Research project "sand, its properties, use and production at home." Sandy layers of the Moscow region and the sands of the tundra Where does so much sand come from in the Sahara Desert?

Sand is a material that consists of loose stone grains with a grain diameter of 1/16 mm to 2 mm. If the diameter is more than 2 mm, it is classified as gravel, and if less than 1/16, then as clay or silt. Sand is mainly created by destruction rocks, which over time accumulate together to form grains of sand.

Sand weathering process

The most common method of sand formation is weathering. This is the process of transforming rocks under the influence of factors such as water, carbon dioxide, oxygen, temperature fluctuations in winter and summer period. Most often, granite is destroyed in this way. The composition of granite is quartz crystals, feldspar, and various minerals. Feldspar, when in contact with water, disintegrates faster than quartz, which allows granite to crumble into fragments.

Sand denudation process

As rocks collapse, they move from higher elevations downward under the influence of wind, water, and gravity. This process is called denudation.

Under the influence of weathering, denudation and accumulation processes minerals Over a long period of time, one can observe the leveling of the land relief.

Sand fragmentation process

Fragmentation is the process of crushing something into many small fragments, in our example it is granite. When the crushing process occurs quickly, the granite is destroyed even before the feldspar is destroyed. Thus, the resulting sand is dominated by feldspar. If the crushing process occurs slowly, then the content of feldspar in the sand decreases accordingly. The process of rock fragmentation is influenced by the flow of water, which enhances fragmentation. As a result, we have sands with low feldspar content on steep slopes.

Sand grain shape

The shape of the sand grains starts out angular and becomes more rounded as they are polished by abrasion during transport by wind or water. Quartz sand grains are the most resistant to wear. Even a long stay near the water, where it washes it, is not enough to thoroughly roll the angular quartz grain. Recycling time is on the order of 200 million years, so a quartz grain that first eroded from granite 2.4 billion years ago may have gone through 10 to 12 cycles of burial and re-erosion to reach its current state. Thus, the degree of roundness of an individual quartz grain is an indirect indicator of its antiquity. Feldspar grains can also be rounded, but not as well, so sand that has been moved several times is mostly quartz.

The influence of the ocean and wind on the process of sand formation

Sand can be formed not only by weathering, but also by explosive volcanism, as well as as a result of the impact of waves on coastal rocks. As a result of the influence of the ocean, the sharp corners of the rocks are polished and over time they become crushed. This way we get the sea sand we are used to. During a storm in the cold season, water that gets into the cracks of the rocks becomes ice, which leads to splitting. Thus, over time, sand is also obtained. Nothing would have happened without the intervention of the wind. The wind wears grains of sand on the rocks and scatters them.

Application area of sand

Sand surrounds us everywhere. It is most used in construction. By combining it with water and cement we get a concrete solution. Sand is added to dry building mixtures in the manufacture of artificial stone and tiles. Sand has even found use in alternative medicine for the prevention of radiculitis and problems with musculoskeletal system. No children's playground is complete without a sandbox. Sand is also widely used for making glass; backfilling into sandblasting machines to clean the surface from rust and various types of corrosion; for filling football fields; as soil for an aquarium; .

Details about the origin of quartz sand can be emphasized from the article: A large selection of fractionated quartz sand can be found on our website.

Where did the sand come from in our Shibaevsky quarry? Imagine, although it is very difficult to imagine, you need to try to imagine that many, many millions of years ago there was not a single grain of sand in the world. But there was also no air, no water, no plants, no animals...

Planet Earth was at a very young age (by geological standards), and its main attractions were only mountain ranges and volcanoes that erupted hot streams of lava. It was the rocks that became the “raw material” for the production of sand.

However, this required that our planet acquire oceans, rivers - what is called the hydrosphere, and air - an atmosphere. Only then did the wind and water begin to work. Slowly, over millions of years, they worked on durable granite and other rocks. It’s not for nothing that the saying about the drop that wears away the stone appeared.

Imagine, pieces broke off from the rocks, large fragments turned into small ones, which in turn disintegrated into stones, and those into pebbles. Well, from pebbles to grains of sand, which are already separate indivisible grains of rocks and various minerals.

This happened all over the planet, and on Savina Mountain too, which is why so much sand eventually formed at the foot of Savina Mountain. Mount Nekhoroshka and Savina Mountain have always been adjacent to the Zeleninka River and the Chumlyak River. Water penetrated into the cracks of the mountains and this led to their destruction. Therefore, which breed is there more? Pink sands are composed of feldspar, red sands are made up of the most sand along the banks of these rivers. Sand, fine-grained loose sedimentary rock consisting of at least 50% grains of quartz, feldspars, garnet, tourmaline, topaz rock fragments measuring 0.05-2 mm; contains an admixture of clay particles.

But the Shibaeva sands are green - glauconite, colored in green tones, the intensity of which is determined by the content of the mineral glauconite in the sand.

I also learned that on the planetThere are places where the sands behave unusually. They are singing.For example, Jebel Nakug (Bell Mountain) on the shores of the Red Sea. It has long been covered in legends. Tourists claim that when you climb to its top, the sand seems to groan under your feet. In the depths of this mountain, as the inhabitants of the Sinai Peninsula believe, lies a large monastery. At the appointed hour, its underground bells ring, calling the monks to prayer. And the whole mountain trembles from these powerful sounds.

A similar phenomenon is observed in Chile: in the Copiano valley rises a large sandy hill called El Braiador, which means the Howling One. Several hills in the Californian deserts also “cry” and “moan.” And if you go down from Mount Reg-Ravan, which is not far from Kabul, the capital of Afghanistan, White sand underfoot makes sounds similar to drumming. The phenomenon of singing sands is quite widespread on our planet. The first “singing” hills were described in the written monuments of Ancient China. A huge sandy hill 150 meters high served as an object of worship. On the fifth day of the Moon, the festival of the Dragon, the priests climbed it in order to slide down to the bottom. During this rapid descent, the sand spoke to them in the voice of the Dragon, predicting the future.

There is a beach with singing sand on Lake Baikal. When you walk on it, tourists describe, it makes a creaking sound. And if you rake the sand with your feet, the creaking turns into a jerky howl. It is almost impossible to distinguish an area with singing sand from “mute” sand by eye. A detailed study showed that the grains of singing sand, as a rule, are round or oval, have the same size, are well “polished” by nature and practically do not contain any impurities, even dust. Researchers studying the singing sands of the Hawaiian Islands discovered that each grain of sand there was penetrated by a thin channel, open at one end, so the sound could be made by the wind breaking through the channels? However, there is nothing like this in other singing sands... Hypotheses explaining the nature amazing phenomenon a lot. There is, for example, this: the sound of sand is associated with electrification that occurs when grains of sand rub against each other. However, scientists have not come to a consensus.

Do our Shibaevsky sands sing? I decided to conduct some experiments at home. The Boy picked up stones of different colors on the bank of the river. Then he broke them with a large nail and a hammer, the resulting pieces and grains of sand were of different colors. Thus, I was convinced that the composition of the sand is different because it consists of different rocks and minerals. The color of the sand depends on what type of rock it contains. With another experiment I wanted to make sure which rocks and minerals dissolve better. To do this, I dissolved salt, chalk and sand from the quarry in water. The salt dissolved completely, the chalk did not dissolve well, but after some time it precipitated. But the sand from the quarry did not dissolve at all, but remained at the bottom of the glass unchanged. That is, sand turned out to be the most insoluble and hard, which is why there is so much of it along the banks of rivers and seas.

What can make sounds? To do this, I heated chalk, salt and sand. When the salt and chalk were heated, nothing happened, no sounds were heard. But when the sand was heated strongly, a slight crackling sound was heard and some grains of sand “bounced” and changed their place.This means that our Shibaevsky sands can make sounds!

I tried to understand the question of why the sands sing and came to the following conclusions:

grains of sand are made up of very hard and varied rocks. In hot countries, sand may crackle when heated. And when there is a lot of sand, the sound seems to be singing. And therefore, if warming occurs in the Urals, then our Shibaevsky sands will sing!

The desert in the area of the Lena River basin and its tributary the Vilyuy River has caused many people, at the very least, surprise: where do such volumes of sand come from in this place? Sand is a clear product of erosion, and it is safe to say that it is water erosion. Such a fraction (without large impurities) can be obtained only through water erosion and movement (flaking, precipitation) of masses.

Here's what readers wrote in the comments to the article YAKUT TUKULANS :

l1000 In Belarusian Polesie in the Pripyat River basin there are similar sandy deposits. Moreover, they have a layer of peat layers of varying thickness.

The light areas are sands. It can be seen that these are areas where oil and gas exploration and production of these natural resources is taking place. For this they remove top part soil, turf The sand is exposed. But this has not been done throughout the entire territory. It can be seen that some of the sandy areas are not accessible by any road.
The following views are available:

63° 32" 16.31" N 74° 39" 25.26" E

The river is further south. High sandy shores. Purovsky district, Yamalo-Nenets Autonomous Okrug

Opened turf on the site. 63° 38" 31.17" N 74° 34" 57.89" E

Here is the next location of sand outcrops, a little to the north:

Diameter is approximately 1.3 km. Link https://www.google.com/maps/@63.88379,74.31405,2109m/data=!3m1!1e3

Link
Geologists' sites are visible. And everywhere the light color of sand.

The same picture, light-colored sand under a thin layer of tundra vegetation.

We move northeast:

Drilling site. Sand. Link in place

Komsomolskoye deposit. Here the satellite filmed in higher resolution, you can see the details. Link
Do you think this snow is so white? I thought so too. But we move east, to the river:

It can be seen that the water is not frozen, filming in the warm season.

Sand embankment road

Gubinsky village

High sandy river bank near the town

Several photographs of areas where people damaged a thin layer of vegetation in these places:

64° 34" 6.06" N 76° 40" 45.91" E

62° 19" 50.31" N 76° 43" 17.63" E

63° 7" 35.72" N 77° 54" 31.28" E

The conclusion is that the vast expanses of the Yamalo-Nenets Autonomous Okrug are swamps, rivers and huge layers of sand under a thin layer of vegetation. Ancient sands

Let's move to the Moscow region:

Lyubertsy sand pits

Lyubertsy sand deposit is located 5 km. south of railway station Lyubertsy near the town of Dzerzhinsky near Moscow. This is one of the largest deposits of high-quality quartz sands in Russia. The thickness of the overburden rocks is from 0.3 to 22.6 m, usually 5-8 m. The useful thickness is represented by a reservoir deposit with an area of about 30 square meters. km.

Geological information:

Quartz sands of the Moscow region were formed in the coastal zones of ancient seas and are found mainly in deposits of the Upper Jurassic and Lower Cretaceous. Mainly Upper Jurassic sands of the Lyubertsy and Eganovsky deposits are used. The second largest in the Moscow region is the Chulkovskoye field, located 17-18 km away. south of the city of Lyubertsy. The thickness of the sands at the field reaches 35 m.

If these layers are so ancient, millions of years old, then why is there such a thin layer of black soil and other sediments above them?

In the thickness of the Upper Jurassic quartz sands there are significant interbeds, slabs and pillow-shaped concretions of dense sandstones. Genetically, these are large sheet nodules formed due to the cementation of sand with silica (the cement is predominantly quartz). Some of them are so dense and durable that they correspond rather to the designation “quartzite” than “sandstone”.

Outcrop of quartz sands of the eastern wall of the Dzerzhinsky quarry

Washing sand with a dredger in the near (Dzerzhinsky) quarry of the Lyuberetsky Mining and Processing Plant

Sandstone outcrops in the second, Forest Quarry

Petrified geoconcrete

Can be mistaken for destroyed megaliths or remains

You can see these patterns on stones. Perhaps it was carved when these rocks were still unhardened? Sharp corners and the slots speak about it. If so, then it clearly happened in the recent past. And then what to do with all the geochronological data?

Wild sea buckthorn bushes grow picturesquely on the steep slopes and cliffs above the quarry. For some reason, this shrub really likes to grow in quarries. Somehow this was noticed to me in Krasnoyarsk places.
***

So what catastrophic events or huge marine epochs in the geochronology of the Earth's past provoked these sand accumulations? Official science talks about ancient seas in these territories. But a thin layer of vegetation in the tundra of the Yamal Autonomous Okrug suggests the opposite. There was no accumulation of humus or inorganic soil above the sand. This indicates the very recent presence of sea water or water streams there. Maybe it was the melting glacier and large flows clean water from it flowed south. And was this glacier also quite recently? Who else thinks?

Sources:

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.

Thus, the comparison of Scheherazade 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 under arms globe. 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 (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.

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.

The previous issue talked about the kingdom of sand and sun - deserts. About the Sahara desert, which over three thousand years has bitten off 30% of the territory of the continent of Africa. The reason for the transformation of a flourishing region into a desert is the slow evolution of climate, the beginning of which was the Ice Age.

His Majesty is a man who, perhaps in his pride, considered himself equal to God the Almighty... This is the Sahara Desert. Babe.

"We are all your children, dear Earth." Everyone loved playing in sandboxes. And they wondered where the sand comes from. And even now there are childishly curious people, clearly with creative potential, who ask me the question, where did so much sand come from in the deserts? Why is there so much of it in some places? and in others not at all?

Let me note on my own behalf that all scientists are childishly inquisitive people. They are interested in everything. Einstein said that he could not ignore simple questions that did not interest other people at all.

The Sahara Desert is poor only in vegetation and fauna, but there will be an even bigger fight for it between strong powers - there are quite a lot of mineral resources here. These are, for example, gas, oil, iron and copper ores, uranium, gold and tungsten.

The desert has a fairly diverse topography. Some rocky plateaus and pebble ridges rise to almost 500 meters. In the central part of the Sahara there are mountains - Tibesti with the Emi-Kousi volcano, almost 3.5 thousand meters high, and Ahaggar with Mount Takhat, which has a height of 3 thousand meters.

So where does sand come from in the desert? What is sand made of? Not every adult can answer this question. Looking at grains of sand, you can determine that they consist of different rocks, and therefore have different colors. Sand is a mountain sedimentary rock, which is a loose mixture of particles of various minerals (quartz, calcite, mica, feldspar, etc.) with dimensions in diameter of 0.14 - 5 mm, and formed as a result of weathering of rocks.

There are few deposits that contain almost only quartz sand. But the main part of the sand consists of a mixture of quartz with feldspar, magnetite, mica, garnet, which allows you to give the sand a variety of shades. There are also several deposits on the planet where you can find sand that does not contain quartz. For example, there are white gypsum sands or red coral sands.

Natural sands are usually divided into sea, river and mountain (gully) sands, this depends on the conditions of occurrence. River and sea sand have rounded particles, while mountain sands consist of acute-angled particles. Mountain sand is often contaminated with harmful impurities, unlike river and sea sand.

Natural sand is a product of weathering (or wind erosion). The weathering process contributes to the destruction of the source material into particles of various diameters, including sand. Nature has the greatest resource - time. And it can grind entire mountains into sand. The wind, together with water, carries sand hundreds and thousands of kilometers. In connection with this, over time, sand deposits may form in the lowlands or at higher elevations. The texture of such sand greatly depends on the way in which small grains of sand were delivered to the deposits.

Water is capable of moving particles of different sizes at the same time. Therefore, very often we can see how deposits with an incredibly variegated pattern and texture are formed next to some obstacle of natural origin. At the same time, the wind performs the function of filtering particles. Wind from different strengths and transports different grains of sand to different distances. In this way, deposits are formed that consist of grains of sand of approximately the same size.

Where does sand come from in deserts? Most of the sand is carried by the wind into deserts. But there are also cases when desert grains are formed by the destruction of mountains. Some deserts were originally the seabed, but many millennia ago the water receded (part of Sazara, see No. 6 “Why”). Sand is also made artificially. Sand is valuable construction material, and quartz sand is used in the glass industry.

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