Minerals of the World Ocean (main types of solid minerals): Textbook. Solid minerals of the shelf and the world ocean located in the zone of interests of Russia

The extraction of solid minerals from the World Ocean largely depends on the development and establishment of marine geology and marine mining.

Until now, it was concentrated in the shelf zone at a depth of up to 200 m, i.e., it gravitated towards land and practically developed in the same ways as in continental developments.

Offshore deposits have been identified as part of land deposits, as their natural extension into the sea (for example, platinum in the USA, cassiterite in Indonesia). In a number of cases, the geological situation on land favored the discovery of deposits in the adjacent shelf zone (diamonds in Namibia, ferruginous sands in Japan). Some deposits in Canada, Japan, England, etc. are known for their known outcrops of fossil layers on the shore, which were traced under the seabed.

Coal, iron ores, tin, and sulfur are extracted from the primary deposits of the seabed. Mines and mines under the seabed have extensive network mining workings. In Japan, more than 30% of coal is mined from such mines, in England - 10%. One of the largest high-productivity iron ore enterprises in the world is the Canadian Wabana mine, opened by inclined workings from Bell Island.

In the beach and coastal-marine zones, placer deposits of tin, gold, platinum, rare earth elements, and ferruginous sands are already being developed. Thus, in capitalist countries, about 100% (of the total production) of zirconium and rutile, about 80% of ilmenite, and more than 50% of cassiterite are obtained from underwater placer deposits. Extraction of building materials (wood, gravel, shell rock) in the coastal zone using modern technology allows us to obtain high-quality raw materials at an acceptable cost.

The shelf zone - relatively accessible in technical terms - occupies one fifth of the area of the continents. Structurally, it is a continuation of the continental platforms below sea level. The probability of discovering deposits of solid minerals in sedimentary and bedrock of the shelf floor is the same as in continental conditions. This is an important circumstance: in our country, the shelves occupy an area of about 6 million km 8 (21.8% of the total shelf area in the World Ocean).

Recently, foreign countries have attached particular importance to the development of deep-sea ore deposits discovered in central regions oceans and in some faults earth's crust at the bottom of seas and oceans. Deposits suitable for development contain on average up to 2% nickel, cobalt and copper, about 20% manganese, as well as a number of other valuable elements. The average density of nodules in promising areas reaches 10 kg per 1 m 3 of bottom area. According to rough estimates, profitable production can be ensured by an enterprise that annually produces 3 million tons of dry nodules.

The identification and development of solid mineral deposits, especially in open parts of the World Ocean, faces a lack of experience in offshore mining. The insufficient efficiency of offshore mining carried out using traditional equipment used in continental conditions is the main obstacle to the deployment of offshore mining. Analysis of global experience in offshore mining, modern technical means and technologies, and trends in their improvement is a pressing task.

Currently, billions of tons of minerals are mined annually around the globe. With the current volume of extraction of mineral resources from the bowels of the Earth, confined to land, it may be enough, according to the definition of a number of experts, only for the first hundreds of years, and for some minerals - only for the first tens of years. The depletion of reserves leads to the involvement in the development of increasingly poor mineral deposits with complex mining, geological and hydrological conditions, and the development of deposits in remote and uninhabited areas with unfavorable climatic and meteorological conditions.

At the same time, 2/3 of the earth's surface is covered by seas and oceans, on the bottom and in the waters of which a large amount of mineral reserves are concentrated. The world's oceans are a great potential source for obtaining minerals, both through their direct extraction from sea water, and mainly through the extraction of minerals in vast territories covered by seas and oceans.

Long before our era, edible salt was mined on the coasts of the seas and oceans; amber from the beaches of the Baltic states was famous for many centuries; oil and gas have been extracted from the bottom of the seas and oceans for more than 100 years. However, only in recent decades, in connection with the general development of science and technology, serious prospects for the extraction of solid minerals by the floating method began to emerge. The interest in minerals of the seas and oceans these days is not accidental:
many land deposits are being depleted;
the rapid growth of the world's population, and with it the need for the production of means of production and consumer goods, forces us to look for new sources of mineral raw materials;
the giant leap in the development of science and technology in recent years makes it possible to reach and develop the previously inaccessible riches of the seas and oceans;
the extraction of some types of minerals lying on the seabed is more economically profitable than on land.
The economic feasibility of underwater mining is ensured by a number of advantages:
there is no need for land alienation and subsequent reclamation;
when developing underwater fields, no access roads are needed;
many of these deposits do not require the installation of dumps and various types of storage facilities;
the costs of opening the deposit are significantly reduced;
there is no need to carry out large, labor-intensive and expensive blasting operations, or spend money on purchasing explosives, complex equipment, etc.

Subsea mining- development of mineral resources on the bottom of rivers, lakes, seas and oceans. Underwater mining is the extraction of minerals from an underwater face to the surface by a complex of mechanisms and equipment operating in an aquatic environment in order to obtain, process and use the main and associated components of the deposit. Underwater mining is carried out by open (dredges and dredgers) and underground (mining under the seabed and boreholes) methods. Conventionally, underwater mining includes the extraction of useful components from sea water (physical and chemical separation of salts and chemical elements).

In open-pit underwater mining, the following production processes are distinguished: 1) separation of the extracted raw materials from the deposit mass; 2) delivery from the intake mechanism to a floating or stationary facility (ship, barge, pontoon, platform); 3) primary processing of raw materials (screening, separation, washing, etc.); 4) storage and transportation for subsequent processing. The first stage is carried out by mechanical, hydraulic, pneumatic methods or a combination of them. With the mechanical method, bulldozer shovels, augers, grabs, buckets, etc. are used; with the hydraulic and pneumatic method, hydraulic monitors, erosion nozzles, siphons, and pumps are used. The work of the second stage is carried out using grabs, bucket chains, screw and belt conveyors, pressure pumps, air lifts, and ejectors. The third stage is associated with the operation of screens, hydrocyclones, and separators. At the fourth stage, storage facilities are needed, as well as means of transport (ships, barges, pipelines). Depending on the mining, geological and hydrometeorological conditions, the depth of development and the type of mineral, various technical means are used, as well as underwater mining methods. The predominant factor is the depth of the sea. Prey is distinguished: shallow water with a water depth of no more than 5 - 10 m; within the shelf with a depth of up to 100 - 200 m; over 200 m to the extreme depths of the ocean (sea). In the first two zones they mine: building materials, precious stones and metals, polymetallic and iron-containing sands, raw materials for the chemical industry, and energy raw materials. The third zone is promising for the extraction of nodules, oil and gas.

Placers are mined primarily using multi-bucket, hydraulic and clamshell dredges. To develop ferromanganese nodules, dredges with hydraulic lift (air lift) and buckets attached to an endless cable were tested and built (1974) (Fig. 16.4.).
In the Leningrad region, manganese mining began from the bottom of the Gulf of Finland. Promtrak LLC, which is leading the development, plans to provide 5-7% of Russia's demand for manganese, currently imported from the CIS countries and non-CIS countries. The plant was built in the industrial zone of the city of Kingisepp. Pilot industrial operation is currently underway.

There are no large deposits of manganese in Russia; up to 90% of this metal is purchased abroad. The nearest deposits are in Georgia, Kazakhstan and Ukraine. But huge reserves of manganese are found at the bottom of the seas and oceans (most of it is in the Pacific and Indian oceans).
Of great interest are sources rich in various elements - hot underwater geysers, or “black smokers” (Fig. 16.5.).

In them, sea water first seeps through cracks to great depths, where it heats up to several hundred degrees, becomes enriched in minerals and rushes up, carrying a thick suspension rich in minerals, which is carried by the current and settles in the surrounding area. This is how kilometer-long hills rich in metals arise (Fig. 16.6.). The extraction of such minerals is carried out in the same way as the mining of placers (Fig. 16.4.).

In underwater underground mining, the production processes are similar to the processes of underground mining of mineral resources confined to land. In most underwater mines, shafts are laid on land, as a result of which the haulage workings have a length of up to 10 km. Opening of mine fields with shafts from artificial islands is used (for example, the Maike mine, Japan). The depth of the mine workings under the bottom, which guarantees them from flooding, depends on the properties of the overlying rocks and is usually equal to 65 - 80 m. Deposit development is carried out with the filling of the mined-out space. Coal is mined this way in Japan, Canada, England, Scotland, Turkey, China and on the island of Taiwan.

Most often, offshore deposits are a continuation hidden in the bowels of the land.
Extraction from underwater mines of iron ore is well developed, which is carried out in Japan on the island of Kyushu, in Australia, in Canada in Hudson Bay and on the island of Newfoundland (an artificial island was built here to extract ore), as well as in Finland, at the entrance to the Gulf of Finland.

Much less common are underwater mines where ores of copper and nickel, tin and mercury are mined. In Canada, in Hudson Bay, near the city of Churchill, copper and nickel are mined, in Great Britain, on the Cornwall peninsula, copper, nickel, and tin are mined.

In Turkey, mercury ore deposits are being developed under the bottom of the Aegean Sea.
Underwater mining also includes the extraction of minerals from sea water, based on the physical and chemical processes of separating salts and various chemical elements dissolved in it, the total volume of which reaches 48 million km3 (including about 2x1016 tons of sodium, about 2x1015 tons magnesium, about 1.3x1014 t bromine).

From the middle of the 19th century. from mother brines table salt in France they began to obtain bromine. Since the 30s. 20th century Industrial extraction of magnesium from sea water has begun. In 1970, in the USSR, USA, Great Britain and other countries, there were over 100 enterprises for the extraction of sodium chloride from sea water with a production volume of over 10 million tons, magnesium 300 thousand tons, and bromine 75 thousand tons.

The technology for extracting chemical elements from sea water involves, as a rule, their concentration, and then, when the saturated solution interacts with other elements, their production in the form of compounds (Fig. 16.7.)

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In addition to the surface of the continents, man throughout his history has used the minerals of the ocean and sea.

Until recently main area Fishing has been exploited, but in recent decades an important role in the economy of some coastal states has been played by the seabed in the area of the continental margins.

Man uses salts dissolved in sea water. Nowadays, the reserves of the sea are often spoken of as the hope of humanity. The seas and oceans, covering more than two-thirds of the surface of the globe, are called upon to maintain the energy, raw materials and food balance of the increasing population of the Earth.

Naturally, the question arises, is this real?

What can be obtained from the World Ocean

It would seem self-evident that the salt that humans consume comes from the sea, but this is not so.

Only a third of table salt is obtained by evaporation of sea water, the rest is mined on continents or by evaporation of brine - mineralized waters accompanying salt deposits.

So, sea water is a chemical raw material, but the most valuable thing that is obtained from it is not salt, but bromine, used primarily in the photographic industry, and magnesium. More than two-thirds of the world's consumption of these elements is obtained from seawater.

Ocean bromine mining

Sea water also contains a number of other compounds that are in a dissolved state. From time to time in the media you can read how much uranium or gold it contains. These numbers are truly amazing.

However, we are limited in our actions by the fact that we do not yet have sufficient quantity energy to establish the process of their extraction. But nature itself carries out a number of processes for humans.

Extraction of heavy metals from the seabed

For example, copper, manganese, cobalt, and nickel do not need to be extracted from sea water, since these metals precipitate and crystallize at the bottom of ocean basins in the form of manganese nodules. These are formations the size of a nut, a fist or a football, scattered in abundance along the bottom of the Pacific and Atlantic oceans and consisting of layers of iron and manganese oxides, the crystalline structure of which easily binds more heavy metals, like nickel, cobalt and copper.

The total content of ocean minerals in the form of metals in manganese nodules reaches 2.5%. Therefore, research ships map the seabed, photograph it using underwater cameras, and scientists analyze the metal content in these spherical formations.

The detected metal content is still low, and the costs of extracting raw materials from the bottom are high. But there are hopes for sources of raw materials, although people have difficulty agreeing on the legal side of the issue of extraction from the bottom of the sea.

The extraction of so-called heavy minerals in coastal areas has been carried out with great success.

For example, scientists found an underwater mountain 300 miles off the coast of the Canary Islands. The mountain represents the rare earth metal tellurium.

The cost of this metal is about $300 per kg, which will be quite profitable to start mining from the seabed.

Water sorts minerals

Medieval miners, and even later gold miners, obtained gold by washing river sediments. The water carried away lighter silicate minerals from the prospecting sieves, leaving heavier minerals at the bottom. When lucky, then pieces of gold.

The sea surf and strong sea currents in some places did this work for a person.

Heavier minerals such as cassiterite (tin ore), zircon (zirconium ore), rutile (titanium oxide), monazite (a complex phosphate containing rare earth elements) and even diamond are released from rocks during weathering, and since they are more persistent, than many other minerals (such as feldspar), water carries them out to sea. There they are sorted as in a prospecting sieve: the lighter, usually silicate and quartz materials are carried away, and the heavier, useful fractions remain on the beach or on the shallow seabed. In many places in the world, minerals are mined in transition zones from the ocean to the continents.

However, ocean and sea minerals are still difficult to extract or extract from the seabed for profit. But technology is improving and perhaps the main ones will be at sea.

Edition: Moscow State University Publishing House, Moscow, 2000, 160 pp., UDC: 553.3, ISBN: 5-211-04346-4

Language(s) Russian

The textbook provides characteristics of the most important geological and industrial types of ore and non-metallic deposits of the ocean, both actively being developed at the present time, and promising ones, the industrial development of which is planned in the future. Information is provided on the geology and metallogeny of the ocean, the patterns of distribution and localization of deposits. The processes of modern ore genesis are considered; the main attention is paid to the formation of ferromanganese nodules and crusts, sulfide-bearing sediments and massive sulfide ores.

For students and undergraduates of geological universities and specialists in the field of marine geology and ore deposits.

The ever-increasing need for various types of mineral raw materials and the depletion of mineral reserves on land make the problem of studying and developing the mineral resources of the bottom of the World Ocean a priority. In recent decades, targeted searches for various types of mineral raw materials have been carried out throughout the vast ocean area. Judging by the forecasts of domestic and foreign experts, the share of offshore mineral deposits in the third millennium will become predominant compared to onshore deposits. Many states that have the largest resources of solid minerals in zones of special economic interests and in intensively explored areas of the International Seabed Region - primarily the USA, France, Russia, Japan, China, India, the Republic of Korea and others - are actively preparing for the start of development offshore fields.

The current level of study of marine mineral formations allows us to distinguish the following groups of solid minerals: 1) ferromanganese (polymetallic) nodules; 2) cobalt-rich ferromanganese crusts; 3) massive sulfides; 4) metalliferous sediments; 5) phosphorites; 6) placers (tin-bearing, gold, titanium-zirconium, diamond-bearing, etc.); 7) hydrocarbons in the solid phase - gas hydrates; 8) building materials (sand, gravel, shell rock). This textbook has been compiled in accordance with the course programs “Ore Deposits” and “Mineral Resources of the World Ocean”, provided for by the curricula of geological departments of universities and geological exploration universities. Contains characteristics of promising geological and industrial types of solid ocean mineral deposits. Information is provided on the history of discovery and study, the prevalence of each type of minerals, mineral and chemical composition ores, genesis, prospects for industrial development. When compiling the manual, extensive literary material and the results of the authors’ personal research were used.

Introduction

1. Geological structure of the ocean floor

3. Solid minerals of the World Ocean

4. Mineral resources of the World Ocean and the possibilities of their development

Conclusion

Bibliography

Application

Introduction

The relevance of research. As mineral resources on land become depleted, their extraction from the ocean will become more and more important, since the ocean floor is a colossal, almost untouched storehouse. Some minerals lie openly on the surface of the seabed, sometimes almost close to the shore or at relatively shallow depths. Naturally, such deposits begin to be developed first, since only slightly modernized conventional equipment can be used here.

In a number developed countries reserves of ore, mineral fuels and some types of building materials have become so depleted that they have to be imported. Huge ore carriers ply across all oceans, transporting purchased ore and coal from one continent to another. Oil is transported in tankers and supertankers. Meanwhile, there are often sources of mineral resources very close by, but they are hidden under a layer of ocean water.

Various building materials - sand, gravel, crushed stone - are of great interest for industrial mining in the shelf zone. As a rule, they are of high quality, because nature itself took care of sorting them according to the sizes of the constituent particles. The reserves of this kind of building materials in the shelf zone are almost unlimited, and therefore many coastal countries are mining them. In the United States alone, 0.5 billion tons of sand and gravel are obtained from the sea annually for construction needs. Transportation to shore or loading of material onto barges is carried out through pipes mixed with water, so its cost is relatively low.

In some warm seas, huge areas of soil consist of layers of shells of small bivalves. This is almost pure lime, suitable for use in construction, but it is mainly used to feed poultry. Large reserves of broken shells are available in the Sea of Azov. Every year, thousands of tons of this valuable material are sent from here to the country's poultry farms. It is interesting that the reserves of “shells” practically do not decrease - the shells of the dead generation of mollusks make up for the damage caused.

Closer to the outer edge of the shelf, nodules containing large amounts of phosphorus have been found in many parts of the world's oceans. Their reserves have not yet been fully explored and calculated, but, according to some data, they are quite large. Thus, off the coast of California there is a deposit of about 60 million tons. Although the phosphorus content in the nodules is only 20-30 percent, its extraction from the seabed is quite economically profitable. Phosphates have also been found on the tops of some seamounts in the Pacific Ocean. The main purpose of extracting this mineral from the sea is to produce fertilizers; but, in addition, it is also used in the chemical industry. Phosphates also contain a number of rare metals as impurities, in particular zirconium.

In some areas of the shelf, the seabed is covered with green “sand” - an aqueous oxide of iron and potassium silicates, known in mineralogy as glauconite. This valuable material is used in the chemical industry, where potash and potash fertilizers are obtained from it. Glauconite also contains rubidium, lithium and boron in small quantities.

The purpose of the work is to analyze the minerals of the World Ocean.

To achieve the goal, it is necessary to solve the following tasks:

1. Consider the geological structure of the bottom of the World Ocean.

2. Consider oil and gas bearing areas of the World Ocean.

3. Characterize the solid fossils of the World Ocean.

4. Analyze the mineral resources of the World Ocean and the possibilities of their development.

The object of study is the mineral resources of the World Ocean.

The subject of the research is the minerals of the World Ocean.

1. Geological structure of the ocean floor

By the word “earth” we usually mean land, and not the vast waters of the oceans, although they occupy 70.8% of the surface of the entire planet. It has long been known that the oceans are water basins that fill the huge depressions of our planet, and the land - the continents - are the largest rises of the earth's surface, like islands among the oceans. There are almost no “white spots” on the land map anymore. But the underwater spaces of the Earth, hidden by the surface of the ocean, still keep many secrets.

As has been established, the geological structure of the ocean floor is very complex and differs in many ways from continental land. Meanwhile, if you do not know the geological structure of the bottom of the World Ocean, you cannot imagine the structure of the Earth as a whole, you cannot understand the laws of its geological development. Do people need this? Is there a practical need to penetrate the secrets of the ocean floor?

People have long been interested in how the ocean floor works. First of all, sailors needed to know what awaited the ship on the open sea: enormous depths or dangerous rocky shoals - this was the question everyone who set off on a voyage asked themselves. As navigation technology developed, interest in the ocean increased. Sailors learned to measure ocean depths and by the nature of their changes, even roughly determine the location of the ship. So, if the depths began to decrease sharply, ship captains expected the shore to approach. The advent of submarines increased the interest of sailors in the structure of the seabed at much greater depths. Fishermen also began to take an interest in the structure of the bottom: usually cod, halibut, flounder and other commercial fish gather at the edges of the shallows, the tops of underwater hills and some parts of the slopes; there they catch it with trawls. At the same time, it is important for fishermen to know the nature of the soil so as not to touch rocks and boulders - this can tear or even completely tear off the trawl or clog the trawl net with silt. But even if fishermen do not catch bottom fish, but those floating near the surface or in the water column - herring, saury, tuna, then they are also not uninterested in the structure of the ocean bottom. It turns out that these fish often stay above banks (shallows) and the tops of seamounts, because the upward movements of deep ocean waters over the slopes of such landforms bring up salts that contribute to the development of plankton, which the fish feed on.

Geologists also became interested in the seabed. Deposits of oil and natural gas at the bottom of the Caspian Sea, in the Gulf of Mexico and in the North Sea, placers of manganese, copper and phosphate ores in the Pacific Ocean - all this has been discovered in quantities that cannot be compared with the mineral wealth of the land in many countries of the world. And one more reason forces geologists to explore the bottom of the oceans: the mineral wealth on the surface of the land is decreasing every day - we are using it up very intensively. There are still a lot of them in the depths of the Earth, but searching there is difficult and expensive. The search for minerals in the depths of the continental land will be much easier if you know the laws of the geological development of the earth's crust. Vast expanses of land in the past were occupied by seas and oceans, and they developed according to the same laws that govern the development of the bottom of modern seas and oceans. By studying the bottom, we will find the key to understanding the geological past of the continents, their deep structure and, consequently, the key to underground storehouses of minerals that will be used for the benefit of man.

So it turns out that it is necessary to know the geography and geology of the underwater world in order to better use the natural conditions and riches of the World Ocean and the Earth as a whole for the benefit of man. Therefore, the waters of the oceans are now plied not only by cargo and passenger, fishing and military ships, but also by research vessels measuring the depths of the ocean and studying the geological structure of its bottom.

The topography of the bottom of the World Ocean, as well as the topography of the land, was formed throughout the entire geological history of the globe. Its general character was created in the process of changing the Earth's surface under the influence of vertical and horizontal movements of the earth's crust, its uplifting in one place and lowering in another, as well as under the influence of volcanic activity and earthquakes.

As shown by numerous depth measurements made in various places The world's oceans, the relief of its bottom by its nature has many common features with land relief. The topography of the bottom of the World Ocean, as well as the topography of the land, is characterized by mountain ranges and individual hills, high flat-topped plateaus with steep slopes, pointed peaks and vast plateaus, huge basins, narrow and elongated valleys, gorges and deep depressions. Moreover, the depth of the ocean depressions significantly exceeds the height of the highest mountains on land. For example, the depth of the deepest currently known Mariana Trench in the Pacific Ocean is more than 11,000 m, while on land the height of the deepest high mountain Everest is only 8882 m.

The topography of the bottom of the World Ocean is subject to constant change. Currents and waves erode high places and destroy shores, smoothing out their outlines and transporting this eroded material to other places on the coast and to low areas of the ocean, gradually filling them. At the same time, under the influence of volcanic underwater eruptions and earthquakes, new relief forms are created on the ocean floor in the form of cone-shaped rises or deep depressions.

The bottom topography of the continental shallows is generally flat and calm. It has individual low, rounded hills forming shallows called banks, as well as shallow hollows and trenches. In some areas on the continental shallows, due to the activity of certain living organisms - corals and calcareous algae - complex fantastic relief formations are created, which often rise above the ocean level in the form of islands. Coral formations hidden under water or exposed when water levels drop are called coral reefs.

Coral islands and reefs are characteristic of continental shallows in tropical and subtropical latitudes, where the water temperature is not lower than 20 all year round, i.e. such as is necessary for the development of corals. Sometimes coral reefs stretch for many kilometers along the coast, forming barriers. For example, the Great Barrier Reef off the northeastern coast of Australia stretches for 2000 km, the barrier reef off New Caledonia has a length of 1500 km.

Often, in places where rivers flow into the ocean and in other places on the continental shallows and on the continental slope, there are valleys left behind by rivers that flowed here in the past, or that arose as a result of tectonic processes. These submarine valleys, like mountain slopes on land, dissect the continental shelf and continental slope with deeply incised gorges called canyons. Underwater canyons look like narrow and deep gorges with very steep slopes.

On the bed of the World Ocean stretch high and long mountain ranges, similar to the Cordillera or Hades mountain ranges, huge basins, individual plateaus and pointed peaks, narrow hollows and deep-sea depressions. There are currently 18 deep-sea depressions in the World Ocean; they are mainly concentrated in the oceanic hemisphere, most of which is occupied by the Pacific Ocean.

Geological activity of the World Ocean. Mineral resources of the ocean floor.

The water shell of the Earth covers almost 71% of its surface (362 million km2), which is 2.5 times more than the land area (149 million km2 or 29%), so our planet can be called oceanic. The volume of water in the oceans and seas is estimated at a gigantic figure of 1.4 billion km 3, while the entire hydrosphere is 1.8 billion km 3. The distribution of ocean areas is such that in the northern hemisphere, considered continental, land occupies 39.3%, and oceans 60.7%. In the southern, oceanic hemisphere, 19.1% and 80.9%, respectively.

The geological activity of the oceans and seas is carried out by different processes:

· abrasion (“abrado” - scrape off, lat.), destruction of coastlines by waves, tides, currents;

· transport of various materials carried out by rivers formed due to volcanism, aeolian (wind) activity, carried by ice, as well as dissolved matter;

· accumulation or deposition of sediments: biogenic, hydrogenous (evaporites, iron-manganese nodules), clastic and cosmogenic (spherules);

· transformation of sediments into rocks or diagenesis and redeposition of sediments. Before considering geological processes in the oceans and seas, it is necessary to say something about the properties of the water mass itself and its movement under the influence of various forces.

2. Oil and gas bearing areas of the World Ocean

One of the most pressing and pressing problems at the present time is meeting the ever-increasing needs of many countries in the world with fuel and energy resources. By the middle of the 20th century. their traditional types - coal and wood fuel - gave way to oil and then gas, which became not only the main sources of energy, but also the most important raw material for the chemical industry. For 20 years, from 1950 to 1970, world oil consumption increased 4 times, and natural gas 5 times. In the global energy balance, the share of oil and gas reached 64%, including in all developed countries it exceeded 75%, of which Western European countries accounted for 67% in 2000, and the United States accounted for about 80%. However, not all areas of the globe are equally endowed with these minerals.

Most industrialized countries meet their needs by importing oil. Even the United States, one of the largest oil producing countries (about a third of its global production), covers more than 40% of its deficit with imported oil.

Japan, the second-largest oil-using country, produces negligibly little of it, but purchases almost 17% of the oil entering the world market. Western European countries import up to 96% of their oil consumption, and their demand for it continues to grow.

TO beginning of XXI V. The leading place in the energy sector belongs to oil, gas and partly coal, despite intensive development and success nuclear energy. This will entail a noticeable decrease in fossil fuel reserves, since their renewal requires many thousands of years. Currently, there are quite contradictory estimates of the world's oil and gas resources and the rate of their consumption, and all of them are indicative. Usually, with an increase in the production of these minerals, their proven reserves in the world as a whole increase proportionally, but in developed countries, oil production, for example, outpaces the growth of its proven reserves. In addition, oil and gas consumption is largely determined by market conditions, so it changes noticeably from year to year, sometimes over several years. Finally, the lack of domestic oil and gas and the desire to reduce dependence on their imports stimulates many countries to expand the search for new oil and gas deposits. The development and generalization of the results of geological exploration over the past 20-30 years have convincingly shown that the main source of production of several tens of billions of tons of oil and trillions of cubic meters of gas can be the bottom of the World Ocean.

According to modern concepts, oil and gas in the bowels of the Earth are created as a result of the transformation of scattered organic matter, characteristic of subaqueous sediment. At the same time, a necessary geological condition for such a transformation is the existence of large-sized sedimentary strata in the areas of formation and accumulation of oil and gas. They form large oil and gas sedimentary basins, which are integral autonomous systems, where the processes of oil and gas formation and oil and gas accumulation occur. Offshore oil and gas fields are located within these basins, most of the area of which is located in the underwater depths of the oceans and seas. Planetary combinations of sedimentary basins represent the main belts of oil and gas formation and oil and gas accumulation of the Earth (GPA), divided into three main types: epigeosynclinal, pericratonic (marginal) and perioceanic. Geologists have established that in the gas oil reserve there is a complex of natural preconditions favorable for the development of large-scale processes of oil and gas formation and oil and gas accumulation.

It is no coincidence that out of 284 large accumulations of hydrocarbons known on Earth, 212 with reserves of over 70 million tons were discovered within the gas reserves, extending across continents, islands, oceans and seas. However, significant oil and gas deposits are distributed unevenly between individual belts, which is explained by differences in geological conditions in specific gas fields.

In total, about 400 oil and gas basins are known in the world. Of these, approximately half continue from the continents to the shelf, then to the continental slope and, less often, to abyssal depths. The confinement of sedimentary basins to areas of junction of continental and oceanic structures allows us to state the dependence of the number of underwater basins in a particular area of the World Ocean on the length of the coastline.

Offshore oil fields have been characterized by high rates of growth in production volumes over the past decade and a half. Offshore oil development currently covers about 350 fields located in different areas of the World Ocean.

A significant feature of modern offshore oil fields is their location within the shelf. Oil production is carried out mainly to depths of 200 meters.

Currently, several major underwater oil development centers have emerged, which now determine the level of oil production in the World Ocean. The main one is the Persian Gulf. Its depths contain 12-13 billion tons of recoverable oil reserves and 3.6-3.9 trillion. m3 of natural gas. Somewhat more than 200 million tons of oil and 42.0 billion m3 of gas were extracted here, which is equal to 40 and 25% of their global offshore production per year, respectively.

The second largest production area is the Gulf of Venezuela and the Maracaibo Lagoon. Its oil reserves in 2005 were estimated at 1.5 billion tons, and annual production was more than 100 million tons.

The Gulf of Mexico has large reserves of oil (410 million tons) and gas (1030 billion m3), where more than 50 million tons of oil and 115 billion m3 of gas are extracted per year.

The Gulf of Guinea is rich in oil, whose reserves are estimated at 1.4 billion tons, and annual production is 50 million tons.

The North Sea has relatively recently become an important oil and gas production area, the reserves of which are currently estimated at 3-7 billion tons. In 2006 year. 30 million tons of oil were produced here.

Other, quite numerous oil and gas bearing areas of the World Ocean with smaller reserves and production volumes are of significant interest to those countries that are producing.

The largest areas of oil and gas production from underwater subsoil - the Persian, Venezuelan-Maracaiba and Guinea - are located off the coast of developing countries that supply oil and gas to the world market. Only the Mexican and North Sea regions are located off the coasts of developed countries - large consumers of liquid and gaseous fuels. For some European countries (Great Britain, Norway, etc.), oil and gas production from the bottom of the North Sea has become a significant stimulus for industrial growth.

Currently, many countries, including those where oil and gas production from underwater subsoil is highly developed, are exploring new oil and gas-bearing waters.

The area of the oceans and seas that is promising for oil and gas is approximately 60-80 million km2, including about 13 million km2 in areas with depths of up to 200 meters, which is almost half of the entire shelf area of the World Ocean. The predicted geological reserves of hydrocarbons in the sedimentary strata of the oceans and seas, according to Soviet and foreign experts, reach 60-70% of the global total. In the depths of the bottom of the World Ocean (excluding areas of the territorial waters of socialist countries) 550 billion tons of oil and 260 trillion. m3 of gas, from which, at the current level of production technology (excluding cost), about 230 billion tons of oil can be extracted, 200 trillion. m3 of gas. Moreover, more than 60% of the possibly recoverable amount of oil and gas falls on the shelf. The possibilities of oil and gas accumulation in sedimentary rocks at the foot of continents, where geological conditions are favorable for the generation of hydrocarbons, have not yet been taken into account.

The main element of oil exploration and production is drilling. At sea it is carried out either from peculiar hydraulic structures- stationary bases for drilling rigs, or from mobile drilling rigs. Foundations in the form of steel structures are widespread. At the first stages, they were installed in the sea on metal piles driven into the bottom at depths of up to 20-30 meters. They were completely assembled and installed at sea, and this is only possible in calm weather.

Large-block foundations have become a more advanced design for such islands. According to their technical data, they are used at depths of 60-90 m. This is a significant step in the development of offshore oil and gas areas. In addition, foundations of this type made it possible to industrialize construction and installation work. Large foundation blocks are entirely manufactured in factories and delivered to the construction site at sea.

Here, a special crane vessel quickly assembles an artificial island and installs a drilling rig on it. Pile and large-block production sites are located at sea either in the form of separate foundations or connected to each other, and in many cases, to the shore by overpasses. From both of them, single and group (cluster) wells are drilled. Such offshore oil fields are most widespread in our country, as well as in the USA and Venezuela. Stationary foundations, mainly of a large-block design, can be used at depths of 100 meters and slightly more, but their construction requires very high costs.

Currently, mobile bases have begun to be used for offshore drilling. They are large platforms with a drilling rig, which are towed to the desired point, where they are installed on the bottom using retractable support legs.

To work at depths of more than 200 meters, unsupported platforms are designed and put into practice. One of them has been quite successfully exploited for 10 years at depths of about 200 meters by a French oil company, on whose order another similar platform is being built.

More mobile and therefore more effective remedy offshore deep-sea drilling - ships with drilling rigs on board. They drill through the keel, and modern electronic and hydroacoustic equipment ensures that the vessel is fixed in the right point and re-entry of drill pipes into the wellhead of a subsea well.

Even such a brief examination of the main means of developing oil and gas fields in the World Ocean shows that the extraction of oil and gas from the seabed is a complex and specific engineering problem, the solution of which requires large investments. The use of a particular mining technique depends on the natural conditions in the fishing area. The most significant influence on operating costs is: the depth of the site, the thickness and hardness of the rock in which drilling is carried out, hydrometeorological conditions (wind wave conditions, ice cover, etc.), the natural protection of the fishery and its distance from the coast. Now that serious attention is being paid to the inadmissibility of oil leakage into the sea, environmental protection measures are usually provided for in the fields, which is also associated with certain costs. The bottom topography between the shore and the offshore oil field determines the possibility of laying the pipeline underwater.

In addition, the extraction of oil and gas from the subsoil requires the use of expensive equipment. It is characterized by high overall production costs. For example, the cost of a drilling platform for work at depths of about 45 m is equal to 2 million dollars, at depths of 160-320 meters from 6 to 30 million dollars. The operating basis for deep-sea production in the Gulf of Mexico will cost 113 million dollars.

As already noted, with increasing depth in oil and gas fields, operating costs also increase markedly. At depths of about 15 meters, when using a mobile drilling rig, daily costs are 16 thousand, at depths of 40 meters - 21 thousand dollars. The use of a self-propelled platform at a depth of 30 meters increases costs to 1.5 million, and at a depth of 180 meters to 7 million. Doll.

Thus, the high cost of oil at depths of 300 meters or more makes it profitable only in large fields.

The costs of extracting “underwater” oil are not the same in different geographical conditions. The discovery of one field in the shallow Persian Gulf costs about $4 million, in the inland seas of Indonesia almost $5 million, and in the North Sea about $11 million.

A comparison of the total costs of oil production on land and at sea shows that they are partly more significant for the first, partly for the second developments. For example, exploration costs are higher on land, since only 12% of wells here produce commercial oil production, and 42% at sea. In continental fields, oil usually lies deeper than in offshore fields, so drilling on land penetrates a greater thickness of rock than at sea, and drilling is one of the most capital-intensive production processes. It is quite expensive to prepare a site for drilling on land.

The cost of a license to develop an offshore field is twice as high as a continental one. Large costs are associated with the use of special, expensive equipment. Construction of storage facilities and transportation of oil and gas to the shore require significant costs. At the same time, as a rule, the high industrial flow rate of offshore wells significantly reduces operating costs compared to operating costs for onshore production.

On average, extracting oil from the seabed is still somewhat more expensive than extracting it in the corresponding areas on land. In some water areas, searching for and extracting it has not yet become profitable. However, for global liquid fuel production as a whole, oil produced from the seabed has become competitive with oil produced on land. In addition, in modern conditions, demand for oil is outstripping supply. This entails an increase in prices and stimulates an increase in investment in the development of underwater oil fields. The total costs of exploration and production of oil from the bottom of the sea in capitalist countries reach approximately 1/3 of all costs in the oil and gas industry. In the early 70s, $25 billion was spent on the development of offshore oil and gas fields; by the early 80s, these expenses almost doubled. The largest investments in the development of underwater oil and gas fields in the early 70s came from the United States (about $19 billion), but in subsequent years they were outpaced by Canada, Australia and the North Sea states in terms of investment growth.

At prices as of January 2002, oil and gas obtained from offshore fields were sold for a total amount of about $100 billion, which was 4 times the cost of their production. This indicates that offshore oil and gas plays are now generating significant profits. They are significantly influenced by market conditions, which is generally manifested in two main aspects.

Firstly, the regular increase in prices for oil and gas in the last decade, together with the improvement of production technology, increases the profitability of offshore fields, since the costs of exploration and extraction of these types of fuel are more than covered by its sale at high market prices. At the same time, the use of new technology and modern methods storage and transportation of sea oil reduces its cost.

Secondly, the expansion of oil and gas production as a result of the development of offshore areas increases the fuel resources of developing countries - the main oil exporters and significantly weakens the dependence on oil imports of some developed countries, in particular Norway and the UK.

At the same time, many developed capitalist countries are characterized by a pronounced oil expansion, especially in relation to underwater deposits, since obtaining licenses for offshore fields is probably easier than for continental ones located on the territory of the state. Thus, the largest oil companies in the United States, countries that are less dependent on oil imports than other capitalist countries, are involved in the exploitation of offshore fields in the Middle East, off the coast of Mexico, Venezuela, in the North Sea and in other areas of the World Ocean, very remote from its shores.

Japan, which imports 99% of the oil consumed and 74% of natural gas, produces oil on an equity basis in the waters of some Middle Eastern states, but it is especially active in exploration on the shelf of countries South-East Asia, Australia, New Zealand with the prospect of developing their own oil and gas production here.

Such expansionist tendencies are exhibited not only by the national oil companies of Great Britain, France, Germany and other developed countries, but also by international ones.

Currently, the search for oil and gas is widespread in the World Ocean. Exploratory deep drilling is already being carried out over an area of about 1 million km2, and licenses have been issued for prospecting work on another 4 million km2 of the seabed. In the next 20 years it is expected to master deep drilling 3 million km 2 of underwater spaces. This will allow the development of new accessible offshore fields. However, with the ever-increasing demand for these types of fuel, marine industries, according to preliminary data, will only be able to meet the demands of developed countries for them. In the context of the gradual depletion of oil and gas reserves in many traditional land fields, the role of the World Ocean as a source of replenishment of these scarce fuels is noticeably increasing.

Oil and gas consumption is largely determined by market conditions, so it changes noticeably from year to year, sometimes over several years. The shortage of their own oil and gas and the desire to reduce dependence on their imports are stimulating many countries to expand the search for new oil and gas deposits. Development and generalization of the results of geological exploration have shown that the main source of production of several tens of billions of tons of oil and trillions of cubic meters of gas can be the bottom of the World Ocean.

According to modern concepts, a necessary geological condition for the creation of oil and gas in the bowels of the Earth is the existence of large-sized sedimentary strata in the areas of formation and accumulation of oil and gas. They form large oil and gas bearing sedimentary basins, which are integral autonomous systems where the processes of oil and gas formation and oil and gas accumulation occur. Offshore oil and gas fields are located within these basins, most of the area of which is located in the underwater depths of the oceans and seas. Planetary combinations of sedimentary basins represent the main belts of oil and gas formation and oil and gas accumulation on Earth. Geologists have established that in the gas oil reserve there is a complex of natural preconditions favorable for the development of large-scale processes of oil and gas formation and oil and gas accumulation.

One of the oldest and most developed areas of offshore oil and gas production is the Gulf of Mexico. About 700 industrial accumulations have been discovered off the American coast of the Gulf, which is about 50% of all deposits known in the World Ocean. 32% of the world's fleet of floating offshore installations and a third of all wells drilled in offshore fields are concentrated here.

The development of the offshore oil and gas industry in the Gulf of Mexico was accompanied by the creation of a complex of related industries - special engineering, shipyards for the construction of floating and stationary drilling platforms, a shipyard for the creation of an auxiliary fleet, a support base and helipads, tanker berths and terminal facilities, oil refineries and gas treatment plants, and onshore reception facilities. capacities and distributors at the mouths of offshore pipelines. Particular mention should be made of the creation of an extensive network of underwater oil and gas pipelines. Houston, New Orleans, Houma and other cities became centers of the offshore oil and gas industry on the coast.

The development of offshore oil and gas production in the United States contributed to the elimination of their dependence on any regional source, in particular on Middle Eastern oil. To this end, offshore oil production is being developed in the California coastline, and the Bering, Chukchi, and Beaufort seas are being developed.

The Gulf of Guinea is rich in oil, whose reserves are estimated at 1.4 billion tons, and annual production is 50 million tons.

The discovery of the large North Sea oil and gas province with an area of 660 thousand square kilometers was sensational. The availability of oil and gas resources in the North Sea countries turned out to be extremely unequal. Nothing has been identified in the Belgian sector, and very few deposits have been discovered in the German sector. Norway's gas reserves, which controls 27% of the North Sea shelf area, are higher than those of the UK, which controls 46% of the shelf area, but the main oil deposits are concentrated in the UK sector. Exploration work in the North Sea continues. Covering ever deeper waters, new deposits are being discovered.

The development of the oil and gas resources of the North Sea is proceeding at an accelerated pace based on large capital investments. High oil prices have contributed to the rapid development of North Sea resources and even a decline in production in the richer, profitable areas of the Persian Gulf. The North Sea has taken first place in hydrocarbon production in Atlantic Ocean. 40 oil and gas fields are exploited here. Including 22 off the coast of Great Britain, 9 - Norway, 8 - the Netherlands, 1 - Denmark.

The development of North Sea oil and gas led to shifts in the economies and foreign policies of some countries. In the UK, related industries quickly began to develop; there are more than 3 thousand companies associated with marine and oil and gas work. In Norway, there has been a flow of capital from traditional industries - fishing and shipping - to the oil and gas industry. Norway has become a major exporter of natural gas, providing the country with a third of export earnings and 20% of all government revenues.

3. Solid minerals of the world's oceans

The extraction of solid minerals from the World Ocean largely depends on the development and establishment of marine geology and marine mining.

Until now, it was concentrated in the shelf zone at a depth of up to 200 m, i.e., it gravitated towards land and practically developed in the same ways as in continental developments.

Coal, iron ores, tin, and sulfur are extracted from the primary deposits of the seabed. Mines and mines under the seabed have an extensive network of mining workings. In Japan, more than 30% of coal is mined from such mines, in England - 10%. One of the largest high-productivity iron ore enterprises in the world is the Canadian Wabana mine, opened by inclined workings from Bell Island.

The shelf zone - relatively accessible in technical terms - occupies one fifth of the area of the continents. Structurally, it is a continuation of the continental platforms below sea level. The probability of discovering deposits of solid minerals in sedimentary and bedrock of the shelf floor is the same as in continental conditions. This is an important circumstance: in our country, the shelves occupy an area of about 6 million km8 (21.8% of the total shelf area in the World Ocean).

Recently, foreign countries have attached particular importance to the development of deep-sea ore deposits discovered in the central regions of the oceans and in some faults of the earth's crust at the bottom of the seas and oceans. Deposits suitable for development contain on average up to 2% nickel, cobalt and copper, about 20% manganese, as well as a number of other valuable elements. The average density of nodules in promising areas reaches 10 kg per 1 m3 of bottom area. According to rough estimates, profitable production can be ensured by an enterprise that annually produces 3 million tons of dry nodules.

Solid minerals extracted from the sea so far play a much smaller role in the marine economy than oil and gas. However, here too there is a tendency towards rapid development of production, stimulated by the depletion of similar reserves on land and their uneven distribution. In addition, the rapid development of technology has led to the creation of improved technical means capable of conducting developments in coastal zones.

Deposits of solid minerals in the sea and ocean can be divided into bedrock, which are found at the site of their original occurrence, and alluvial deposits, the concentrations of which are formed as a result of the removal of clastic material by rivers near the coastline on land and in shallow waters.

Indigenous, in turn, can be divided into buried, which are extracted from the depths of the bottom, and surface, located on the bottom in the form of nodules, silts, etc.

After oil and gas, alluvial minerals are currently of greatest importance. Solid minerals deposits of metal-bearing minerals, diamonds, building materials and amber. indigenous placers. For certain types of raw materials, marine placers are of predominant importance. They contain dozens of different buried surface minerals, including heavy minerals and metals, which are in demand on the global foreign market. The most significant of them include ilmenite, rutile, zircon, monazite, magnetite, cassiterite, tantalum-niobites, gold, platinum, diamonds and some others. The largest coastal-marine placers are known mainly in the tropical and subtropical zones of the World Ocean. At the same time, placers of cassiterite, gold, platinum and diamonds are much rare; they are ancient alluvial deposits, submerged under sea level, and are located close to the areas of their formation.

Minerals of coastal-marine placer deposits such as ilmenite, rutile, zircon and monazite are the most widespread, “classical” minerals of marine placers. These minerals have a high specific gravity, are resistant to weathering and form industrial concentrations in many areas of the coasts of the World Ocean.

The leading place in the extraction of placer metalliferous minerals is occupied by Australia, its eastern coast, where placers stretch for one and a half thousand kilometers. The sands of this strip alone contain about 1 million tons of zircon and 30.0 thousand tons of monazite.

The main supplier of monazite to the world market is Brazil. The USA is also a leading producer of ilmenite, rutile and zircon concentrates (placers of these metals are almost ubiquitous on the shelf North America- from California to Alaska in the west and from Florida to Rhode Island in the east). Rich ilmenite-zircon placers were found off the coast of New Zealand, in coastal placers of India (Kerala), Sri Lanka (Pulmoddai region). Less significant coastal-marine deposits of monazite, ilmenite and zircon were discovered on the Pacific coast of Asia, on the island of Taiwan, on the Liaodong Peninsula, in the Atlantic Ocean off the coast of Argentina, Uruguay, Denmark, Spain, Portugal, the Falkend Islands, South Africa and in some other areas.

Much attention in the world is paid to the extraction of cassiterite concentrate - a source of tin. The world's richest coastal-marine and underwater alluvial placer deposits of tin ore - cassiterite - are concentrated in the countries of Southeast Asia: Burma, Thailand, Malaysia and Indonesia. Of significant interest are cassiterite placers off the coast of Australia, off the Cornwall peninsula (Great Britain), in Brittany (France), and on the northeastern coast of the island of Tasmania. Offshore deposits are becoming increasingly important due to depletion of onshore reserves and because offshore deposits have proven to be richer in metal content than onshore ones.

More or less significant and rich coastal-marine placers of magnetite (iron-containing) and titanomagnetite sands are found on all continents. However, not all of them have industrial reserves.

The largest accumulations of ferruginous sands in terms of reserves are located in Canada. Japan has very significant reserves of these minerals. They are concentrated in the Gulf of Thailand, near the islands of Honshu, Kyushu and Hokkaido. Ferrous sands are also mined in New Zealand. The development of coastal-marine magnetite placers is carried out in Indonesia and the Philippines. In Ukraine, alluvial titanomagnetite deposits are exploited on the beaches of the Black Sea; in the Pacific Ocean - near the island of Insurut. Promising deposits of tin-bearing sand have been discovered in Vankova Bay in the Laptev Sea. Coastal magnetite and titanomagnetite placers are found on the coasts of Portugal, Norway (Lofopian Islands), Denmark, Germany, Bulgaria, Yugoslavia and other countries.

Sporadic minerals of coastal-marine placers include primarily gold, platinum and diamonds. All of them usually do not form independent deposits and are found mainly in the form of impurities. In most cases, marine gold placers are confined to the mouth areas of “gold-bearing” rivers.

Placer gold in coastal-marine sediments was discovered on the western shores of the USA and Canada, Panama, Turkey, Egypt, and the countries of South-West Africa (the city of Nome). Significant concentrations of gold are found in the underwater sands of the Stefans Strait, south of the Grand Peninsula. The commercial gold content has been established in samples recovered from the bottom of the northern Bering Sea. Exploration of coastal and underwater gold-bearing sands is actively carried out in different areas of the ocean.

The largest underwater deposits of platinum are located in Goodnews Bay (Alaska). They are confined to the ancient beds of the Kuskokwim and Salmon rivers, flooded by the sea. This deposit provides 90% of the US needs for this metal.

The main deposits of coastal-marine diamondiferous sands are concentrated on the southwestern coast of Africa, where they are confined to terrace, beach and shelf deposits to depths of 120 m. Significant marine terrace diamond placers are located in Namibia, north of the Orange River, in Angola (in the area Luanda), on the coast of Sierra Leone. African coastal-sea placers are promising.

Amber, an object of decoration and a valuable raw material for the chemical and pharmaceutical industries, is found on the shores of the Baltic, North and Barents seas. Amber is mined on an industrial scale in Russia.

Among the non-metallic raw materials in the shelf zone, glauconite, phosphorite, pyrite, dolomite, barite, and building materials - gravel, sand, clay, shell rock - are of interest. Non-metallic raw material resources, based on the level of modern and foreseeable needs, will last for thousands of years.

Many coastal countries are engaged in intensive extraction of building materials at sea: the USA, Great Britain (English Channel), Iceland, Ukraine. In these countries, shell rock is mined and used as the main component in the production of construction lime, cement, and feed meal.

The rational use of marine building materials involves the creation of industrial complexes for the enrichment of sands by cleaning them from Rakusha and other impurities and recycling Rakusha in various sectors of the economy. Shell rock is mined from the bottom of the Black, Azov, Barents and White Seas.

The data presented indicate that a coastal mining industry has now formed. Its development in recent years has been associated, firstly, with the development of new technologies, secondly, the resulting product is characterized by high purity, since foreign impurities are removed during the formation of the placer, and thirdly, the development of coastal-marine placers does not entail withdrawal of productive lands from land use.

It is characteristic that countries that produce concentrates from mineral raw materials extracted from coastal sea placers (except for the USA and Japan) do not use their products, but export them to other countries. The bulk of these concentrates are supplied to the world market by Australia, India and Sri Lanka, and to a lesser extent by New Zealand, southern African countries and Brazil. These raw materials are imported on a large scale by Great Britain, France, the Netherlands, Germany, the USA, and Japan.

Currently, the development of coastal-marine placers is expanding throughout the world, and more and more countries are beginning to develop these ocean resources.

In recent years, favorable prospects have emerged for the extraction of primary deposits of the marine subsoil using the mining method. More than a hundred underwater mines and mines are known, founded from the shores of continents, natural and artificial islands for the extraction of coal, iron ore, copper-nickel ores, tin, mercury, limestone and other buried minerals.

In the coastal zone of the shelf there are underwater deposits of iron ore. It is mined using inclined mines that extend from the shore into the depths of the shelf. The most significant development of offshore iron ore deposits is carried out in Canada, on the east coast of Newfoundland (Wabana deposit). In addition, Canada mines iron ore in the Hudson Bay, Japan - on the island of Kyushu, Finland - at the entrance to the Gulf of Finland. Iron ores are also obtained from underwater mines in France, Finland, and Sweden.

Copper and nickel are extracted in small quantities from underwater mines (Canada - in the Hudson Bay). Tin mining is carried out on the Cornwall peninsula (England). In Turkey, on the coast of the Aegean Sea, mercury ores are mined. Sweden mines iron, copper, zinc, lead, gold and silver in the Gulf of Bothnia.

Large salt sedimentary basins in the form of salt domes or strata deposits are often found on the shelf, slope, foot of continents and in deep-sea depressions (Gulf of Mexico and Persian Gulf, Red Sea, northern part of the Caspian Sea, shelves and slopes of Africa, the Middle East, Europe). The minerals of these basins are represented by sodium, potassium and magnesite salts, and gypsum. Calculating these reserves is difficult: the volume of potassium salts alone is estimated to range from hundreds of millions of tons to 2 billion tons. The main need for these minerals is met through deposits on land and extraction from seawater. There are two salt domes in operation in the Gulf of Mexico off the coast of Louisiana.

More than 2 million tons of sulfur are extracted from underwater deposits. The largest accumulation of sulfur, Grand Isle, located 10 miles off the coast of Louisiana, is exploited. A special island was built here for the extraction of sulfur (extraction is carried out using the flash method). Salt dome structures with possible industrial sulfur content have been found in the Persian Gulf, Red and Caspian Seas.

Others worth mentioning mineral resources, occurring mainly in the deep-sea regions of the World Ocean. Hot brines and muds rich in metals (iron, manganese, zinc, lead, copper, silver, gold) have been discovered in the deep-sea part of the Red Sea. The concentrations of these metals in hot brines exceed their content in sea water by 1 - 50,000 times.

More than 100 million square kilometers ocean floor covered with deep-sea red clays with a layer up to 200 m thick. These clays (hydroxides of aluminosilicates and iron) are of interest for the aluminum industry (aluminum oxide content - 15-20%, iron oxide - 13%), they also contain manganese, copper, nickel, vanadium , cobalt, lead and rare earths. The annual increase in clays is about 500 million tons. Glauconitic sands (potassium and iron aluminosilicates) are widespread, mainly in the deep-sea regions of the World Ocean. These sands are considered a potential raw material for the production of potash fertilizers.

The world is particularly interested in nodules. Huge areas of the seabed are covered with ferromanganese, phosphorite and barite nodules. They are of purely marine origin, formed as a result of the deposition of water-soluble substances around a grain of sand or small pebble, shark tooth, fish or mammal bone.

Phosphorite nodules contain an important and useful mineral - phosphorite, which is widely used as a fertilizer in agriculture. In addition to phosphorite nodules, phosphorites and phosphorus-containing rocks are found in phosphate sands, in stratal deposits of the ocean floor, both in shallow and deep-sea areas.

The world's potential reserves of phosphate rock in the sea are estimated at hundreds of billions of tons. The demand for phosphorites is constantly increasing and is mainly satisfied by onshore deposits, but many countries do not have onshore deposits and are showing great interest in offshore ones (Japan, Australia, Peru, Chile, etc.). Industrial reserves of phosphorites have been found near the Californian and Mexican coasts, along the coastal zones of South Africa, Argentina, the east coast of the United States, in the shelf parts of the periphery of the Pacific Ocean (along the Japanese main arc), off the coast of New Zealand, and in the Baltic Sea. Phosphorites are mined in the California region from depths of 80-330 m, where the concentration averages 75 kg/m3.

What can be obtained from the World Ocean

Extraction of heavy metals from the seabed

Water sorts minerals

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