What is sand made of? Quarry mountain sand. Application of quartz sand

For other uses, see Sand (disambiguation).

Granular material consisting of fine rock and mineral particles

Sand dunes in Idehan Ubari, Libya. Picture of glass sand, dune sand, quartz sand, volcanic sand, coral sand, garnet sand and olivine sand. Samples are from Mongolia, Estonia, Hawaii and the US mainland (1 x 1 cm each).[1]

Sand

This is a granular material consisting of finely dispersed stone and mineral particles. It is determined by size, being finer than gravel and coarser than . Sand can also refer to a soil texture class or soil type; those. soil containing more than 85 percent sand-sized particles by mass.[2]

Sand composition varies depending on local rock sources and conditions, but it is the most common sand component in continental interiors and other regions. Tropical coastal settings are silica (silicon dioxide or SiO2), usually in the form of quartz. The second most common type of sand is calcium carbonate, such as aragonite, which was largely created over the last half-billion years by various life forms such as coral and shellfish. For example, it is the main form of sand found in areas where reefs have dominated the ecosystem for millions of years, such as the Caribbean. Somewhat less commonly, sand may be composed of calcium sulfate, such as gypsum and selenite, as in places such as White Sands National Park and Salt Plains National Wildlife Refuge in the United States.

Sand is a non-renewable resource on a human scale, and sand suitable for concrete manufacture is in high demand.[3] Although there is a lot of desert sand, it is not suitable for concrete. 50 billion tons of beach and fossil sand are used annually for construction.[4]

Composition

Heavy minerals (dark) in quartz beach sand (Chennai, India).
Sand from Coral Pink Sand Dunes State Park, Utah. These are quartz grains with a hematite coating, providing an orange color. Sand from Pismo Beach, California. The components are primarily quartz, damn, volcanic rock, and projectile fragments. The exact definition of sand varies. The scientific Unified Soil Classification System used in engineering and geology corresponds to standard US sieves[5] and defines sand as particles with a diameter of 0.074 to 4.75 millimeters. By another definition, in terms of particle size as used by geologists, sand particles have a diameter between 0.0625 mm (or 1⁄16 mm) and 2 mm. An individual particle in this size range is called a grain of sand

.
The sand grains are found between gravel (with particle sizes ranging from 2 mm to 64 mm in the latter system and from 4.75 mm to 75 mm in the former) and (particles ranging in size from less than 0.0625 mm to 0.004 mm). The size specification for sand and gravel remained the same for over a century, but particles with a diameter of 0.02 mm were considered the Albert Atterberg sand sub-layer standard for use in the early 20th century. The grains of sand in Archimedes' Sand Counter
, written around 240 BC, had a diameter of 0.02 mm. The 1938 USDA specification was 0.05 mm.[6] The 1953 technical standard published by the American Association of State Highway and Transportation Officials sets the minimum sand size to 0.074 mm. Sand feels gritty when rubbed between your fingers. in comparison, it looks like flour.

ISO 14688 labels sand as fine, medium and coarse, ranging from 0.063 mm to 0.2 mm to 0.63 mm to 2.0 mm. In the United States, sand is generally divided into five subcategories based on size: very fine sand (1⁄16 - ​1⁄8 mm diameter), fine sand (1⁄8 mm -1⁄4 mm), medium sand (1⁄4 mm -1⁄2 mm), coarse sand (1⁄2 mm - 1 mm) and very coarse sand (1 mm - 2 mm). These sizes are based on Krumbein's phi scale, where the size in Φ = -log2D; D—particle size in mm. On this scale for sand, the value of Φ varies from -1 to +4, with divisions between subcategories by integers.

Close up of black volcanic sand from Perissa, Santorini, Greece

The most common component of sand in continental interiors and non-tropical coastal areas is silica (silicon dioxide or SiO2), usually in the form of quartz, which, because of its chemical inertness and significant hardness, is the most common mineral resistant to weathering.

The composition of mineral sand varies greatly depending on local rock sources and conditions. Bright white sands found in tropical and subtropical coastal areas are eroded limestone and may contain coral and shell fragments in addition to other organic or detrital material of organic origin, suggesting that sand formation is also dependent on living organisms.[7] The gypsum sand dunes of White Sands National Park in New Mexico are famous for their brilliant white color. Arkose sand or sandstone with significant feldspar content, derived from the weathering and erosion of (usually adjacent) granite rock outcrops. Some sands contain magnetite, chlorite, glauconite, or gypsum. Sands rich in magnetite are dark to black in color, similar to sands formed by volcanic basalts and obsidian. Chlorite-glauconite bearing sands are usually green in color, as are sands derived from basaltic lava with high olivine content. Many sands, especially those common in Southern Europe, have iron impurities in the quartz crystals of the sand, imparting a dark yellow color. Sand deposits in some areas contain garnets and other hardy minerals, including some small gemstones.

What kind of sand is there?

The sand that occurs in nature is a mixture of small grains formed as a result of the destruction and grinding (under the influence of wind, humidity and time) of hard rocks. Depending on the location of the sand and its origin, sand grains can be of different colors, shapes and sizes:

1. Sand, which is mined in quarries, contains many impurities and in its pure form is used only for sprinkling the area for the construction of the foundation of a house. If it is sifted and washed with water, it can be used in construction as an accompanying material.
2. River sand has already been washed with water. Therefore, it is considered the purest and highest quality. Its particles are very small, smooth and suitable for making glass and many building materials.
3. The main “tool” for the formation of sand in the desert is the wind. It is he who destroys rocks and blows their particles into a certain place. In addition, the wind also blows away particles of dried soil, because there is very little moisture in these areas.

Until some time (this was quite a long time ago), European scientists, who had the opportunity to study sands only on the banks of rivers, lakes and seas, believed that in deserts this loose mixture had the same origin. Thus was born the myth that the Sahara was once the bottom of the ocean.

Sources

Rocks are eroded or weathered over long periods of time, mainly by water and wind, and their sediments are transported downstream. These deposits continue to break down into smaller pieces until they become fine grains of sand. The type of rock from which the sediments are formed and the intensity of the environment produce different sand compositions. The most common rock for sand to form is granite, where feldspar minerals dissolve faster than quartz, causing the stone to break into small pieces. In high energy conditions, rocks break down much faster than in calmer conditions. For example, granitic rocks - this means that there are more feldspar minerals in the sand because it would not have had time to dissolve. The term for sand formed by weathering is epiclastic.[8]

River sand is collected either from the river itself or from its floodplain and makes up the majority of the sand used in the construction industry. Because of this, many small rivers have become depleted, leading to environmental problems and economic damage to surrounding areas. The rate of sand extraction in such areas greatly exceeds the rate of sand recovery, making it a non-renewable resource.[9]

Sand dunes are the result of dry conditions or wind-driven deposits. The Sahara Desert is very dry due to its geographical location and is known for its huge sand dunes. They exist here because very little vegetation is able to grow and water is scarce. Over time, the wind carries away all the small particles such as clay and dead organic matter, leaving only sand and larger rocks. Only 15% of the Sahara is sand dunes, and 70% is bare rock.[10] The wind is responsible for creating these different environments and makes the sand round and smooth. These properties make desert sand unsuitable for construction.[11]

Beach sand is also formed by erosion. Over thousands of years, the rocks along the coastline are eroded by the constant movement of waves and sediment accumulates. Weathering and sedimentation in rivers also speed up the process of beach creation, and marine animals interact with the rocks, such as eating algae from them. When there is enough sand, the beach acts as a barrier to prevent further erosion of the land. This sand is ideal for construction because it is angular and comes in a variety of sizes.[12]

Sea sand (or ocean sand) comes from sediments transported into the ocean and from the erosion of ocean rocks. The thickness of the sand layer varies, but there is usually more sand closer to land; this type of sand is ideal for construction and is a very valuable commodity. Europe is a major source of sea sand, which greatly harms ecosystems and local fisheries.[9]

Why does sand form dunes in the desert?

The relief in the desert, oddly enough, can hardly be called monotonous. After all, it is formed by wind and water.

Water flows in sunlit areas, although rare, still sometimes occur. They can be part of deep rivers, the source of which is far beyond the desert (for example, the Ziz River in the Sahara), as well as temporary streams and rivers that appear after heavy rainfalls. Such temporary “reservoirs” bring with them various rocks, which, when dry, form an intricate pattern on the surface.

The wind in the desert affects the rocks located on its territory and blows loose material out of them. Grains of sand that encounter any obstacle on their way (a bush or a piece of rock) are delayed and over time turn into a whole wall, which becomes an obstacle in the path of other grains of sand. Nobody or anything interferes with this process, and gradually the “slide” grows, and its edges move under the wind flow and the shape of a crescent is obtained. This is why sand forms dunes in the desert.

Study

Scanning electron micrograph showing sand grains Seedless sand grains from the Western Desert, Egypt.
Pitting is a result of wind transfer. Studying individual grains can provide much historical information about the origin and mode of transport of the grain.[13] Quartz sand that has recently weathered from granite or gneiss quartz crystals will be angular. It is called grus in geology or sharp sand in construction, where it is preferred for concrete, and in horticulture, where it is used as a soil additive to loosen clay soils. Sand carried long distances by water or wind will have a rounded shape with characteristic abrasion patterns on the surface of the grain. Desert sand is usually round in shape.

People who collect sand as a hobby are known as arenophiles. Organisms that thrive in sandy environments are psammophiles.[14]

Practical use

Sand is widely used in building materials, for washing construction sites, for sandblasting building facades and various products, in housing construction for backfilling, in landscaping courtyard areas and in everyday life (filling paths, installing children's sandboxes, cat toilets, soil in greenhouses, etc.), in the production of mortar for masonry, plastering and foundation work. Widely used in concrete production; in the production of reinforced concrete products, high-strength concrete. An important material in the construction of roads, embankments, as well as in the production of paving slabs, curbs, well rings (in these cases, coarse sand Mk 2.2 - 2.5 is used). Fine construction sand is used to prepare covering mortars. River construction sand is widely used in various decorative (mixed with binding components and dyes to obtain special structural coatings) and finishing works. Construction river sand is a component of asphalt concrete mixtures that are used in the construction and laying of roads. Quartz sands are a valuable raw material for the glass industry.

Uses

Sand grains of yellow construction sand. Microscope Lumam P-8. EPI lighting. A photograph of each grain of sand is the result of multifocal summation.

• Abrasion: Before sandpaper, wet sand was used as an abrasive between rotating devices with elastic surfaces and hard materials such as very hard stone (making stone vases) or metal (removing old stains before repainting copper pans).
• Agriculture: Sandy soils are ideal for growing crops such as watermelons, peaches and peanuts, and their excellent drainage characteristics make them suitable for intensive dairy farming.
• Aquarium: Sand is an inexpensive aquarium base material that some say is better than gravel for home use. This is also necessary for salt water. reef tanks that simulate an environment consisting primarily of aragonite sand broken from coral and shellfish.
• Artificial Reefs: Geotextile sandbags can form the basis for new reefs.
• Artificial islands in the Persian Gulf.
• Beach nourishment: Governments move sand to beaches where tides, storms, or deliberate changes to the shoreline erode the original sand.[15]
• Brick: Manufacturing plants add sand to a mixture of clay and other materials to make bricks.[16]
• Cob: Coarse sand makes up 75% of the cob.
• Specific: Sand is often the main component of this important building material.
• Glass: Silica-rich sand is the main component of common glasses.
• Hydraulic Fracturing: A natural gas drilling technology that uses rounded silica sand as the “proppant,” a material to hold open cracks caused by the hydraulic fracturing process.
• Landscaping: Sand forms small hills and slopes (eg golf courses).
• Mortar: Sand is mixed with masonry cement or Portland cement and lime for use in masonry.
• Paint: Mixing sand with paint produces a textured finish for walls and ceilings or non-slip floor surfaces.
• Railroads: Railroad drivers and operators use sand to improve wheel-to-rail traction.
• Recreational activities: My favorite activity on the beach is playing with sand. One of the most popular uses of sand is to create sometimes complex and sometimes simple structures known as sand castles, the notoriously fickle one. Special children's play areas surrounding a large area of ​​sand, known as sandpits, are common in many public playgrounds and even in some private homes. The sand dunes are also popular with climbers, motorcyclists and beach buggy drivers.
• Roads: Sand improves traction (and therefore driving safety) in icy or snowy conditions.
• Sand animation: Performing artists draw images on the sand. Animation filmmakers use the same term to describe the use of sand on front-lit or backlit glass.
• Sand casting: Moisten or oil the rollers. foundry sand, also known as sand foundry and then mold it into molds into which they pour the molten material. This type of sand must withstand high temperatures and pressures, allow gases to escape, be uniformly fine in size, and not react with metals.
• Sandbags: These protect against flooding and gunfire. The inexpensive bags are easy to transport empty, and unskilled volunteers can quickly fill them with local sand in an emergency.
• Sandblasting: Granular sand serves as an abrasive in cleaning, preparation and polishing.
• Silicon: Quartz sand is the raw material for the production of silicon.
• Heat Weapons: No longer widely used, sand was heated and doused with invading troops during the classical and medieval time periods.
• Water Filtration: Media filters use sand to filter water
• Wuūʾ: an Islamic ritual rubbing of body parts
• Zoanthid "skeletons": animals in this order of marine benthic cnidarians refers to corals and sea anemones, add sand to their mesoglea for structural strength, which they need because they do not have a true frame.

Where does sand come from in the desert?

Not all researchers agree that sand in the desert is the result of wind erosion of sandstones. The main argument refuting this theory of the appearance of grains of sand in the desert is that it would take too much time for the wind to do so. Perhaps this is so, and sand in deserts arises from alluvial deposits (particles brought by water flows).

There are scientists who are confident that all the deserts located at the foot of the mountains appeared as a result of the destruction of rocks under conditions of a sharp change in temperature. These can be considered the Karakum (a consequence of the destruction of the Pamirs) or the Kyzylkum (certain regions of which were formed due to the destruction of the nearby Tien Shan).

Thus, the color, structure and origin of sand in the desert directly depends on where this natural area is located.

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How is sand formed?

• Various natural phenomena, for example, rain, wind, sun, plus for a long time, gradually destroyed mountains, crushed stones, making millions of small grains of sand out of them, that is, sand. The sand contains minerals such as quartz, feldspar and mica. Currently, sand is mainly used in construction (for the preparation of cement, bricks, mortar), and glass production.
• Rocks are exposed to wind, temperature, and water. All this leads to small particles breaking off from the rock. Their sizes range from 0.05...2.5 mm, such particles are called sand. Sand can hide minerals, quartz and silica sand are common. You can also find other minerals. Sand is present everywhere, large reserves along the seashore, all this is the result of the impact of waves and tides on the rocks of the coast. But in the desert, sand is collected by the wind, or in the past they were the bottom of the sea. People actively use sand in many areas of industry.
• Sand is the smallest particles of the original rock, which over many years has been worn away by water, wind and temperature, that is, rocks that have passed through a multi-stage weathering system.

  These factors act together and successfully destroy even hard basalts. The difference in night and day temperatures crumbles the stones, making them smaller and smaller, water washes various substances out of the rock and partially transforms them into other, softer minerals. The wind picks up these small particles and throws them with force onto untouched rocks, sharpening them like an abrasive. Most sand is formed under the influence of water, both in the seas and in rivers and streams. Most modern sandy deserts once had seas.

• From a geological point of view, sand is a sedimentary rock formed in the process of erosion (destruction) of igneous rocks (basalts, diabases, etc.). In simple terms - igneous rock, i.e. volcanic lava poured onto the surface of the Earth and frozen in the form of rocks, under the influence of temperature changes, solar radiation, precipitation, etc. collapses first into large fragments, then into smaller and smaller pieces until it turns into sand
• Sand is formed during the destruction of rocks, mainly containing relatively hard minerals - feldspar, quartz and others. Destruction can occur both mechanical (abrasion and impacts of individual fragments under the influence of flowing water or surf, as well as wind, including with the participation of existing sand), and chemical - everything that is included in the concept of quot; weatheringquot;. At the same time, soft minerals - micas and their weathering products, carbonates, etc. are quickly abraded to a dusty state and carried away by streams of water or air, releasing a fraction of 0.1-5 mm, consisting of fragments of hard minerals and durable fine-crystalline rocks, which is quite mobile, to be separated from larger rocks and redeposited, but is not carried away to the same extent as smaller fractions.
• Sand is a sedimentary rock. It is a product of the destruction of igneous and metamorphic rocks (physical weathering). First, the rocks break down into grains, then these grains are polished by water and wind. Sand always contains quartz as it is the most resistant to weathering. The older the sand, the more quartz it contains. Sand can be marine or continental. Marine is formed in shallow sea conditions and often lies horizontally. Continental is deposited by rivers and temporary streams, or glaciers, or is a product of the aeolian process (typical of deserts).
• Sand is formed in much the same way as water and carbon dioxide. Sand is silicon oxide. Both elements are very common on our planet. There were even options for the development of life along the silicon-organic path, when silicon is present in organic compounds instead of carbon.

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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.

**************************

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).

The word “desert” itself is somehow unpleasant, perhaps even

.

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.

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 area.

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 cleft 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.

NILE

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 sand banks 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 sediments and 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 the 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 grains of sand 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 I’m not happy with this version of the scientists—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 transport it over long distances, where sand 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)

The origin of sand on Earth: echoes of not so ancient cosmic catastrophes

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!

Link

(https://www.livescience.com/28…

The 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 seasons 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 under the influence of the atmosphere Extraterrestrial - massive release of sand during planetary interactions (the scenario described in Velikovsky's book Worlds in Collision) Extraterrestrial - Earth's capture of debris / sand from the solar system after planetary catastrophes such as satellite hijackings. 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? Injection from the planet's interior (mud storms, etc.) Still forming in real time as a result of 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 you have a highly charged object, such as a comet, heading towards the earth, 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 - thereby ending up 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 of 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...

cont.ws

Resources and environmental issues

Only some sands are suitable for the construction industry, for example, for the manufacture of concrete. Due to population and urban growth and resulting construction activity, there is a huge demand for these special types of sand and natural sources are becoming depleted. In 2012, French director Denis Delestrac made a documentary called Sand Wars about the consequences of a lack of construction sand. It shows the environmental and economic impacts of both the legal and illegal trade in construction sand.[17][18][19]

Dredging method is used to extract sand. It works by pumping the top few meters of sand out of the water and pouring it into a boat, which is then sent back to land for processing. Unfortunately, any marine life mixed with the mined sand is killed, and the ecosystem may continue to suffer for years after mining is completed. This not only affects marine life, but also the local fishing industry due to the loss of lives and communities living close to the water. When sand is removed from water, the risk of landslides increases, which can lead to loss of farmland and/or damage to homes.[20]

Numerous uses of sand require significant industrial dredging, raising environmental concerns about overfishing, landslides, and flooding.[21] Countries such as China, Indonesia, Malaysia and Cambodia ban sand exports, citing these problems as a major factor.[22] It is estimated that the annual consumption of sand and gravel is 40 billion tons, and the world's sand production is worth US$70 billion.[23]

Global sand demand in 2021 was 9.55 billion tons in a $99.5 billion industry.[24]

Dangers

Although sand is generally non-toxic, precautions are required when using sand, such as sandblasting. Bags of silica sand used for sandblasting now have labels warning the user to wear respiratory protection to avoid inhaling the fine silica produced. dust. The MSDS for silica sand states that "excessive inhalation of crystalline silica is a serious health problem."[25]

In areas of high pore water pressure, sand and salt water can form quicksand, which is a colloidal hydrogel that behaves like a liquid. Quicksand creates a significant barrier to escape for creatures trapped within, who often die from exposure (rather than immersion) as a result.

see also

• Aggregate (geology) - Mass of rock, gravel, sand, soil particles, or minerals in a rock
• beach - An area of ​​loose particles on the shore of the sea or other body of water
• Construction Aggregate - Coarse and fine grained rocks used in concrete.
• Desert sand (color)
• Dry quicksand
• Energy modified cement - A class of cements that have been mechanically treated to transform reactivity (EMC)
• Deposits of heavy mineral sands and ores
• Oil sands - Type of unconventional oil deposit
• Particle size
• Quicksand - Geological Feature
• Rotating rivers
• Sand Island
• Sand mining
• sand rat
• Sandstone - Type of sedimentary rock
• Sandstorm
• Sand theft - Unauthorized and/or illegal sand mining
• Singing sand - The phenomenon of sand making sound
• White Sands National Park

Recommendations

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2. Glossary of soil science terms
   (PDF). Ottawa: Agriculture Canada. 1976. p. 35. ISBN 978-0662015338.
3. Constable, Harriet (3 September 2021). "How the demand for sand is killing rivers." BBC News Magazine
   . Retrieved September 9, 2021.
4. Albarazi, Hannah. "The Slippery Slopes of the World's Sand Shortage." Retrieved March 29, 2021.
5. Unified Soil Classification System[ permanent dead link
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17. See Sand Wars Teaser here.
18. Simon Ings (26 April 2014). “The climate change story gets a stellar rating.” New Scientist
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19. Strand in Gefara? Arte Future, last updated April 23, 2014
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