harmful impurities.

Types of sand
Natural sand
river sand- This is sand that is mined from the bottom of rivers and is characterized by a high degree of purification. It is a homogeneous material with the absence of foreign inclusions, clay impurities and pebbles. It is purified naturally - by the flow of water.
The main advantage of river sand is that it is sand, and not a sand mixture containing clay, earth, or stone particles. Thanks to long-term natural exposure, sand grains have a smooth oval surface and a size of approximately 1.5-2.2 mm.
River sand is a fairly high-quality, but at the same time quite expensive building material. River sand is extracted using special equipment - dredgers. This does not harm the environment at all, but on the contrary helps to clean river beds. The coarsest river sand is mined at the mouths of dry rivers.
The color palette of mined sand is quite diverse, from dark gray to bright yellow. The reserves of this building material in nature are practically inexhaustible.
Everyone knows that in some regions of the Russian Federation
river sand is a source of gold mining

Sea sand- this is sand that contains (in comparison with other types of sand) the smallest amount of foreign impurities. The purity of sea sand is determined by the place of its extraction, as well as the use of a two-stage cleaning system to remove foreign inclusions. The first stage of sand cleaning takes place directly at the site of its extraction, and the second stage - within special production sites. Considering the high quality of sea sand, it, without exaggeration, can be used in any construction work.

Quarry sand is a natural material mined in open pits. This sand has a fairly high content of clay, dust and other impurities. Quarry sand is cheaper than river sand, which makes it widely used. Depending on the cleaning method, it is divided into seeded and washed quarry sand.
Quarry washed sand- This is sand extracted from a quarry by washing with a large amount of water, as a result of which clay and dust particles are washed out of it. Sand can include various types of impurities, such as stones, earth, clay. Mining is carried out using excavators in large open pits. Quarry sand is usually divided according to the size of its constituent grains. It can be fine-grained (particles up to two millimeters in size); medium-grained (particles ranging in size from two to three millimeters); coarse-grained (particles ranging in size from two to five millimeters). Quarry sand has a coarser structure compared to river sand.
Quarry seeded sand- This is sifted sand extracted from a quarry, cleared of stones and large fractions.

Construction sand
Unlike natural varieties, artificial sands are produced using specialized equipment through mechanical or chemical action on rocks.
In turn, artificial sands are divided into subtypes of sedimentary and volcanic origin.
Construction sand can be used as a universal base for the production of a variety of building materials and cement mortars. Such a wide scope of application is primarily due to one of the specific qualities of this material: porosity.
Artificial sand has many advantages compared to natural sand, but it also has its disadvantages, namely: in addition to the relatively high price, artificially produced sand may have higher radioactivity.
Perlite sands- are produced through heat treatment from crushed glasses of volcanic origin, called perlites and obsidians. They are white or light gray in color. Used in the manufacture of insulation elements.
Quartz. Sands of this type are also commonly called “white” because of their characteristic milky white hue. However, the more common varieties of quartz sand are yellowish quartz, which contains a certain amount of clay impurities.
In comparison with sands of natural origin, this material is advantageously distinguished by its homogeneity, high intergranular porosity, and therefore dirt holding capacity.
Quartz sand is mined in quarries. Quartz sand is used to create sand-lime bricks and silicate concrete, fillers for polyurethane and epoxy coatings, which gives them strength and high wear resistance.
Due to its versatility and high quality, this type of sand is widely used in various industries, including water treatment systems, glass, porcelain, oil and gas industries, etc.
Marble. It is one of the rarest species. Used to make ceramic tiles, mosaics, and tiles.

Application of sand
Widely used in building materials, for the reclamation of construction sites, for sandblasting, in the construction of roads, embankments, in residential construction for backfilling, in the improvement of courtyard areas, in the production of mortar for masonry, plastering and foundation work, used for concrete production . In the production of reinforced concrete products, high-strength concrete, as well as in the production of paving slabs and curbs.
Fine construction sand is used to prepare solutions.
Sand is also used in glass production, but only one type is quartz sand. It consists almost entirely of silicon dioxide (quartz mineral). The purity and uniformity of sand make it possible to use it in the glass industry, where the absence of the slightest impurities is important.
Less pure quartz sand is used in plastering (internal and external) finishing works. Using it in the production of concrete and brick allows you to give the resulting product the desired shade.
Construction river sand is quite widely used in various decorative (mixed with various dyes to obtain special structural coatings) and finishing works of the finished premises. It also acts as a component of asphalt concrete mixtures, which are used in the construction and laying of roads (including for the construction of airfields), as well as in water filtration and purification processes.
Quartz sand is used for the manufacture of welding materials for special and general purposes.
Agriculture: Sandy soils are ideal for crops such as watermelon, peaches, nuts, and their excellent characteristics make them suitable for intensive dairy farming.
Aquariums: It is also an absolute must for saltwater reef aquariums, which emulates the environment and consists mainly of aragonite corals and shellfish. Sand is non-toxic and completely harmless to aquarium animals and plants.
Artificial reefs: sand can serve as the basis for new ones
reefs.Beaches: Governments move sand to beaches where
tides, eddies or deliberate changes to the shoreline erode the original sand.
Sand is Sand Castles: Forming sand into castles or
other miniature buildings are popular in cities and on the beach.
Sand Animation: Animation Filmmakers Use
sand with front or back illuminated glass. That's how I do it too.

Practical part
We were faced with a task: is it possible to make silicon dioxide at home?
To conduct the experiment I will need:

silicate glue;

vinegar 70%;

container 2 pieces or molds;

syringe;

apron, gloves.

It is necessary to observe safety precautions - vinegar is an acid. We conduct the experiment in a room with open windows, because the vinegar smells strong. You cannot bend over, smell or try anything. We put on protective equipment.
I take silicate glue. Carefully pour about 1/3 into the container.
Then I take the vinegar and pour it into another container. About the same 1/3.
I use a syringe to remove vinegar from the container. I take about 10 ml.
Very carefully pour vinegar into the glue.
A reaction occurs. The glue turns into a gel and hardens. Using a stick, thoroughly mix the glue and vinegar.
I got Silicon Dioxide (SiO2) - a substance consisting of colorless crystals with high strength, hardness and refractoriness.
In nature, silicon dioxide is quite widespread: crystalline silicon oxide is represented by minerals such as jasper, agate, rock crystal, quartz, chalcedony, amethyst, morion, and topaz.
You can mix vinegar, glue and food coloring of any color. The result is colored silicon dioxide.

Sand is hard rock that has been broken down into small pieces by water and wind over millions of years. Basically, such pieces are small, no more than a few millimeters in size, grains of quartz - the most common mineral on Earth, consisting of silicon dioxide molecules. Silicon dioxide is not only found in the form of quartz on sandy beaches. You can easily find it in a package of chips or crackers. It is used there as a leavening agent - this means that it prevents food particles from sticking together. But this “sand,” which you can eat along with crackers, is much finer than usual, and it does not harm the body.

Let's see what sand can consist of, besides quartz.

The transparent crystals here are grains of quartz, but besides them we also see grains of other minerals. The fact is that sands are actually very different, depending on their origin. Volcanic sands, for example, may contain pieces of red minerals, causing the beach to appear red. There are several beaches in the world where the green mineral chrysolite is found in the sand. That's why the beaches there are green. And in some countries there are black sands containing many heavy minerals such as hematite or magnetite.

But the most interesting thing is that, in addition to minerals, sand, especially sea sand, often contains fossilized remains or shells of simple animals and plants that lived millions of years ago.

These shells are usually made of calcium carbonate - that is, chalk. This is the same chalk that is used in the classroom to write on the blackboard, or on the street to draw on the asphalt.

European scientists initially became acquainted with sands far from deserts - on the banks of rivers, moraines and oceans. The sands brought by rivers are exposed from under the water only during low-water periods and, in the climatic conditions of Europe, are almost never blown over. Ancient river sands in European countries are distributed in small strips, overgrown with forests, and therefore river sands in Europe do not cause much harm and are not dangerous to anyone.

The sands on the shores of the oceans are a different matter. Storm waves and tidal waves throw more and more masses of sand onto the shore each time. The winds blowing over the ocean easily pick up the dried sand and carry it deep into the continent. It is not easy for vegetation to establish itself on such constantly blowing sand. And then some more goats will come from the village and attack, trample, or even uproot the fragile shoots. And it happened more than once that fishermen’s villages, and even large villages and towns, found themselves buried under sand dunes on the coast of Europe. Centuries passed, and only the top of the high spire of the old Gothic cathedral, sticking out of the sands, reminded people of the destruction of the village that had once occurred.

Almost the entire western Atlantic coast of France has been covered with sand for centuries. Many areas of the northern coast of East Germany and the Riga seaside also suffered from them. The raging Atlantic, North and Baltic seas and the advancing sands they generated were the most formidable picture of nature familiar to the inhabitants and scientists of Europe.

And naturally, when the Europeans found themselves in the deserts and became acquainted with their huge sand massifs, like the sea, they involuntarily believed that the desert sands were the brainchild of the sea. This is how the “original sin” appeared in the study of deserts. The usual explanation was applied to the sands of the Sahara, which supposedly were the bottom of a recent ocean, and to the sands of Central Asia, which were supposedly covered in ancient times by the inland Hanhai Sea.

Well, what can we say about our deserts, where the Caspian Sea actually flooded spaces that rose 77 meters above its current level?

And, however, it is Russian researchers who have the honor of overthrowing these incorrect views, according to which sea waves were considered the only powerful creator of sand on earth.

In this regard, many of our researchers of the 19th century were on the right track, when they first began to study various regions of Central and Central Asia. Among them, first of all, we must name Ivan Vasilyevich Mushketov, a pioneer in the geological study of Central Asia, and his student Vladimir Afanasyevich Obruchev, who made many difficult and lengthy journeys throughout Central and especially Central Asia. These two researchers, combining geologists and geographers, showed that, along with truly sea sands, sands of other origins are widely developed in deserts.

I.V. Mushketov believed that, in addition to sea and river sands, in many desert areas, including Kyzyl-Kum, sands are formed during the destruction of various rocks in a sharply continental desert climate. One of the merits of V. A. Obruchev was the substantiation by a number of facts of the position that the sands of another empty Central Asia - Kara-Kum - were formed due to sediments of the ancient Amu Darya, which previously flowed from the area of the city of Chardzhou directly to the west to the Caspian Sea.

He also proved that in the deserts of eastern Central Asia, in Ordos and Ala Shan, the main creator of sand is the destructive forces of the atmosphere.

The arguments of these scientists were logical and convincing, but they had too few facts to fully resolve the questions of the origin of each mass of sand in the deserts.

During the Soviet period, much more research was devoted to a comprehensive study of sands. As a result, it was possible to establish the sources and accumulation paths of a wide variety of sand massifs, although it was not always easy to reconstruct their biography.

In western Turkmenistan alone we counted twenty-five sand groups of different origins. Some of them were formed due to the destruction of ancient rocks of different age and composition. This group of sands is the most diverse, although it occupies a relatively small area. Other sands turned out to be brought by the Syr Darya to the area of the modern Khiva oasis. Still other sands were brought by the Amu Darya and deposited on the plains, now located at a distance of 300 - 500 kilometers from the river. The fourth sands were carried by the Amu Darya into the sea, the fifth, very special sands, accumulated in the sea due to shells of sea mollusks crushed by waves. The sixth sands were formed in the now waterless, but formerly lacustrine Sarykamysh depression. They contain a mass of calcareous and flint skeletons of microorganisms.

Sea of sand. From the northern Aral Sea region to the south, along the eastern shores of the Aral Sea, through the entire Kyzyl-Kum desert and further, through the expanses of the Kara-Kum to Afghanistan and the foothills of the Hindu Kush, and from east to west from the foothills of the Tien Shan to the shores and islands of the Caspian Sea stretches a huge, covered waves of the sea, above which only isolated islands rise. But this sea is not blue, its waves do not splash, and it is not filled with water. The sea shimmers in red, yellow, gray, and whitish tones.

Its waves, in many places immeasurably higher than the breakers and swells of the ocean, are motionless, as if frozen and petrified in the midst of an unprecedented storm that covered colossal spaces.

Where did these huge accumulations of sand come from and what created their motionless waves? Soviet scientists have studied the sands well enough to now be able to answer these questions definitely.

In the Aral Kara-Kums, in the Big and Small Barsuki sands and on the eastern shores of the Aral, the sands have a dull white color. Each grain is rounded and polished, like the smallest grain. These sands consist almost exclusively of quartz alone - the most stable of minerals - and a small admixture of smaller black grains of ore minerals, mainly magnetic iron ore. These are old sands. Their life path was long. It is difficult to find the remains of their ancestors now. Their lineage dates back to the destruction of some ancient granite ridges, the remains of which are now preserved on the surface of the earth only in the form of the Mugodzhar Mountains. But since then, these sands have been redeposited many times by rivers and seas. This was the case in the Permian, and in the Jurassic, and in the Lower and Upper Cretaceous. The sands were last rewashed, sorted and redeposited at the beginning of the Tertiary period. After this, some layers turned out to be so tightly welded with silicic acid solutions that the grains merged with cement, forming a hard, oily quartzite, pure as sugar. But even this strongest stone is affected by the desert. Loose layers of sand are blown away, hard stones are destroyed, and again the sands are redeposited, this time not by sea or river water, but by the wind.

Our research has shown that during this last “air travel” of sands, which began in late Grecian times and continued throughout the Quaternary period, they were transported by the wind from the northern Aral Sea region, along the eastern shores of the Aral Sea up to the shores of the Amu Darya, and possibly and further to the south, that is, approximately 500 - 800 kilometers.

How did Red Sands happen? It is not for nothing that the Kazakhs and Karakalpaks call their largest sandy desert Kyzyl-Kum, that is, Red Sands. Its sands in many areas actually have a bright orange, reddish-red, or even brick-red color. Where did these layers of colored sand come from? From the destroyed mountains!

The ancient mountains of the Central Kyzyl-Kum are now low, rising 600 - 800 meters above sea level. Millions of years ago they were much higher. But for the same amount of time they are exposed to the destructive forces of wind, hot sun, night cold and water. Remnant hills, like islands, rise above the surface of the Kyzyl-Kum. They are surrounded, like trains, by strips of gently sloping gravelly alluvial deposits, and then sandy plains stretch beyond.

In the Middle Ages of the earth's history, both the Mesozoic and the beginning of the Tertiary period, the climate here was subtropical and red earth soils were deposited on the mountain slopes. The destruction of the remnants of these soils, or, as geologists say, “ancient weathering crusts,” is what colors the Kyzyl-Kum sands in red tones. But the sands of this desert do not have the same color everywhere, since their origin is different in different areas. In places where ancient sea sands were subjected to winding, the sands of these plains are light yellow. In other areas, these sands are yellowish-grayish - these are ancient sediments of the Syr Darya. Take a look at the diagram on page 64, and you will see that we were able to trace these sediments both in the southern, central and western parts of the desert. In the south of Kyzyl-Kum, their sands are dark gray and they were brought by the Zeravshan River, and in the west of this desert the sands are bluish-gray and contain a lot of mica sparkles - they were brought here by the Amu Darya in one of the standards of its wanderings. Thus, the history of the Kyzyl-Kum is far from simple, and the biography of their sands is perhaps more complex and diverse than most other deserts in the world.

How were Black Sands formed? . The southernmost desert of the USSR is the Kara-Kum. This name - Black Sands - was given to them because they are heavily overgrown with dark saxaul bushes and the horizon in many places darkens like the edge of a forest. In addition, the songs here are dark - grayish.

In those interridge depressions where the wind reveals previously fresh sands, their color is steel-gray, sometimes bluish-gray. These are the youngest sands - baby sands in the history of our planet, and their composition is very diverse. 42 different minerals can be counted in them under a microscope. Here, in the form of small grains, there are also garnets and tourmalines, familiar to many from necklaces and rings. Large plates of shiny mica, grains of quartz, pink, greenish and cream grains of feldspars, black-green grains of hornblende sand are visible to the eye. These grains are so fresh, as if they had just ground and washed the granite. But where the wind has managed to blow away the sands, their color changes, taking on a grayish-yellow color. And at the same time, the shape of the grains of sand slowly, gradually begins to change: from the angular shape characteristic of young river sands, it increasingly takes on the rounded shape of the so-called “aeolian” sands blown by the wind.

The composition of the Kara-Kum sands, the shape of their grains, the good preservation of low-stable minerals, their gray color, the conditions of occurrence and the nature of the layering indisputably indicate their river origin. But the question is, what kind of river can we be talking about if the Kara-Kums begin in the south from the very foot of the Kopet-Dag, and the nearest large river - the Amu Darya - flows at a distance of 500 kilometers? And where can such a quantity of sand come from in the river to cover a huge desert - more than 1300 kilometers long and 500 kilometers across?

Every time I visited different areas of the deserts of Central Asia, I took samples of their sands and submitted them for microscopic analysis. These studies showed that the Kara-Kums were indeed deposited by the Amu Darya, and partly, in its southern part, by the Tedzhen and Murghab rivers (see map on page 69). The composition of the sands of these rivers, carried directly from the mountains, turned out to be exactly the same. as well as in the desert areas they created, lying a hundred kilometers from the current channels of the Murgab and Tedjen and 500-700 kilometers from the modern Amu Darya. But, one wonders, where does such a huge amount of sand come from in mountain rivers? To get an answer to this question, I had to get to the area where the Amu Darya originated - in the highlands of the Pamirs.

Mountain sand tract. In 1948, I had the opportunity to visit the Pamirs. And here, among mountain ranges and inaccessible rocky cliffs, almost a thousand kilometers from sandy deserts, I came across a small tract, lost in the mountains, which turned out to be a genuine natural laboratory for the formation of sands.

The Nagara-Kum tract, which we called by consonance “The Highland Sands Tract,” is located at the junction of three intersecting valleys, at an altitude of 4-4.5 thousand meters above sea level. One of the valleys stretches in the meridional direction, and the others in the latitudinal direction. These valleys are not particularly long, their width does not exceed 1 - 1.5 kilometers, but they are deep. The flat, undivided bottom of the valleys is not indented by traces of water flows or ancient channels. And that is why, perhaps, the contrast between the smooth and flat bottoms of the valleys and the steep dissected rocky, bare slopes of the mountains is so striking. It seems as if someone has cut deep and wide corridors in the mountains.

Everything indicated that these valleys, geologically relatively recently, were the bed of powerful glaciers sliding down from the snow-capped mountains. And the smoothed, unweathered rocks of the slopes of the amphitheater, located in the eastern part of the latitudinal valley, indicated that they had recently been buried under a layer of firn snow.

A number of data suggested that when the glaciers disappeared, lakes took over the valleys. However, now in this cold mountain kingdom there is too little precipitation, so little that even in winter the snow does not cover the area completely. Therefore, over time, the lakes also disappeared.

In the neighboring valleys, powerful ice dams do not melt even in summer. Here, around the tract, the peaks, higher than Kazbek and Mont Blanc, blacken against the background of a clear blue sky - they are almost not covered with snow in the summer, but sometimes there is little of it in the winter.

We were in Harapa-Kuma during the warmest time of the year - mid-July. During the day, when there was no wind, the sun burned so hard that the skin on our faces (and we had been in Kyzyl-Kum for a month before) was cracking from burns. During the day in the sun it was so hot that I had to take off my sheepskin coat, jacket, and sometimes even my shirt. But this was extremely rarefied air in the highlands, and as soon as the sun set and its last rays disappeared behind the mountain peaks, it instantly became cold. Temperatures dropped sharply and were often well below freezing throughout the night.

The significant altitude of the area, dry thin air and cloudless skies lead to extremely sharp temperature changes.

The transparent, rarefied air of the highlands almost does not prevent the sun's rays from heating both the earth and the rocks during the day. At night, intense radiation is emitted from the earth, heated during the day, back into the atmosphere. However, the rarefied air itself hardly heats up. It is equally transparent to both sunlight and night rays. It heats up so little that it was enough for a cloud to pass during the day or the wind to blow, and it immediately became cold. This sharp change in temperature is perhaps the most characteristic and, in any case, the most active climatic factor in the high mountain regions.

It is also important that at these altitudes there are night frosts almost every day in summer, and if the stone does not crack due to rapid cooling, then water will finish the job. It seeps into the smallest cracks and, freezing, tears them apart and expands more and more.

The rocks of the eastern slopes of the tract are composed of rounded blocks of coarse-grained gray granite porphyries with well-cut greenish feldspar crystals up to 4-5 centimeters long. The mountain slopes formed by these rocks appear at first glance to be a grandiose accumulation of large moraine boulders, a heap of perfectly round glacial boulders rising above the plain. And only the contrast between the steep piles and the table-smooth valley bottoms, where there is not a single such boulder, makes us more cautious about the assumption that these are glacial boulders.

Having carefully looked at the slopes of the tract, we discovered an amazing thing. Many boulders of gray granite porphyry turned out to be dissected by white stripes of veins consisting of only feldspars - the so-called aplites. It would seem that aplite veins should be located in the boulders brought by the glacier in the most random manner. But why is it absolutely clear that the vein in one boulder is, as it were, a continuation of the vein in another boulder? Why, despite the accumulation of boulders, do aplite veins maintain a single direction and structure along the entire slope, although they intersect tens and hundreds of granite blocks?

After all, no one would be able to diligently lay all these boulders in such an order, strictly making sure not to change the direction of the veins. If a glacier had brought them in, it would certainly have piled up the boulders in the most chaotic manner, and the aplite veins could not have had the same direction in neighboring boulders.

I examined the large round blocks for a long time until I was convinced that many of them were only half-separated from the mountain, like a lump on the lid of a porcelain teapot. This means that these are by no means glacial boulders, but the result of destruction in place of bedrock, from which, over the course of many centuries, nature produced these blocks, or, as geologists call them, spherical weathering units under the influence of sudden changes in temperature. This was also evidenced by the fact that many of the balls had shells peeling off from them, which is typical for processes of mechanical destruction - peeling of rocks.

Granite round timbers, the most varied in size, from 20-30 centimeters to 2-3 meters in diameter, were half buried under a layer of debris and sand formed during the peeling of granite, crumbling from them. These decomposition products turned out to be mineralogically so fresh that the sand grains retained their original appearance; They had not yet been touched by either chemical decomposition or abrasion, and sharply cut crystals of feldspars - a mineral that is chemically the least stable - lay here in the sand, shining in the sun with completely fresh surfaces of the faces.

Many of these blocks crumbled into grains at the slightest touch. The entire area provided clear evidence of the strength, power and inevitability of the processes of rock destruction that change and shape the earth's surface over thousands of years.

“Hard as granite” - who doesn’t know this comparison! But under the influence of sunlight, night cold, freezing of water in cracks and wind, this hard granite, which has become synonymous with strength, crumbles into sand under a light pressure of the fingers.

In high-mountain regions, the process of temperature destruction proceeds so quickly that the chemical decomposition of minerals does not have time to affect the decay products at all. The destruction is happening so intensely that almost half of the mountain slopes are already covered with scree and sand.

Strong winds that often blow here pick up the smallest products of granite decay and blow out all the dust and sand from them. Dust is carried by air flow far beyond the boundaries of the tract; sand, heavier than dust, is dumped here, in all those places where the wind force decreases due to obstacles encountered.

Over time, a sand bank formed along the entire meridional valley for 13 kilometers. Its width ranges from 300 meters to one and a half kilometers. In some places it is quite flat, smoothed, covered with herbaceous vegetation. To the north, at the intersection of valleys, where the sand is open to latitudinal winds blowing in opposite directions, the shaft is completely bare and the sand is collected in several dune chains parallel to each other.

These chains are high, up to 14 meters, their slopes are steep, the ridges constantly change their shape, obeying the blowing wind, and the wind blows from the east, then from the west.

Bare, flowing, high and steeply upturned sands, the burning sun and the “smoking” ridges of dunes - all this involuntarily transported us to the hot deserts of Asia.

But the mountain sand tract lies in the kingdom of permafrost. Around the dunes, everywhere you look, are the tops of the ridges, covered with eternal snow and sparkling ice. And in the valleys lying a little lower, there were huge white patches of thick ice, formed from the freezing of spring waters in winter.

The most powerful accumulation of sand in the tract is located at the southern intersection of the valleys. The winds blow the strongest here.

Reflecting in all directions from the surrounding steep slopes, the winds experience powerful turbulence. The relief of the sands therefore turns out to be the most complex and most upheavy. The dune chains either scatter in different directions, or merge with each other, forming huge nodes of pyramidal uplifts, rising tens of meters above the depressions.

The mass of these clean, wind-blown sands covers an area of only 14.5 square kilometers in the tract, but nevertheless the thickness of these sand accumulations is quite large, about one and a half hundred meters.

Having experienced these turbulences, the wind rushes further to the east. Rising to the nearby pass, air currents lift the sand and pull it along the slope. The sand stretches in the direction of the prevailing winds in a strip tapering towards the east. This strip stretches up almost 500 meters and goes from the main massif of sands not along the lowest and widest main valley, but in a straight line to the pass, while climbing a fairly steep slope.

So, high in the mountains of the “Roof of the World” and “Foot of the Sun” - the snow-capped Pamirs - there was a corner of the sandy desert! A corner in which nature carries out the entire process of sand formation and development from beginning to end! First, the emergence of igneous rocks to the surface, their destruction by temperature fluctuations, the formation of scree, its crushing into sand grains and, finally, powerful piles of wind-blown sand. And not only winnowed, but also raised by him into dune pyramids the height of a twenty-story building, assembled into a sandy relief typical of deserts!

All these processes took place over a relatively short period of time on a geological scale. However, the strength and power of these processes are such that everything that takes millennia in the deserts was accomplished literally ten times faster in the mountain sands.

It is important, however, that this destruction of rocks and their transformation into sand is not an exceptional phenomenon, but, on the contrary, is very typical for all dry high-mountain regions. On the greatest highland in the world - Tibet - there are many such sandy tracts. In the Pamirs and Tien Shan, sands less often accumulate into massifs due to relief conditions, but they are formed there constantly and continuously for several million years. Lake Kara-Kul, located in the Pamirs in the permafrost region, is bordered on the east by continuous sand. And almost every grain of sand in these highlands, formed under the influence of sudden changes in temperature, melting and freezing of water, soon becomes the property of a scree, and then a mountain stream. This is why rivers in the highlands bring gigantic amounts of sand to the foothill plains. This is where the Amu Darya gets up to 8 kilograms of sand during floods, and on average it carries 4 kilograms of sand in every cubic meter of water. But there is a lot of water in it, and in just one year it brings a quarter of a cubic kilometer of sediment to the shores of the Aral Sea. Is this too much? It turned out that if we take the duration of the Quaternary period to be 450 thousand years, consider that during this period the Amu Darya carried out the same amount of sand, and mentally distribute it in an even layer over all those areas where the mighty Amu wandered during this time, then the average thickness only its Quaternary sediments would be equal to three quarters of a kilometer. But sand was carried out by the river before, in the second half of the Tertiary period. That is why it is not surprising that in its former mouths, in southwestern Turkmenistan, oil wells penetrate this layer of sand and clay to a depth of 3.5 kilometers.

Now it is clear to us that most of the submontane sandy deserts of Asia are the creation of the highlands. These are the Kara-Kums, which are a consequence of the destruction of the high-mountain Pamirs. These are many areas of Kyzyl-Kum, formed as a result of the destruction of the Tien Shan. These are the sands of the Balkhash region brought from the Tien Shan by the Ili River. This is the greatest sandy desert in the world, Taklamakan, the sands of which were brought by rivers from the Himalayas, Pamirs, Tien Shan and Tibet. This is the great Indian Thar Desert, created by the sediments of the Indus River flowing from the Hindu Kush.

Sharp temperature changes in deserts and highlands destroy rocks and create sand. Above are flaky sandstone layers in Western Turkmenistan. Below are dune sands in the Nagara-Kum tract in the Pamirs, formed from the destruction of granites. (Photo by the author and G.V. Arkadiev.)

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