Fossil plants. Interesting facts about minerals extracted from the depths of the Earth (15 photos) Nature helps to find deposits

TREASURES OF THE EARTH

Minerals are found in various areas of the Earth. Most deposits of copper, lead, zinc, mercury, antimony, nickel, gold, platinum, and precious stones are found in mountainous areas, sometimes at an altitude of more than 2 thousand meters. m.

On the plains there are deposits of coal, oil, various salts, as well as iron, manganese, aluminum.

Ore deposits have been mined since ancient times. At that time, ore was mined with iron wedges, shovels and picks, and carried out on oneself or pulled out in buckets with primitive cranks, like water from a well. It was very hard work. In some places, ancient miners did enormous work for those times. They carved out large caves or deep, well-like workings in the strong rocks. In Central Asia, a cave carved out of limestone with a height of 15, a width of 30 and a length of more than 40 has still been preserved. m. And recently they discovered a narrow, burrow-like working, going 60 meters deep. m.

Modern mines are large, usually underground, enterprises in the form of deep wells - mines, with underground passages resembling corridors. Electric trains move along them, transporting ore to special

elevators - cages. From here the ore is lifted to the surface.

If the ore lies at a shallow depth, then huge pits are dug - quarries. They operate excavators and other machines. The mined ore is transported by dump trucks and electric trains. In one day, 10-15 people, working on such machines, can extract as much ore as 100 people could not previously produce with a pick and shovel in a year of work.

The amount of ore mined increases every year. More and more metals are needed. And it was no coincidence that anxiety arose: would the mineral resources soon be exhausted and there would be nothing left to mine? Economists even made calculations, the results of which were disappointing. For example, it was calculated that when modern speed Once developed, the reserves of known nickel deposits around the world will be completely depleted in 20-25 years, tin reserves in 10-15 years, and lead reserves in 15-20 years. And then the “metal hunger” will begin.

Indeed, many deposits are rapidly depleted. But this applies mainly to those deposits where ores reached the surface of the Earth and have been developed for a long time. Most of these deposits have actually been partially or completely depleted over several hundred years of mining. However, the Earth is the richest storehouse of

mineral resources, and it is too early to say that the riches of its subsoil have been exhausted. There are still many deposits near the surface of the Earth, many of them lie at great depths (200 or more meters from the surface). Geologists call such deposits hidden. They are very difficult to find, and even an experienced geologist can walk over them without noticing anything. But if earlier a geologist, going in search of deposits, was armed only with a compass and a hammer, now he uses the most complex machines and instruments. Scientists have developed many in various ways search for minerals. The deeper nature has hidden reserves of valuable ores, the more difficult it is to discover them, and therefore, the more perfect the methods of searching for them must be.

HOW TO SEARCH FOR DEPOSITS

Since man began to smelt metals from ores, many brave ore miners have visited the difficult taiga, the steppes and inaccessible mountains. Here they looked for and found mineral deposits. But the ancient ore miners, although they had generations of experience in searching for ores, did not have enough knowledge for scientifically based actions, so they often searched blindly, relying “on instinct.”

Often large deposits were discovered by people not associated with geology or mining - hunters, fishermen, peasants and even children. In the middle of the 18th century. peasant Erofei Markov, looking for rock crystal in the Urals, found white quartz with shiny grains of gold. Later, a gold deposit called Berezovsky was discovered here. Rich mica deposits in the 40s of the 17th century. in the river basin The hangars were found by the townsman Alexei Zhilin. The little girl opened the South Africa the largest diamond deposit in the capitalist world, and the first Russian diamond was found in the Urals in 1829 by a 14-year-old serf boy, Pavlik Popov.

Large accumulations of a valuable stone - malachite, from which various jewelry is made, were found for the first time in the Urals by peasants while digging a well.

A deposit of beautiful bright green precious stones - emeralds - was discovered in the Urals in 1830 by resin farmer Maxim Kozhevnikov, when he was uprooting stumps in the forest. Over 20 years of development, 142 pounds of emeralds were extracted from this deposit.

One of the mercury deposits (Nikitovskoe in Ukraine) was accidentally discovered by a student who saw a bright red mercury mineral - cinnabar - in the adobe wall of a house. In the place from which the material for building the house was transported, there turned out to be a large deposit of cinnabar.

The development of the northern regions of the European part of the USSR was hampered by the lack of a powerful energy base. Coal, necessary for industrial enterprises and cities of the North, had to be transported from the south of the country several thousand kilometers away or purchased in other countries.

Meanwhile, in the notes of some travelers of the 19th century. indicated the discovery of coal somewhere in the north of Russia. The reliability of this information was questionable. But in 1921, an old hunter sent to Moscow “samples of black stones that burn hot in a fire.” He collected these flammable stones together with his grandson near the village of Ust-Vorkuta. The coal turned out to be of high quality. Soon an expedition of geologists was sent to Vorkuta, which, with the help of Popov, discovered the large Vorkuta coal deposit. Subsequently, it turned out that this deposit is the most important section of the Pechora coal basin, the largest in the European part of the USSR.

In the river basin Vorkuta soon grew into a mining town, and a railway was built to it. Now the city of Vorkuta has become the center of the coal industry in the European North of our country. Metallurgy and the chemical industry of the North and North-West of the USSR are developing on the basis of Vorkuta coals. The river and sea fleets are provided with coal. So the discovery of the hunter led to the creation of a new mining center and solved the energy problem for a huge region of the Soviet Union.

No less interesting is the history of the discovery of magnetic iron ores by the pilot M. Surgutanov. He served state farms and various expeditions in the Kustanai steppe east of the Urals. Surgutanov carried people and various cargo on a light plane. On one of the flights, the pilot discovered that the compass no longer showed the correct direction: the magnetic needle began to “dance.” Surgutanov suggested that this is due to magnetic

an anomaly. Having finished his flight, he headed to the library and found out that similar anomalies occur in areas where powerful deposits of magnetic iron ores occur. On subsequent flights, Surgutanov, flying over the anomaly area, marked on the map the places of maximum deviations of the compass needle. He reported his observations to the local geological department. A geological expedition equipped with drilling rigs drilled wells and discovered a powerful iron ore deposit at a depth of several tens of meters - the Sokolovskoye deposit. Then the second deposit was discovered - Sarbaiskaya. The reserves of these deposits are estimated at hundreds of millions of tons of high-quality magnetic iron ore. Currently, one of the country's largest mining and processing plants with a capacity of several million tons of iron ore per year has been created in this area. A mining town, Rudny, arose near the plant. The services of pilot Surgutanov were highly appreciated: he was awarded the Lenin Prize.

In most cases, prospecting and discovery of deposits require serious geological knowledge and special auxiliary work, sometimes very complex and expensive. However, in a number of cases, ore bodies come to the surface on mountain slopes, in cliffs of river valleys, in river beds, etc. Such deposits can also be discovered by non-specialists.

Behind last years Our schoolchildren are taking an increasingly active part in studying the mineral resources of their native land. During the holidays, high school students go on hiking trips. native land. They collect rock and mineral samples, describe the conditions in which they found them, and map the bridge where the samples were taken. At the end of the hike, with the help of a qualified leader, the practical value of the collected rocks and minerals is determined. If any of them are of interest to the national economy, then geologists are sent to the location of the find to check and evaluate the found deposit. Thus, numerous deposits of building materials, phosphorites, coal, peat and other minerals were found.

To help young geologists and other amateur prospectors, a series of popular books on geology have been published in the USSR.

Thus, the search for deposits is accessible and feasible to any observant person, even without special knowledge. And the wider the circle of people who are included in the search, the more confidently we can expect the discovery of new deposits of minerals needed national economy THE USSR.

However, you cannot rely only on random discoveries by amateur search engines. In our country, with its planned economy, we must look for sure. This is what geologists do, knowing what, where and how to look.

SCIENTIFICALLY BASED SEARCHES

Before you start searching for minerals, you need to know the conditions under which certain deposits are formed.

A large group of deposits was formed with the participation of the internal energy of the Earth in the process of penetration of fiery liquid melts - magmas - into the earth's crust. Geological science has established a clear relationship between the chemical composition of intruded magma and the composition of ore bodies. Thus, deposits of platinum, chromium, diamonds, asbestos, nickel, etc. are associated with igneous rocks of black-green color (dunites, peridotites, etc.). Deposits of mica, rock crystal, and topaz are associated with light, quartz-rich rocks (granites, granodiorites). and etc.

Many deposits, especially of non-ferrous and rare metals, were formed from gases and aqueous solutions that separated when magmatic melts cooled at depth. These gases and solutions penetrated into cracks in the earth's crust and deposited their valuable cargo in them in the form of lens-shaped bodies or plate-shaped veins. Most deposits of gold, tungsten, tin, mercury, antimony, bismuth, molybdenum and other metals were formed in this way. In addition, it was established in which rocks certain ores were precipitated from solutions. Yes, lead- zinc ores are more common in limestones, and tin-tungsten - in granitoids.

Sedimentary deposits, formed in past centuries as a result of sedimentation of mineral matter in water basins - oceans, are very widespread on Earth.

seas, lakes, rivers. In this way, many deposits of iron, manganese, bauxite ( aluminum ore), rock and potassium salts, phosphorites, chalk, native sulfur (see pp. 72-73).

In places of ancient sea coasts, lagoons, lakes and swamps, where large quantities Plant sediments accumulated, and deposits of peat, brown and coal were formed.

Ore sedimentary deposits have the form of layers parallel to the layers of the sedimentary rocks that host them.

Accumulation various types mineral resources did not occur continuously, but in certain periods. For example, most of all known sulfur deposits were formed in the Permian and Neogene periods history of the Earth. Masses of phosphorites in our country were deposited in the Cambrian and Cretaceous periods, the largest deposits of hard coal in the European part of the USSR were deposited in the Carboniferous period.

Finally, on the surface of the Earth, as a result of weathering processes (see page 107), deposits of clays, kaolin, silicate nickel ores, bauxite, etc. can appear.

A geologist, going on a search, must know what kind of rocks the search area is composed of and what deposits are most likely to be found in it. A geologist must know how sedimentary rocks lie: in which direction the strata are elongated, how they are inclined, i.e. in which direction they plunge into the depths of the Earth. This is especially important to take into account when searching for minerals that were deposited on the seabed or in sea bays in the form of layers parallel to rock layers. This is how, for example, layered bodies of coal, iron, manganese, bauxite, rock salt and some other minerals occur.

Layers of sedimentary rocks may lie horizontally or be folded into folds. Large accumulations of ores sometimes form at the bends of folds. And if the folds have the shape of large, gently sloping domes, then oil deposits can be found in them.

Geologists try to find fossilized remains of animal and plant organisms in sedimentary rocks, because they can be used to determine in what geological era these rocks were formed, which will facilitate the search for minerals. In addition to knowing the composition

rocks and the conditions of their occurrence, you need to know the search signs. So, it is very important to find at least some ore minerals. They are often located near the deposit and can tell you where to look for ore more carefully. Thin plate-like bodies (veins), composed of non-metallic minerals - quartz, calcite, etc., are often located near ore deposits. Sometimes some minerals help to find deposits of other, more valuable ones. For example, in Yakutia, diamonds were searched for by the bright red minerals accompanying them - pyropes (a type of garnet). In places where ore deposits occur, the color of rocks is often changed. This happens under the influence of hot mineralized solutions rising from the bowels of the Earth on the rocks. These solutions penetrate through cracks and change the rocks: they dissolve some minerals and deposit others. Zones of altered rocks that form around ore bodies often have a large

Hard rocks rise in the form of ridges among the destroyed softer rocks.

severity and are clearly visible from a distance. For example, altered orange-brown granites clearly stand out among the usual pink or gray ones. As a result of weathering, many ore bodies acquire striking colors. A classic example is the sulfur ores of iron, copper, lead, zinc, and arsenic, which, when weathered, acquire bright yellow, red, green, and blue colors.

Landforms can tell a prospecting geologist a lot. Different rocks and minerals have different strengths. A piece of coal is easy to break, but a piece of granite is difficult. Some rocks are quickly destroyed by the sun, wind and moisture, and pieces of them are carried down from the mountains. Other rocks are much harder and break down more slowly, so they rise up in the form of ridges among the destroyed rocks. They can be seen from afar. Look at the photo on page 94 and you will see ridges of strong rock.

In nature, there are ores that are destroyed faster than rocks and in their place depressions are formed, similar to ditches or pits. A geologist checks such places and looks here

Search engines pay special attention to ancient workings. Our ancestors mined ore in them several centuries ago. Here, at a depth where ancient miners could not penetrate, or near ancient workings, there may be an ore deposit

Sometimes the places where ore occurs are told by the old names of settlements, rivers, lairs, and mountains. Thus, in Central Asia, the names of many mountains, lairs, and passes include the word “kan,” which means ore. It turns out that ore was found here a long time ago, and this word became part of the name of the place. Geologists, having learned that there was a ravine or mountains in the area with the word “kan” in their names, began to look for ore and sometimes found deposits. In Khakassia there is Mount Temir-Tau, which means “iron mountain”. It was named so because of the brown deposits of oxidized iron ore.

There was little iron in the mountain, but geologists found more valuable ore here - copper.

When a geologist searches for deposits in any area, he also pays attention to water sources: he finds out whether the water contains dissolved minerals. Often even small sources

Such ditches are dug to determine what rocks are hidden under a layer of soil and sediment.

can tell you a lot. For example, in the Tuvan Autonomous Soviet Socialist Republic there is a source to which sick people come from far away. The water of this source turned out to be highly mineralized. The area surrounding the source is covered with dark brown rusty iron oxides. In winter, when the spring water freezes, brown ice forms. Geologists have discovered that here underground water penetrates through cracks into the ores of the deposit and brings dissolved chemical compounds of iron, copper and other elements to the surface. The source is located in a remote mountainous area, and geologists for a long time didn't even know about its existence.

We briefly looked at what you need to know and what prospecting geologists have to pay attention to along the route. Geologists take samples from rocks and ores to accurately identify them using a microscope and chemical analysis.

WHY DO YOU NEED A GEOLOGICAL MAP AND HOW IS IT COMPLETED?

Geological maps show what rocks and what age are located in one place or another, in what direction they extend and plunge to depth. The map shows that some rocks are rare, while others stretch for tens and hundreds of kilometers. For example, when they compiled a map of the Caucasus, it turned out that granites stretch almost along the entire mountain range. There are many granites in the Urals, Tien Shan and other mountainous regions. What do these rocks tell a geologist?

We already know that in granites themselves and in igneous rocks similar to granites, there are deposits of mica, rock crystal, lead, copper, zinc, tin, tungsten, gold, silver, arsenic, antimony, mercury, and in dark-colored igneous rocks - dunites, gabbros, peridotites - chromium, nickel, platinum, and asbestos are concentrated.

Knowing which rocks are associated with deposits of certain minerals, you can reasonably plan their searches. Geologists compiling a geological map have found that Yakutia contains the same igneous rocks as South Africa. Subsoil prospectors concluded that diamond deposits should be looked for in Yakutia.

Drawing up a geological map is a large and difficult job. It was carried out mainly during the years of Soviet power (see pp. 96-97).

To create a geological map of the entire Soviet Union, geologists had to explore one area after another for many years. Geological parties passed through river valleys and their tributaries, along mountain gorges, and climbed steep slopes of ridges.

Depending on the scale of the map being compiled, routes are laid. When drawing up a scale 1 map: the geologists' routes pass at a distance of 2 km one from the other. During the geological survey, the geologist takes rock samples and makes notes in a special route notebook: notes what rocks he encountered, in which direction they stretch and in which direction they plunge, describes the folds encountered, cracks, minerals, changes

rock colors. Thus, it turns out, as shown in the figure, that geologists seem to divide the study area into squares that form a grid of routes.

Often rock formations are covered by thick grass, dense taiga forests, swamps or a layer of soil. In such places you have to dig up the soil, revealing rocks. If the layer of soil, clay or sand is thick, then wells are drilled, pits similar to wells are made, or even deeper mining openings are made - mines. In order not to dig holes, the geologist can go not along straight routes, but along the beds of rivers and streams, in which there are natural outcrops of rocks or rocks in places protrude from under the soil. All these rock outcrops are plotted on a map. And yet, on a geological map compiled along routes located approximately 2 km, Not everything is shown: after all, the routes are located at a far distance from one another.

If you need to find out in more detail what rocks lie in the area, then the routes lead closer to each other. The figure on the left shows routes located one from another at a distance of 1 km. On each such route, the geologist stops and takes rock samples after 1 km. As a result, a geological map of scale 1: is compiled, i.e. more detailed. When geological maps of all regions were collected and connected, we got one large geological map of our entire country. On this map

During a geological survey, the area under study is divided into a conventional grid, along which the geologist leads his routes.

it is clear that, for example, granites and other igneous rocks are found in the mountain ranges of the Caucasus, the Urals, Tien Shan, Altai, Eastern Siberia and other regions. Therefore, deposits of copper, lead, zinc, molybdenum, mercury and other valuable metals must be looked for in these areas.

To the west and east of the Ural Range - on the Russian Plain and within the West Siberian Lowland - sedimentary rocks and the minerals deposited with them are widespread: coal, oil, iron, bauxite, etc.

In places where minerals have already been discovered, the search is carried out even more thoroughly. Geologists walk along route lines located at a distance of 100, 50, 20 and 10 m one from the other. These searches are called detailed searches.

On modern geological maps of scales 1: , 1: and larger, all rocks are plotted, indicating their geological age, with data on large cracks (faults in the earth’s crust) and ore outcrops on the surface.

A geological map is a faithful and reliable assistant to a search engine; without it it is very difficult to find deposits. With a geological map in hand, a geologist confidently goes on a route, because he knows where and what to look for.

Scientists have thought a lot about how to facilitate and speed up the search for ore, and have developed various methods for exploring the bowels of the Earth for this purpose.

NATURE HELPES TO SEARCH FOR DEPOSITS

Imagine that geologists are searching in the remote, dense taiga of Eastern Siberia. Here the rocks are covered with soil and dense vegetation. Only occasionally do small rock formations rise among the grass. Nature, it seems, has done everything to hide its riches from humans. But it turns out that she miscalculated something, and geologists take advantage of this.

We know that rain, snow, wind and sun constantly and tirelessly destroy rocks, even such strong ones as granite. Over hundreds of years, rivers have cut deep gorges into granites.

Destructive processes lead to cracks appearing in rocks, pieces of rocks falling off and rolling down, some fragments fall into streams and are carried away by water into rivers. And in them these pieces roll, round into pebbles and move further, into more large rivers. Along with the rocks, the ores contained in them are also destroyed. Pieces of ore are carried into the river and move along its bottom over long distances. Therefore, when searching for ores, a geologist looks at the pebbles that lie at the bottom of the river. In addition, he takes a sample of loose rock from the river bed and washes it with water in a trough-like tray until all the light minerals are washed away and only grains of the heaviest minerals remain at the bottom. These may include gold, platinum, minerals of tin, tungsten and other elements. This work is called washing of concentrates. Moving upstream of the river and washing the concentrates, the geologist ultimately determines where the valuable minerals were removed from and where the ore deposit is located.

The spot search method helps to find minerals that are chemically stable, have significant strength, do not wear out, and are preserved after long-term transfer and rolling in rivers. But what if the minerals are soft and, as soon as they fall into a stormy mountain river, they are immediately ground into powder? For example, such long journeys as gold makes, the minerals of copper, lead, zinc, mercury, and antimony cannot withstand. They not only turn into powder, but also partially oxidize and dissolve in water. It is clear that the geologist will be helped here not by the schlich method, but by another method of searching.

Fossils are animals and plants of the geological past (see Development of life on Earth). They are studied by the remains and traces of life activity preserved in sedimentary deposits of the earth's crust.

You can get acquainted with them by taking a tour along steep river banks made of limestone or sandstone, along quarries, mountains with steep slopes not covered by soil. Under your feet and on steep stone walls you can see a wide variety of fossilized shells. There are large accumulations of ammonite shells - one of the large groups cephalopods, which appeared on Earth about 350 million years ago and became extinct about 70 million years ago. Sometimes the top layer of the shell is missing, and the well-preserved inner - mother-of-pearl - layer shimmers with all the colors of the rainbow. The flower-like skeletons of peculiar animals - sea lilies, which appeared in the seas about 500 million years ago, are beautifully intertwined.

An indelible impression remains from walking along the bottom of the sea, which existed about 300 million years ago. It can be done, for example, on the banks of the Meta River in the Novgorod region. Large slabs of limestone, formed from sediments in the coastal parts of the so-called Carboniferous Sea, are literally strewn with large shells of brachiopods - a peculiar group of animals that flourished in the seas of the distant past. In modern seas they are represented by a small number of forms and do not reach large sizes.

Many of you are familiar with the so-called “devil's fingers” or “thunder arrows”, which can often be found along the banks of the Oka and Volga rivers, in the Crimea, in the Caucasus and other places. This is the most durable part of the shell of belemnites - distant relatives of modern squids.

Sometimes the skeleton dissolves, and only an impression of it remains in the rock, which is called the core. He is educated mineral substance, brought by water. Such nuclei form especially well when various shells are dissolved. Often, only an imprint of the skeleton remains in the rock, from which it is difficult to judge the structure of the animal.

Sometimes even the formation of the breed itself is associated with mass gathering remains of extinct organisms. They can be seen under a microscope in a preparation made from ordinary writing chalk. Fusuline limestone is known, formed by simple organisms similar to tiny spindles - fusulins, which lived more than 200 million years ago. Nummulite limestone is found in Crimea, formed by large coin-shaped skeletons of single-celled organisms - nummulites, which lived in warm seas more than 50 million years ago. It is not uncommon to see layers of limestone composed of the skeletons of extinct corals, which in the seas of the distant past formed reefs, like their descendants in modern seas.

Skeletons of marine vertebrates, such as fish, are also found, sometimes forming entire clusters. There are known remains of large marine reptiles - ichthyosaurs, which became extinct about 70 million years ago.

Well-preserved and sufficiently complete remains of terrestrial animals are rare, since they are destroyed by predators or they decompose, and the skeletons are destroyed in the air. From vertebrate animals, usually only the largest bones, skulls, and less often other parts of skeletons remain. Findings of natural casts of the brain and parts of the skeleton with preserved tendons are extremely rare and unique. Only under special conditions can soft tissues, in addition to the skeleton, be preserved, of course dehydrated and, as it were, mummified. IN northern regions In Siberia, in conditions of centuries-old permafrost, perfectly preserved parts of animals, and sometimes even entire mammoths and other representatives of the fauna, are found ice age. It is interesting that in such mammoths not only the skin and wool are well preserved, but even the insides and contents of the stomach, which can be used to determine what they ate.

Animal remains are perfectly preserved in natural asphalt-like masses. Here they find preserved corpses of not only animals, but also birds. Perhaps they, mistaking the shiny surface of such a mass for a lake, sat on it and drowned in the viscous asphalt.

Insects trapped in the resin of coniferous trees that grew on Earth millions of years ago are well preserved. In this fossilized resin (amber), the smallest details of the structure of insects are often visible.

Sometimes scientists encounter only traces of the vital activity of organisms: burrows, footprints, remains of meals. These findings can tell a specialist a lot about the animal’s lifestyle and behavior. The traces of giant reptiles - dinosaurs, which dominated the Earth for more than 100 million years and became extinct about 70 million years ago, are well known. Some of them walked on two legs and reached a height of 15 m.

Fossil plants are also known. Traces have been preserved not only from higher plants, with fairly strong trunks and leaves, but even from algae. Many groups of algae are capable of forming peculiar calcareous cases, others have microscopic shells of silica, etc., due to which they are well preserved in a fossil state. Silica shells of one of the groups of algae - diatoms form quite thick deposits of light material used in industry. Parts of algae are well preserved in the oil shale they form.

From land plants, imprints of leaves and the leaves themselves in the form of thin carbon films, as well as fruits and trunks, have reached us. They are usually found in scattered form, and it is very difficult to restore a whole plant from such remains. Particularly impressive are the clusters of huge trunks, reminiscent of the columns of a long-abandoned temple or theater.

But perhaps the most amazing thing is the preservation of spores and pollen of different plants. Pollen has been preserved in large quantities, and thanks to it our information about flora of the past.

The remains of tree-like lepidodendrons and sigillaria, which became extinct about 300 million years ago, are quite often found in layers of coal, in the formation of which they took part. Due to the abundance of coal, one of the periods of the geological history of the Earth was called Carboniferous. However, one should not think that all the coal on Earth was formed only at this time; this process was repeated several times and under different conditions.

They are not always clearly aware of the inextricable connection between the world of the present and the world of the past. It should be remembered that the world in which we live is the result of a long evolution of the world of the past and is closely intertwined with it. We use the wealth created by nature over tens and hundreds of millions of years: limestones, oil shale, coal, oil, which also owes its origin to long-extinct organisms, and must use them wisely, because they are irreplaceable.

Man did not immediately learn to read the chronicle of the Earth. As human society developed, people gradually learned the world. They had a desire to somehow explain the fossilized shells, huge tusks and bones found high in the mountains that were not similar to the bones of modern animals. The explanations were sometimes the most fantastic. Thus, large animal bones were mistaken for the bones of giants.

Only at the turn of the 18th and 19th centuries. the true nature of all these remains was established. Paleontology appeared - the science of ancient organisms. Modern paleontology is a complex science. It is divided into paleozoology - the science of fossil animals, paleobotany - the science of fossil plants, paleoecology - the science of the lifestyle and living conditions of organisms of the past. Now paleontologists not only describe appearance fossil remains, as was done in the last century. They examine its internal structure on cuts, in thin sections, and etch it in acids to study its structure. In their work, paleontologists use light and electron microscopes, X-rays and infrared rays.

A detailed study of fossil remains is important not only for elucidating the history of development organic world Earth. It helps to establish the sequence of formation of sedimentary deposits containing minerals, to find out how the climate changed, and to restore the picture of the distribution of land and seas in the distant geological past.

The world of animals and plants hundreds of millions of years ago was little like today. There was a time when all life was concentrated in the seas, then organisms mastered the land and only then mastered the airspace. Many large groups of animals and plants appeared a very long time ago and exist to this day (for example, crocodiles, turtles, among plants - cycads, ferns), others, which flourished for tens and even hundreds of millions of years, died out without a trace. Unfortunately, the remains of all extinct organisms do not always reach us. There were probably many more extinct groups than we know about.

The continuous change of different groups of animals and plants, the appearance of some and the extinction of others, allowed scientists to divide the entire history of the development of the organic world into several large stages - eras (see Development of life on Earth), each of which is divided into substages - periods, and periods - into geological century. The deposits that arose at one time or another got their names. From fossil remains, scientists can determine the relative age of the sediments in which they were found. Establishing the age of layers of the earth's crust from the fossil remains of organisms is a special science - biostratigraphy. Based on these data, special geological maps are compiled, necessary for searching for minerals, on which deposits of a certain age are indicated in a certain color.

For a long time, veterinarians in the county of Somersetshire, located in southwest England, could not find out the cause of frequent and rather strange diseases. cattle. Beautiful pastures with succulent nutritious herbs At first they did not arouse any Suspicion. However, in 1938, after careful investigation, it was discovered that clover and some other leguminous plants that were sown in Somersetshire pastures contained large amounts of molybdenum.

It turns out that local soils were underlain by rocks rich in this element. Plants, feeding on subsoil solutions, absorbed the molybdenum present in them and gradually accumulated it in the leaves and stems. He was the one who destroyed internal organs animals. “Molybdenosis” is what scientists called this terrible disease.

The ability of some plant species to concentrate iron, tin, copper, gold, etc. in their tissues was noticed at the beginning of the 18th century by the Swedish chemist Urban Ierne.

Geologists have pondered the remarkable features of piggy bank plants. Delicate galmaine violets, which collect zinc in their stems, grow, as a rule, where zinc ores are found... Prickly thickets of cachima, simply called tumbleweeds, prefer to live where copper is hidden... A new one was opening up before geologists, original way searching for minerals with the help of green friends.

Nowadays, a lot of interesting information has been collected about indicator plants, as scientists call them.

In 1956-1957, in one of the southern regions of our country, geobotanists discovered a strange variety of wild poppy. The petals of its flowers seemed to be cut into small pieces by a sharp lancet. It turned out that the poppy tissue contained lead, which apparently affected the appearance of the plant. Having unraveled the secret of the disease of wild poppy, geologists carefully studied the area in which it grew, and soon discovered deposits of lead ores.

In the steppes you can often find the biyurgun plant. It has an elongated stem with characteristic narrow leaves. However, sometimes biyurgun is quite difficult to recognize. The plant loses its slenderness, looks stunted and stunted. It has been established that the culprit of this metamorphosis is the chemical element boron.

The flower, widespread in the South Ural steppes, helps geologists in their search for nickel deposits. In a common nurse, small yellow flowers form a kind of panicle at the end of the stem. If the baby grows where nickel ores are hidden, the appearance of the flower changes dramatically. The panicle disappears, and the flowers are located throughout the stem. The color of the petals also changes - from yellow they become crimson. A similar phenomenon occurs with anemones, which, like hairy breastworts, accumulate nickel in their stems. The anemone's corolla consists of blue petals. In “nickel” anemones, the petals become very pointed and turn pale, turning light blue.

This means that the presence of new elements in the tissues of the plant leaves an imprint on its appearance. Therefore, any changes in a familiar plant should alert a geobotanist.

However, not only flowers help geologists find minerals. Shrubs and trees can serve as excellent indicators.

Thus, in the US state of Ohio, prospectors noticed that honeysuckle bushes grew on the soils that covered gold-bearing veins. Chemical analysis revealed the presence of gold and silver in the leaves of this plant. Later, the honeysuckle bushes served as an excellent reference point for gold miners. But another shrub - astrogalus - helps to search for deposits of selenium and uranium ores.

An interesting pattern was noticed by geobotanists in the location of coal deposits on Sakhalin. They are mainly concentrated where there are many birch forests. As you know, birches prefer clay soils, and coal seams on Sakhalin lie in clays and limestones. However, a reservation should be made: this “birch” method of searching for coal deposits cannot be blindly applied in all areas.

Every year geobotanists find more and more indicator plants. Those who participate in hikes and dream of becoming a geologist need to be well aware of the green scouts who help uncover the secrets of the underground storeroom.

The department is led by S. Glushnev

You can also read about green scouts - the inseparable companions of metals in the following books and magazines:
1. Vinogradov A.P., Searches for ore deposits using plants and soils. Proceedings of the biochemical laboratory. That X. Publishing House of the USSR Academy of Sciences, 1954.
2. Malyuga D.P., About soils and plants as a search feature for metals. Proceedings of the USSR Academy of Sciences, Geological Series K" 3, 1947
3. Malakhov A.A., Secret signs of earth treasures. Magazine "Ural" No. 8 for 1958.
4. Viktorov A., The mystery of treasure hunting. Magazine "Technology for Youth" No. 3 for 1957.

If you ski and are outside the city, of course, not where dozens and hundreds of skiers have plowed the snow in all directions with their tracks, but further away, where the surface of recently fallen snow is untouched, pay attention to the tracks of animals and try to explain who they are left. Learn to distinguish the tracks left by a hare, fox, dog, wolf, crow, sparrows or other small birds.

Bird tracks are easy to distinguish by their shape and by the fact that they end suddenly and near the paw prints you can see the stripes left by the wings during takeoff.

It is also interesting to observe traces on the surface of loose sand away from wells, where they are not trampled by cattle going to water. There you can see traces of a hare, fox, gopher, lizards, different birds and even beetles and snakes. If you spend a few hours hiding in the bushes to test your guesses, you might see some of those who leave these traces.

On the wet sand or silt of the flat shores of lakes and seas, on the viscous clay of takyr, freed from water, you can also observe traces of various animals, which will be more durable than traces on snow or sand. The latter will be destroyed by the next snowfall or wind, and the traces on the clay will dry out along with the clay and will remain until the next flooding, which will not destroy them, but will cover them with a new layer of clay, that is, make them fossils (Fig. 272).

Many years later, when the sea recedes or modern coastal sediments are raised higher, weathering or erosion processes destroy the clay that covered the traces, and some researcher will notice and describe them.

Such fossil traces have already been encountered by scientists from different countries and described by them. These are traces of large and small reptiles wandering along the wet shore of a lake or sea (Fig. 273), the soft soil of which was deeply pressed under their weight, traces of worms and crustaceans crawling along the wet silt of the coast. They were covered with fresh sediment during flooding and were preserved.

And so we accidentally learned that there are not only fossil animals and plants, but even surviving fossil traces, ephemeral, that is, easily disappearing: the prints of the feet of a running animal or the body of a crawling animal. Now we will not be surprised that even the imprints of individual raindrops that fell on the dry shore of a lake or sea are preserved in fossil form, representing round flat depressions of different diameters, surrounded by a barely noticeable roller, which the drop knocked out on the surface of silt or clay (Fig. 274) .

Traces of the wave movement of water are preserved in the form of the so-called wave ripples and current ripples, i.e. those irregularities that are created on the surface of a sandy or clay bottom by a slight disturbance of the water of a lake or sea or the flow of a river (Fig. 275). These traces consist of flat ridges, separated from each other by grooves, flat depressions and similar to the ripples that the wind creates on the surface of the sand, as we already know (). They are often incorrectly called wave marks, that is, they are associated with scallops that form on the shore; the latter are much less common and have different outlines (Fig. 276).

By carefully studying their structure, the shape of the scallops and the coarseness of the grains on the scallops and in the grooves, it is possible to determine whether these ripples are created by wind on land, current or waves under water, and determine the direction of the current, waves and wind.

In a cliff of a river bank or on the slope of a ravine, in the wall of a pit in which sand or brick clay is mined, you can see gray and black round or irregular spots of different sizes under a layer of dark plant soil or black soil, in the yellow subsoil. These are fossil molehills or animal burrows filled with material from above; they contain the bones of these animals or the remains of their food. On blocks of some rocks, especially limestones, on the seashore, above its modern level, one often comes across a large number of strange, deep pits. These are holes drilled by bivalves that sat in these holes at a time when the water level was higher and covered them. Even the valves can be found in the pits. They prove that the shore has risen, or that the sea has retreated, that its bottom has sank.

All these traces represent documents by which one can judge the distant past of our Earth. They are similar to those manuscripts that are stored in archives and by which the historian judges past events in the life of a given state. The historian studies not only the contents of the manuscript, but also the typeface, the image of individual letters, which has changed over time; he studies the color and quality of the paper, the color of the ink or ink with which the manuscript is written. More ancient documents were written not on paper, but on parchment made from leather, on papyrus made from the lotus plant.

Even more ancient documents were not written with ink or ink, but were carved on wooden tablets or pressed onto clay tablets, which were then fired. And even more ancient ones, from those times when man had not yet invented signs to depict the words of his speech, but had already learned to draw the animals he hunted or fought with for his life, represent drawings made in red or black paint on the walls of caves, on the smooth surface of the cliffs or gouged out on them with a chisel (Fig. 277). All these documents are necessary for the historian, archaeologist and anthropologist to find out the history of man.

And the drawings ancient man are also interesting for a geologist, since they give an idea of ​​​​the animals that existed at the same time as him. Thus, the image of a mammoth (Fig. 277), for all its roughness, still conveys correctly and general shape body, and the position of the tusks, especially the hairiness, which indicates its life in a cold climate. In this regard, it is indicative to compare this ancient drawing with the reconstruction of a mammoth made by modern scientists based on the findings of entire corpses of this animal in permafrost soil in northern Siberia ().

The history of the Earth is also studied from documents, from the traces that we have indicated, and from even more numerous ones that are left by all geological processes, carrying out their work of creating and transforming the face of the Earth. The totality of these traces represents a huge geological archive, which the geologist must learn to disassemble and interpret, just as a historian disassembles and interprets the manuscripts of the state archive.

The geologist follows these traces step by step, carefully studying them, comparing them with each other, combining his observations in order to ultimately come to certain conclusions. A geologist is essentially a pathfinder.

Thus, the first task of the geologist-pathfinder is to study outcrops - natural outcrops of rocks, wherever they are found in the area under study. He must determine what rocks make up the outcrop, in what order they lie on top of each other, what their composition and color are, whether they lie horizontally or dislocated, conformably or disconformably. He must determine the strike and dip of layers, if they are broken, as well as cracks, if the latter form correct systems, crossing all layers.

If the outcrop consists of igneous rock, the pathfinder's tasks change somewhat. The intrusive rock will either be a monotonous mass in which you will have to measure cracks and the location of crystals, from which you can determine the direction of the flow of magma; or it will be possible to notice in it inclusions of some other rocks captured during the invasion, or the so-called schlieren - accumulations of one of the minerals that make up the rock (dark, for example black mica, less often light - feldspar, quartz).

Layering can be found in volcanic rocks - the intermittency of lava flows of different composition and structure, or the intermittency of lava and tuff. Then you need to determine their occurrence.

The presence of igneous and sedimentary rocks in the same outcrop complicates the pathfinder's tasks. We found, for example, that granite is in contact with a layer of sedimentary rock consisting of sandstone (Fig. 281). A careful study of the boundary between them, the so-called contact, will show that the sandstone near the granite is not normal, but altered, metamorphosed, and that in some places thin veins are separated from the granite, cutting into the sandstone layers. This will be enough to say that granite is younger than sandstone, and fossils in the latter will help determine the age of granite; for example, if they are Upper Devonian, then the granite will be younger than Devonian.

In another outcrop of the same area we will find the same granite in contact with a layer of sandstone, at first glance the same as in the previous case (Fig. 282); but a study of the contact will show that there are no veins of granite in the sandstone and that the sandstone is not altered, but near the contact contains small fragments and individual grains of granite. This proves that the granite is ancient: it not only hardened, but even as a result of erosion it came to the surface of the earth, and sandstone was deposited on its eroded slope (Fig. 283).

If the latter contains fossils, for example, of Lower Permian age, we will conclude that the granite is older than the Permian, and from the totality of both exposures we will establish that the granite intrusion occurred during the Carboniferous period and rather at the beginning than at the end, since for the erosion of the intrusion it is necessary allow sufficient time.

Study of the relief

Let us take for example the almost-plain, the decrepitude stage of the erosion cycle. In some places there are flat hills, the so-called residual mountains or outcrops; in some places there will be a bed of hard stones, here and there a smoothed outcropping of granite sticks out among the grass, or all the soil between the grass is strewn with its debris; the ravine exposes several eroded layers of limestone, sandstone or shale. The pathfinder-geologist will study all these, at first glance, unimportant documents, measure how the layers lie, where they stretch, in which direction they are tilted, determine the composition of all the outcrops, find fossils in them, determine the age of the layers and the sequence of past events, and plot his observations on map of the area and tell his unscientific companion (who helps him in his work) the whole history of this country: what mountains once stood on the site of this plain, what rocks they consisted of, where the mountain folds stretched, whether there were volcanoes on them or in the depths igneous massifs, when these mountains were formed and when they were destroyed. The pathfinder-geologist, studying traces - documents of previous events, unravels the history of the area where his companion walked for many years and did not know that he was trampling the last remnants of the Alpine mountains, passing unnoticed through the former high ridges and sitting calmly on the grass in the place where The molten lava of the volcano once bubbled.

The third task of the pathfinder-geologist, performed simultaneously with the first two, is to find and study minerals of all kinds that may be found among the rocks of the area under study. He must determine their quality, conditions of occurrence and, depending on these data, find out whether the found deposit deserves preliminary exploration, without which in many cases it is impossible to decide whether there is a sufficient amount of the mineral found in individual outcrops, i.e. whether it has practical significance. With good exposure, it is possible to resolve the question of the probable amount of the mineral in general terms based on observations on site and after studying and analyzing samples of the fossil in the laboratory; analysis will determine the percentage of ore or other mineral in a vein, deposit, or rock. If there is insufficient exposure, exploration is necessary - deepening pits, making more or less deep ditches on slopes or on the plain, drilling wells. This constitutes the task of preliminary exploration, in which in recent years, thanks to the invention of precise instruments, geophysical methods have begun to be used, based on the determination of magnetism, electrical conductivity, gravity and the propagation of seismic waves caused by explosions in various rocks and minerals.

When searching for minerals, you should pay attention to the remains of ancient ore workings - funnel-shaped pits, slot-shaped excavations, blocked shafts and adits, accumulations of ancient slag and foundry molds, etc.; Near such old mines one can find deposits from which ore was mined in prehistoric times.

Fossils, their collection and storage

Bones of land mammals are found in sediments on land or in lakes. Shells with thick valves live in shallow seas, where waves extend to the bottom, and shells with thin valves live at great depths. Fossil corals indicate the warmth of seawater, and some shellfish indicate its low temperature. Shark teeth are found only in marine sediments, and the shells of Paleozoic fish are found in sediments of river mouths, lagoons and shallow sea. Insect prints are known exclusively from continental sediments.

Marine sediments, especially shallower ones, are richer in fossils than continental ones, and their fauna is the most diverse; sponges, corals, sea lilies, stars, urchins, various mollusks, brachiopods, and crustaceans are found in abundance there. In the deepest sea sediments you can only find lower forms- various foraminifera, radiolarians and diatoms.

In continental sediments, plant remains are more common than animal remains; but in some places the latter are abundant, and the bones of vertebrates form whole layers, for example, in the Permian deposits on Northern Dvina, in the Triassic of the Kirov region, in Cretaceous and Tertiary deposits North America, Mongolia, Kazakhstan.

Of the sedimentary rocks, marls, bituminous and argillaceous limestones, calcareous and glauconitic sands, but often also sandstones and shales, most often contain fossils. Quartzites and quartz sandstones are usually very poor in organic remains; conglomerates can contain only large and hard remains that have withstood the friction and impacts of pebbles and boulders in the surf or in the stream bed, for example, the bones and teeth of vertebrates, thick shell valves, and plant trunks. Organic remains, especially of animals, often cause the formation of nodules, that is, concretions rich in lime and completely enveloping the fossil, which is revealed when the nodules are broken up. The latter contain ammonites and other mollusks, fish, bones of vertebrates, even their entire skeletons, around which the constriction gradually increased. Therefore, nodules in sedimentary rock layers must be broken up to discover whether they contain fossils. In intrusive rocks, of course, there are no organic remains; in volcanic rocks they are extremely rare, but in tuffs, especially fine-grained and clear-layered ones, very good imprints, mainly of plants, are sometimes found.

Fossils are found in rocks either separately, in single specimens, or individual layers are rich in them or even consist entirely of them. Such layers are formed, for example, from corals, algae, brachiopods, mollusks, bones and their fragments; corals make up entire fossil reefs, algae make up thick layers, shells make up shell jars. Plants most often form imprints in a thin layer of rock, which can be rich in them over its entire surface. The layers and interlayers of coal consist entirely of plant material, but it is transformed into a continuous mass, and individual forms (leaves, stems) are rarely distinguishable; but in the soil or roof of a coal seam there are often good imprints.

The remains of invertebrates represent the solid parts of their bodies - shells of mollusks and brachiopods, stems and arms of crinoids, shells and needles of urchins, shells of foraminifera and shells of crustaceans; the original material is replaced by carbonated lime, less often by silica, sometimes by sulfur pyrites, and the place occupied by the soft parts of the body is also filled with rock.

From mammals, their bones are preserved separately or in the form of whole skeletons; the shields of the shells of fish, reptiles, amphibians, teeth, their needles, horns and teeth of mammals are also preserved. Only in exceptional cases, in the perpetually frozen soil of Siberia and in asphalt, are soft parts of the body, entrails, and skin preserved.

Such finds are of particularly great scientific importance. They made it possible to recreate with complete accuracy the appearance of the hairy rhinoceros and mammoth, while numerous reconstructions of other higher animals made by different scientists are not so reliable; they were made on the basis of skeletons, often very incomplete, and without data on the nature and color of the skin.

The remains of animals can most easily be found on the weathered surface of rocks in outcrops and in screes at their feet, since they have a different composition and sometimes greater hardness than the rocks containing them, and therefore protrude somewhat during weathering and are released when the rock is destroyed. Therefore, the pathfinder-geologist first of all carefully examines the small weathering products in the screes, the surface of the blocks lying at the foot, and the surface of the outcrop itself. If the rock contains fauna, the latter will almost always be discovered during such an inspection. Only fossils collected in screes and individual blocks should not be mixed with those obtained from the outcrop itself, as they could have fallen out of different horizons the last one. During geological research, each outcrop receives a separate number in the description and on the map, and the layers of different rocks that make up it are designated by separate letters with the same number. Therefore, fauna collected in the outcrop itself will have a number with a letter corresponding to the layer from which it was taken, while fauna collected in the scree will have only one number.

Pebbles in the bed of a stream or river often represent rounded fossils and serve as an indication for searching for outcrops of the corresponding rock upstream.

Having discovered organic remains in an outcrop, they are extracted using a hammer and chisel, trying to turn out a large piece containing the remains, and then carefully split it into layers or chip it in the corners if the rock is not layered. Of course, you can’t hit the fossil itself with a hammer. It is better to take away a piece rich in residues entirely so that you can carefully process it at home at your leisure. In soft rocks, the fossils are carefully removed using a chisel along with the surrounding rock. When collecting, fossils taken from different layers of the same outcrop, much less those collected in different outcrops, should not be mixed with each other. You can't rely on memory; Each sample must immediately receive its number with a letter written in pencil on it or on a label, and must be wrapped in paper.

Vegetative impressions on the bedding planes of shale or sandstone mostly consist of a thin film of coal that falls off easily. Therefore, to carry and transport them, they must be covered with a layer of cotton wool and then wrapped in paper. Cotton wool is also used to protect fragile shells, small bones, insect prints, etc. It is better to collect small shells and other remains in boxes or cans, layering them with cotton wool and inserting a label with the number of the exposure and layer. Fossils, wrapped in paper, are taken home (or to the ranger's camp) in a backpack, duffel bag or shoulder bag (or in a simple bag or basket), then examined, neatly labeled with the exact location of collection, and stored in boxes. In order not to be confused when viewing and comparing, you need to write its number and letter on each sample with a chemical pencil or ink. To be sent by mail to another city, the samples, wrapped in cotton wool and paper, are packed in a box, placing them tightly next to each other.

It is best to place concretions in which the presence of fossils is suspected in the fire of a small fire, but do not heat them, but only heat them very much and then throw them into water or pour water on them; they fall apart, cracking along the surface of the fossil and releasing the latter. The bones of vertebrates are often enclosed in enormous nodules, which can only be obtained by special excavations and experienced people. Therefore, in the event of the discovery of such nodules, the pathfinder only accurately records and marks on the map their location in order to report it to the Academy of Sciences or the university, which can organize excavations. In other cases, such bones are enclosed in clay, loam, sand or sandstone, but in such a decayed state that they are destroyed when an attempt is made to extract them; an inexperienced tracker should also not mine them, but write down and mark the place on the map and report it, since the extraction of such remains requires special techniques and experience.

Pathfinder Equipment

The geological pathfinder's equipment consists of a hammer, chisel, mountain compass, notebook, magnifying glass, bag or net and a small supply of wrapping paper and cotton wool.

The hammer (if it is possible to get it) is the so-called geological one, in which one end of the head, the striker, is blunt, and the other is sharpened with a wedge across the handle or pointed with a pyramid, like a pick; the latter style is convenient for working in loose rocks, the first - in hard rocks. The hammer size should be medium, its head should weigh about 500 grams. If you don’t have a geological hammer, you can take a small blacksmith’s or wallpaper hammer; but to work in hard rocks, it is necessary that the hardening is not too soft, otherwise it will be flattened by impacts and will soon become unusable.

The chisel is a strip of steel with a round or rectangular cross-section, elongated at one end in the form of a sharp wedge; the iron chisel at the sharp end must be welded with steel. The length of the chisel is 12-15 centimeters, weight from 250 to 500 grams. A chisel is needed to knock out minerals and fossils, to break off pieces of rock; during operation, it is inserted with the end of the wedge into the crack and hit with a hammer on the blunt end.

A mountain compass differs from an ordinary pocket compass in that the box with a dial and a magnetic needle is attached to a brass or aluminum square or rectangular plate and that the signs B and 3 or O and W, i.e., east and west, are rearranged one in place of the other. The divisions on the dial go from 0 to 360° counterclockwise. In addition, under the arrow on its axis there is a weight with a pointer, and on the dial on both sides of the letter B (or O) there are further divisions from 0 to 90° to determine the angle of incidence of the layers. When buying a compass, you need to make sure whether the arrow has a clamp in the form of a screw outside the box (which should press the arrow to the glass when carrying the compass in your pocket), whether it operates freely, whether the arrow swings well, gradually reducing its swing. The compass box should have a brass or aluminum lid. It is good if the compass has a case made of leather or strong material. Currently, there are compasses made of plastic.

A pocket magnifying glass is useful for viewing fine-grained rocks, fossils and minerals; magnifying glasses come in metal, horn or bone frames; The magnification is preferably about five times.

A notebook with a pencil - for recording observations, preferably with squared paper for sketching outcrops.

The bag is needed to carry collected specimens, provisions for long excursions, and a supply of paper and cotton wool. The duffel bag (backpack) is spacious and does not interfere with work, but it must be removed to take out and put in something. Nets used by hunters to place killed game, or field bags on a belt, are also good.

Paper and cotton wool are required for wrapping rock and fossil specimens, labeled with a number to ensure they are not mixed up when being transported.

For loose and crumbling rocks, you need to have several small bags that can be easily glued together from paper. It’s even better to prepare yourself such bags from canvas or calico, 10 centimeters wide, 15-16 centimeters long, with twine ties, 20-30 pieces, number them in order with a chemical pencil and put the collected rock samples in them in the order of collection, marking V notebook only the number of the bag containing the sample from a given outcrop. This eliminates the need to wrap the sample in paper and write a label in the field. All these operations are done at home, when sorting out the collected collection, and the bags are freed for the next excursion.

It is very useful to keep a diary, setting out in more detail (in ink in a notebook) all the observations made during the excursion. In the field, you can write them down in a notebook quickly, briefly, when sketching outcrops. At home, for fresh memory, all the details will be outlined and the drawing drawn up carefully, with coloring with colored pencils.

The size of the samples can be very different, from 3X5 to 7X10 centimeters (width and length; thickness depends on the quality of the rock, but generally no more than width). A young tracker can limit himself to small ones. It is necessary that the sample be chipped on several sides, that is, it has fresh fractures and not a weathered surface. Fossils, of course, cannot be crushed. To store collections, you need to create flat cardboard boxes according to the size of the samples.

You should have a penknife in your pocket for sharpening a pencil and testing the hardness of minerals and rocks. It doesn’t hurt to have at least a small tape measure with a 1 meter long tape to measure the thickness of layers and veins.

If possible, purchase a good topographic map of the area. It will be very useful for orientation, choosing routes and plotting the examined outcrops on it. The map needs to be pasted onto canvas or calico, cut into pocket-sized pieces, since a paper map folded into this format will soon wear out on the folds when carried in a pocket. The card must be very protected from dampness, and once wet, carefully dry and smooth it.

A portable camera is useful to have with you for photographing terrain and outcrops in addition to describing them.

In conclusion, we will indicate how to determine the conditions of occurrence of sedimentary rocks using a compass. With its inclined position, each layer has a known strike and dips in one direction or another at a certain angle; measurements of the strike line, direction and angle of incidence determine the burial conditions. You need to select a flat area on the bedding plane of one of the strata in the outcrop and apply the compass to it with the long side of its board in a horizontal position; By drawing a line with a pencil along the edge of the board, we get the strike line AB. Having lowered the clamp of the compass needle and waited until it calms down, we record the reading of one of its ends. Let's assume that one end shows NE (NO) 40°, and the other SW (SW) 220°. The strike line therefore has an azimuth of NE 40° or SW 220°; They prefer to write down northern directions for consistency. Now let’s turn the compass board by 90°, i.e., put its narrow side to the line of strike, but so that the northern end of the board, i.e., the part of the limb where the sign C (N) stands, is directed in that direction, towards which the layer is inclined. Let us record the reading of the northern end of the arrow, and not the southern one. Let it be NW (NW) 310°; The formation, extending from southwest to northeast, dips to the northwest. The dip azimuth should always differ by 90° from the strike azimuth, since the dip line is perpendicular to the strike line (Fig. 285).

Now let's turn the compass board on its side and place it vertically with its long side to the line of incidence of the VG; a weight rotating around the arrow axis will show us the angle of inclination, i.e., the dip of the formation, for example 32°. We write the measurement results as follows:

Simple NE (NO) 40°; pad. NW (NW) Z 32°.

We do not write down the dip azimuth, since it differs by 90° from the strike azimuth. Therefore, you can limit yourself to recording one fall, but then you need to write its azimuth, i.e. NW (NW) 310° Z 32°. This record fully determines that the strike will be NE (NO) 40°.

If the pathfinder has only an ordinary pocket compass in a round box, then he can determine the strike and fall only approximately, by eye, by comparing in which direction the strike line deviates from the north-south line of the compass, with which the arrow should coincide, and in which direction the layer is inclined. The angle of incidence will also be determined by eye.

The strike and fall of veins and cracks are measured separately, just like for strata, on a flat area. If the latter is not present, the measurement is made by eye in the air and, of course, not so accurately.

We are finishing our book, in which we tried to show the reader the interest and practical significance of Earth science, as well as explain what and how can be observed on the vast territory of our homeland, with some preparation and the simplest instruments. The natural conditions of the USSR are so diverse that a young explorer living in any area will find around him enough material to observe the composition and structure of the Earth and its relationship with modern relief. He may discover and collect fossils, describe interesting outcrops, look for signs of minerals, and become an expert in the immediate vicinity of his place of residence. Helping him in this work, introducing him to the basics of geology, was the purpose of this book. And to further deepen and expand geological knowledge, the following guides and manuals can be recommended to young explorers.