3.Geology of the Leningrad region
Geolaboutgia(from geo ... and ... ology), a complex of sciences about the earth's crust and deeper spheres of the Earth; in the narrow sense of the word - the science of the composition, structure, movements and history of the development of the earth's crust and the placement of minerals in it. Most of the applied and theoretical problems solved by geology are connected with the upper part of the earth's crust, accessible to direct observation.
Engineering geology- the science of the formation and change of engineering and geological conditions, territories, the geological conditions for the construction and operation of structures, the rational use of the geological environment, to create safe and comfortable conditions for human life.
Engineering survey for construction - work carried out for a comprehensive study of the natural conditions of the area, site, site, route of the projected construction, local building materials and water supply sources and obtaining the necessary and sufficient materials for the development of economically viable and technically sound solutions in the design and construction of facilities, taking into account rational use and protection of the natural environment, as well as obtaining data for making a forecast of changes in the natural environment under the influence of the construction and operation of enterprises, buildings and structures.
Engineering surveys are one of the most important types of construction activities, they begin any process of construction and operation of facilities. An integrated approach that combines various types of engineering surveys allows for a versatile and timely inspection of construction sites, buildings and structures.
The main types of surveys in construction:
Engineering and geodetic;
Engineering-geological;
Engineering and hydrometeorological;
Engineering and environmental (mobilization work; field work; laboratory; cameral work);
Surveys of soil building materials (experimental field work; survey of earthworks during their reconstruction).
Geology of the Leningrad region.
The Leningrad region is rich in natural monuments. These are not only individual geological, water, botanical objects, but also integral parts of nature - territories, water areas. Territorial monuments include tracts protected by the state - areas with untouched especially picturesque nature, scientifically valuable areas of valleys, coasts of seas and lakes, river sources, relict lakes ...
Monuments of geological history on the territory of the Leningrad region are found in the form of picturesque rocks and geological outcrops that reveal the historical past of the Earth, as well as in the form of caves, waterfalls, boulders and some other formations.
These natural objects are called monuments because they testify to the history of nature and the processes taking place in it, help us to reveal many of its secrets.
Thus, the remains of petrified fauna in geological outcrops allow us to determine the age of the rocks that make them up and often help organize the search for various minerals. Accumulations of boulders in the fields indicate the activity of the glacier in bygone years ...
The geological past of our region is complex and diverse.
In the northern part of the Karelian Isthmus, the oldest igneous rocks, granites, come to the surface. Their study allows us to penetrate not only into the depths of the Earth, but also into the depths of centuries. They say that in the distant Precambrian time, when there was no organic life on Earth yet, flows of fiery-liquid lava-magma rose from its bowels, accompanied by diverse processes: volcanic eruptions, earthquakes, vertical and horizontal displacements of individual sections of the earth bark and other phenomena. At the surface of the Earth, magma cooled, solidified and turned into granites.
Granites on the Korelsky Isthmus
The oldest Archean and Proterozoic rocks - granites, diorites and altered - metamorphic - gneisses of the Karelian Isthmus form part of the so-called Baltic crystalline shield.
South of the Vuoksa River, they go to a greater depth, under younger sedimentary formations of the Upper Proterozoic and Paleozoic ages.
From the beginning of the Paleozoic, almost the entire territory of the Leningrad Region was covered by the sea, at the bottom of which various sedimentary rocks were deposited.
At the base of the Paleozoic deposits are sandstones and blue Cambrian clays (age about 6 centuries Ma). They are well known to the Leningrad metro builders, since most of the tunnels were passed through blue clay. These clays are poor in organic remains, as are the sandstones lying above.
The deposits of the next, Ordovician period are more diverse. These are sandstones, limestones, dolomites, argillaceous and combustible shales. They come directly to the surface south of Leningrad within the so-called Ordovician plateau.
The plateau is a flat elevated plain with absolute surface elevations of 2 to 8 meters. To the south of Leningrad, the plateau abruptly ends with a high, up to 4 meters, ledge, which is called the Baltic-Ladoga Glint (from the Danish word "glint"
- cliff, cliff, ledge). 
Ledge of the Baltic-Ladoga Glint
Glipt stretches in a latitudinal direction, 2-25 kilometers south of the Neva River and the Gulf of Finland, across the entire Leningrad Region, from the Syasi River to the west to the city of Paldiski in the Estonian SSR.
The Glint is crossed by the rivers Koporka, Izhora, Sablinka, Tosna, Lava and others. It is here that there are mainly geological outcrops - natural monuments.
The western, elevated part of the Ordovician plateau is called the Izhora Upland (up to 176 meters of absolute height). Its distinctive feature is the almost complete absence of rivers and lakes. The proximity to the earth's surface of rocks, such as limestones, easily soluble by surface and underground waters, gave rise here to the development of the so-called karst processes. They consist in the destruction of limestone and the formation of numerous failed funnels, underground channels and cracks in them, through which water flows down. 
r.Sablinka
The largest deposits of minerals in our region are associated with the Ordovician deposits. One of them is a phosphorite deposit near the city of Kingisepp. It is being developed by a production association. In addition to Kingisepp, several other phosphorite deposits have been discovered in the Leningrad Region. In all cases, a useful component is phosphate, represented by fragments and whole valves of shells of marine mollusks - brachiopods that lived at the bottom of the Ordovician Sea. Shells contain 35-37 percent phosphorus pentoxide. 
Plant "Phosphorite"
Oil shale deposits are also associated with Ordovician deposits (Slantsevsky district). The first ton of shale in our region was mined in 1934, when mine N1 began to operate (later it was named after S. M. Kirov). Now there are three mines in Slantsy, in which up to 5 million tons of shale are mined annually.
In addition, Ordovician limestones are of great importance for the national economy. They are developed as raw materials for metallurgy, cement and glass industries. The largest deposits are Pikalevskoye and Kikerinskoye. The total thickness of the Ordovician deposits is 2vv-3vv meters.
There are no Mesozoic and Tertiary sediments on the territory of our region, since by this time the sea had left the Leningrad region.
The entire listed ancient Paleozoic sedimentary sequence lies almost horizontally on the crystalline basement. Overlying are Quaternary deposits, which began to form about 5-1.5 million years ago, and continue to accumulate in our time. They consist of glacial, water-glacial, lake, river, sea and swamp formations. Their thickness within the Neva River valley reaches 5 meters and more, in some parts of the eastern region it exceeds 1 century meters.
Most scientists believe that the modern relief was formed mainly as a result of the activity of the glacier in the Quaternary period. At that time, the territory of our region was repeatedly covered with continental ice. During the last interglacial epoch (about 85-75 thousand years ago) the northern part of the region was flooded by sea waters. As a result of the transfer and deposition of sediments by glaciers and melted glacial waters, peculiar forms of modern relief arose in the form of a disorderly accumulation of hills, often alternating with depressions, often occupied by lakes and swamps, the so-called hilly-morainic relief, if the hills are composed of loams with rubble and boulders, and kame relief, if the hills are composed of sands.
At the end of the last glaciation, about 12 thousand years ago, during the melting of the glacier, water also accumulated in the pre-glint lowland. At this time, a large body of water was formed, connecting the waters of the Gulf of Finland with Lake Ladoga, the central part of the Karelian Isthmus was then an island. Finally, the contours of the modern relief were formed relatively recently, only 4.5-5 thousand years ago.
Table of minerals of the Leningrad region:
|
Field |
Reserves (thousand tons) |
|
Kingisepp deposit of phosphate ores | |
|
Leningrad oil shale deposit (city of Slantsy) | |
|
Radynsky bauxite mine (mining stopped) | |
|
Iron-manganese nodules in the Gulf of Finland |
ore - 2411 manganese - 188 576 |
|
Pikalevskoe deposit of flux limestones | |
|
Slantsevskoye limestone deposit |
more than 9,000, with the Borovnya deposit - more than 45,000 |
|
Diamond tubes |
no commercial production |
|
Radon springs near the village of Lopukhinka and Voronino | |
|
Mineral thermal waterspod Lugoj | |
|
Leningrad thermal anomaly (deposit of thermal underground waters) |
Scheme of the location of natural monuments on the territory of the Leningrad region.
1. Sablinsky caves and waterfall. 2. Geological outcrops on the Popovka River. 3. Geological outcrops on the Oredezh River. 4. Geological outcrops near Staraya Ladoga. 5. Duderhof heights. 6. Disappearing river Ragusha. 7. Vyborg granites. 8. Lakeside granites. 9. Zhikharevskaya cave. 1c. Radon lake in Lonukhinka. 11. Balun "Old Man". 12. Springs of the village of Kipen. 13. Sestroretsky dunes. 14. Geological outcrops near the village of Yam-Tesovo. 15. Geological outcrops near Lake Antonovsky. 16. Lava river canyon. 17. Granites of Yastrebinoye Lake. 18. Granites on Gustom Island. 19. Gabbro-norites Shcheleyki. 2c. Lake Red. 21. Sources of the Donets tract. 22. New Ladoga Dunes. 23. End-moraine ridge Michurinskaya. 24. Geological outcrops on the Saba River. 25. Olginsky boulder. 26. Toksovskie kamy. 27. Kamy Kirsino-Shapki. 28. Dunes of Fox Mountain.
Soils.
Soddy-podzolic soils
The main type of soils in the region are podzolic, poor in humus and characterized by significant acidity. At the same time, on loams, in low places with increased accumulation of moisture, mainly in spruce forests, strongly podzolic soils with a thick upper layer are formed. In higher places, less favorable for the accumulation of moisture, medium podzolic soils are formed. On sandy loams and sands that do not retain moisture well, slightly podzolic soils are found in pine forests. Where herbaceous vegetation predominates - in forest clearings, in rare mixed or deciduous forests - formed
On the territory of the Izhora Upland, on rocks containing lime, which neutralizes acidity and protects the topsoil from leaching, soddy-calcareous soils have formed. These are the best among the soils of the region: they are richer than others in humus and minerals, and have a well-defined lumpy structure. They are also called "northern chernozems".
In lowlands and on flat areas, with a weak runoff (poor drainage) of atmospheric waters, causing them to stagnate on the surface, and sometimes with a high level of standing groundwater, peaty and swampy soils are formed. They are distributed in the central part of the region, in the east of the Karelian Isthmus, on the coast of the Gulf of Finland, in the Ladoga region.
In some places, on meadow terraces (along the rivers Volkhov, Luga and others), flooded with water during floods, alluvial soils rich in humus are formed from river sediments. Their area is small.
The main soil-forming rocks are clays, loams, sands and peat. The agricultural use of the region's soils requires their artificial improvement.
Leningrad region
The Leningrad region is one of the northwestern regions of Russia. It is located in the north-west of the East European Plain and to the Gulf of Finland of the Baltic Sea for 330 km. In the west, the region borders on the Narva River with Estonia, in the northwest - with Finland, in the north and northeast - with Karelia, in the east - with the Vologda region, in the south and southeast - with the Novgorod and Pskov regions.
The Leningrad region is located in the temperate latitudes of the northern hemisphere, in the forest zone, at the junction of the taiga and mixed forest subzones, between 58.26" and 61.20" north latitude and 27.45" and 35.40" east longitude. The area of the Leningrad region is 85.9 thousand square kilometers (0.5% of the area of Russia). Center - St. Petersburg - the second largest industrial center of Russia. It is not administratively part of it, but forms an independent administrative unit of Russia. There are 16 administrative districts and 26 cities in the Leningrad Region, including 15 cities of regional subordination, that is, not included in the districts.
Relief.
The foundation of the Russian platform, within which the Leningrad region is located, is composed of diabases, gneisses and granites. These ancient crystalline rocks come to the surface only in some places in the north of the Karelian Isthmus.
To the south, on the ancient crystalline rocks, there are everywhere powerful strata of various sedimentary rocks deposited in the seas that covered this territory for many millions of years. Although in the south of the region the foundation is located at a considerable depth (800-1000 m), nevertheless, the most significant upland, Vepsovskaya, basically has ledges. 200-300 million years ago, the territory of the Leningrad region became dry land, sedimentary rocks were destroyed under the influence of weathering and the erosion of rivers. Loose rocks - sands, clays - collapsed faster than dense rocks - limestones, sandstones. Thus, large irregularities were formed, clearly expressed in the modern relief of the region: lowlands in place of loose rocks (Vuoksinskaya, Prinevskaya lowlands, etc.) and plateau-like uplands composed of dense rocks (Izhora Upland).
The relief has been greatly altered during glacial times by the activity of continental ice and melted glacial waters, and more recently by the activity of the sea, flowing waters, wind, and also people. The territory of the Leningrad region has experienced several glacial epochs, which alternated with interglacial epochs. The last glaciation ended 12,000 years ago.
Glaciers advancing from the north carried large boulders of crystalline rocks from the Scandinavian rocks; they plowed the surface and captured loose rocks. When the glacier retreated, the moraine melted out of it and was deposited on the pre-glacial layers.
After the ice melted, glacial reservoirs arose in its place. Lakes formed in hollows and hollows, and in higher areas, melted glacial waters eroded glacial deposits and leveled the surface. After the decline of the waters, the dried-up reservoirs turned into flat plains, in which the rivers cut through the valleys.
The moraine-glacial relief of the region is also characterized by hills and ridges of various shapes and heights. These are ozy - long shafts of coarse sand and gravel 10-15 m high, kams - rounded high hills up to 50 m high, formed from fine sand, sands - wavy sandy spaces that arose at the mouth of former glacial rivers. There are especially many moraine hills on the hills. They are rarely combined with lake and marsh depressions. On the territory of the Leningrad region there are hills.
Vepsovskaya Upland - the northeastern continuation of the Valdai Upland - is located in the east of the region and serves as a watershed for the basins of Lake Ladoga and the Volga River. The hills that form a hill in the north, near the sources of the Oyat River, reach the highest absolute height in the region - 291 m (Gapselga ridge), to the south, the absolute heights decrease to 200-150 m. Hills and ridges alternate with heavily marshy flat plains, lake and marsh depressions. The relative height of the hills above the depressions adjacent to them usually does not exceed 50 m. The relief of the hill is unfavorable for agriculture.
The highest height of the hill located in the central part of the Karelian Isthmus is 205 m. It is called the Lembolov Heights. It is characterized by numerous gently sloping moraine hills, a dense river network and shallow, partly overgrown lakes. Around the hill there is a hilly-kam relief. Near St. Petersburg, such a relief is most pronounced in the Toksovo and Kavgolovo regions.
Numerous kames with steep slopes, covered with pine; closed basins separating them, overgrown with spruce and deciduous forests; deep lakes with a sandy bottom; open, mostly plowed, plateaus - all this diversifies the relief, makes it very picturesque.
The Kavgolovo area is a favorite place for skiers. Above the steep slope of one of the kams in Kavgolovo, a huge springboard has been built, where national and international ski competitions are held.
The Izhora Upland is located south of the Gulf of Finland. Its surface is flat and inclined towards the southeast. The highest part of the hill is the northern one, where (near the village of Mozhaysky) Voronya Gora (168 m) is located. In the north, the hill abruptly breaks off, forming a ledge (it is called a glint). The Izhora Upland is composed of limestones, dolomites and marls, which in some places come to the surface. The limestones are fissured, and atmospheric precipitation seeps almost completely into the depths, forming groundwater that feeds numerous springs on the outskirts of the plateau. Water seeping deep into the limestone dissolves - karst landforms are formed; they are widespread in the Izhora Upland.
The eastern part of this upland is the Putilov plateau with absolute heights of 50-90 m. The plateau ends in a steep ledge, a continuation of the clint, towards Lake Ladoga.
The limestones, marls and dolomites composing it lie lower than on the Izhora Upland, and the layer of glacial deposits covering them is thicker. In conditions of flat relief, this contributes to waterlogging. The plateau is cut through by deep valleys of the Volkhov, Tosna, Syasi rivers, which, crossing the ledge, form rapids and waterfalls.
A significant part of the region's area is occupied by lowlands and lowland plains. Coastal lowlands are located along the shores of the Gulf of Finland and Lake Ladoga.
The lowland, stretching along the southern coast of the Gulf of Finland, is bounded from the south by a clint. It consists of several flat terraces rising up in ledges. These terraces and ledges are traces of the gradual lowering of the level of the glacial sea that existed during the last glaciation on the site of the Baltic Sea. The sea was dammed from the north by the edge of the glacier, and the level of this sea exceeded the level of the present sea.
The slopes of the glint, facing the coastal lowland, are cut by deep ravines, in which groundwater, flowing from the Izhora Upland, emerges in the form of springs. The rivers flowing along the lowlands to the bay begin from them. Terraces are also pronounced on the coastal lowland along the northern shore of the bay. The lowland is separated by a steep ledge from the lacustrine plain in the west of the Karelian Isthmus. The coastal lowlands are characterized by windblown sand dunes; their relative height is 10-30 m, and the width in some places is more than 10 km (for example, near Sestroretsk). The gentle slopes of the dunes face the sea towards the blowing winds. The lee slopes are steep and crumbling. Where the dunes are bare, they move slowly in the direction of the wind. Therefore, they are fixed with vegetation, mostly pines.
The coastal lowland of Lake Ladoga is part of a vast lake basin. It consists of glacial and post-glacial terraces of the lake and deltas of the Svir, Pasha and Syasi rivers.
The lower terrace of the lowland is a flat plain with ridges of dunes overgrown with pine and ancient sandy coastal ridges - traces of post-glacial reservoirs. On the upper terraces, low hills (moraine and ancient dunes) alternate with marshy depressions and deep valleys of rivers flowing to the lake.
The low-lying relief also prevails in the southern and eastern regions of the region, lying to the south of the Izhora Upland and to the west of the Veps Upland. Most of this vast territory is occupied by the western and northeastern outskirts of the Priilmenskaya lowland. Among the predominantly flat, heavily swamped areas, there are moraine and sandy hills and hollows with lakes. Some rivers have carved deep and wide valleys (for example, Luga). Most of the river valleys arose in the post-glacial period; such valleys are not deep (for example, the valley of the Volkhov River).
The group of lake-river lowlands is located on the Karelian Isthmus. The Vyborg lake plain and the Vuoksa lowland occupy its northern part, and the Prinevskaya lowland occupy its southern part.
Minerals.
The Leningrad region is relatively rich in various minerals. Their composition, occurrence conditions and placement of deposits are closely related to the geological structure of the region.
Bauxites (near the city of Boksitogorsk; ores are shallow and can be mined by open pit), oil shale (near the city of Slantsy; depth of occurrence is 80-300 m, mining by a mine method) and phosphorites (near the city of Kingisepp) are of the greatest industrial importance.
The Leningrad region has huge reserves of granite, limestone, brick and refractory clay, building and molding sand and other building materials, mineral paints. There are large sources of mineral waters (Polyustrovskiye carbonic in St. Petersburg, sulfur water in Sablino, sodium chloride in Sestroretsk).
Granite is mined in the north of the Karelian Isthmus, where the ancient crystalline foundation comes to the surface. Limestones are widespread in the region. Depending on the times of formation, different properties. The ancient limestones that make up the Izhora Upland are very dense and break into large slabs. The most significant limestone deposits are concentrated in the area of the clint and in the area of the city of Pikalevo, in the east of the region.
More than 2,300 peat deposits have been discovered in the region. Peat reserves in the region exceed 17 billion cubic meters. The largest peat deposits are located in the lowland areas of the region, especially in the south and east.
Climate.
The climatic conditions of the Leningrad region, as well as the whole other territory, are primarily affected by its geographical position, which determines the angle of inclination of the sun's rays to the surface and the length of the day, and, consequently, the income and consumption of solar heat.
In general, for the year in our latitudes, the difference between the inflow of solar heat and its consumption (for heating the earth's surface and air, for evaporating water and melting snow) is positive. However, the flow of solar heat throughout the year is uneven, due to large changes in the height of the sun above the horizon (at noon at 60 degrees N - from 6.30 "in December to 53 degrees in June) and day length (from 5 hours 30 minutes in December to 18:30 in June).
From April to October, the arrival of solar heat in the Leningrad Region exceeds its consumption, and from November to March, the heat consumption is greater than its arrival.
Changes in the ratio of solar heat input and output throughout the year are associated with seasonal temperature changes that affect all other elements of the climate.
The movement of air masses of various origins also has a huge impact on the climate of the Leningrad Region.
The number of days in a year with the predominance of maritime and continental air masses is approximately the same, which characterizes the region's climate as transitional from continental to maritime.
From the west, from the side of the Atlantic Ocean, humid sea air of temperate latitudes enters the territory of the region. In winter, it is warm and makes up for the lack of solar heat, causing thaw, rain and sleet. In summer, the arrival of this air causes rain and cool weather. Continental air from temperate latitudes enters the territory of the region most often from the east, but sometimes from the south and southeast. He brings dry and clear
weather: warm in summer, very cold in winter.
From the north and northeast, mainly from the Kara Sea, dry and always cold Arctic air comes in, forming above the ice. Intrusions of this air are accompanied by the onset of clear weather and a sharp drop in temperature.
Arctic maritime air enters from the northwest. Compared to the air coming from the northeast, it is less cold, but more humid. In summer, masses of tropical air occasionally invade the territory of the region, humid sea air from the southwest and very dry, dusty air from the southeast; they bring hot weather.
Air masses often change, which is associated with frequent cyclonic activity (in St. Petersburg, about 40% of all days of the year are with cyclones). The consequence of this is the unstable weather characteristic of the Leningrad Region.
The average annual air temperature drops in the Leningrad Region from west to northeast from +4.5C to +2.0C. The coldest month in the region is January or February. The average January temperature in the east of the region is -10C, in the west -6C. In St. Petersburg, the average temperature in January is -7.5C, in February -7.9C.
The warmest month in the region is July. The average daily temperature in July in St. Petersburg is +17.7C; deviations from it within the region are small (+16C near the coast of Lake Ladoga, about +18C in the southeast).
Average monthly air temperature (in degrees Celsius):
The duration of the period with an average daily air temperature above 5C in the east of the region is approximately 160, and in the southwest - 170 days. The sum of average daily temperatures on days with temperatures above 10C is 1600-1800.
The area is characterized by high cloud cover. During the year in St. Petersburg, on average, there are only 30 cloudless days. In winter there is a lot of cloudiness. This slows down the drop in air temperature, as clouds prevent the outflow of heat from the lower atmosphere. The least cloudiness is in spring and early summer, the most in autumn.
The entire territory of the Leningrad region is located in the zone of excessive moisture. Relative humidity is always high (from 60% in summer to 85% in winter). The average annual amount of precipitation, which is 550-650 mm, is 200-250 mm more than the amount of evaporating moisture. This contributes to the waterlogging of the soil. Most of the precipitation falls between April and October. The greatest amount of precipitation (750-850 mm per year) falls on the elevated parts of the region.
Average monthly rainfall (in mm):
Much of the precipitation falls in the form of snow. A stable snow cover lies for about 127 days in the southwest of the region and up to 150-160 days in the northeast. By the end of winter, the height of the snow cover in the northeast reaches 50-60 cm, and in the west, where thaws often occur, it usually does not exceed 30 cm.
The climate of St. Petersburg has some peculiarities. In summer, during the day, stone buildings, pavements and sidewalks get very hot and accumulate heat, and at night they thaw it into the atmosphere. In winter, the air receives additional heat from building heating.
Numerous impurities in the air (dust, smoke, soot, etc.) slow down its cooling; however, they collect moisture, which contributes to the formation of raindrops. Therefore, the temperature in the city is slightly higher and precipitation is higher than in its surroundings.
The longest season is winter; it comes in the east of the region at the end of November, and in the west - at the beginning of December, with the establishment of snow cover and freezing on the rivers. The first half of winter is characterized by unstable cyclonic weather with frequent thaws.
Due to the low altitude of the sun, the short day and the lack of snow cover, the land at the beginning of winter is very cold. The sea air brought in by the cyclones also cools rapidly and reaches a state of saturation, the water vapor it contains condenses, which causes cloudiness and frequent fogs. During December there are 18-20 cloudy days and only 2 clear days.
The second half of winter in the Leningrad region is almost always much colder than the first. The sea air coming from the west becomes colder and less humid, and cyclonicity is weakened. As a result, cloudiness decreases, fogs are rare. At the same time, arctic air invades more often, sharply lowering the temperature.
Spring comes in the region at the end of March, when the snow begins to melt. In the western part of the region, the snow cover usually melts in the last days of March, in the east - in the first half of April. At the beginning of spring, the first birds arrive, the trees bloom.
Spring develops slowly, as it is influenced by large water bodies cooled during the winter. The average daily temperature above 0C is set in St. Petersburg in early April, but reaches +5C only at the end of April, and +10C in mid-May.
Cyclones are rare in spring, so the weather is relatively stable. The number of days with precipitation is small, and the cloudiness is less than at other times of the year.
Often, Arctic air masses invade the Leningrad Region. Cold snaps are associated with it, and sometimes long, as well as late, mainly night, frosts that occur in May and even in June. The end of spring coincides with the end of frosts.
Summer in the Leningrad region is moderately warm. Due to the predominance of continental air masses, cloudiness is in most cases small, especially in early summer.
In the second half of summer, clear and warm weather is increasingly interrupted by cyclones. They bring cloudy, windy and rainy weather. In years with strong cyclonic activity, such weather prevails throughout the summer.
In early September, autumn is already coming, frosts are becoming more frequent, leaf fall begins, but the weather still resembles late summer. This is the so-called Indian summer, quite warm and dry. Since October, the temperature drops rapidly, cyclones intensify, cloudy, cool, windy weather with drizzling rain and fog prevails, which persists into November. Cloudiness and humidity are at their highest during this time of the year. From the end of October and throughout November, snow repeatedly falls and melts. In the last days of November, the average daily temperature drops below 0C. It's the end of autumn.
The Gulf of Finland.
In the west, the Leningrad Region adjoins the Gulf of Finland of the Baltic Sea. At the western borders of the region, its width reaches 130 km, and in the so-called Neva Bay it is only 12-15 km.
The southern shore of the bay is mostly sandy, low-lying, and only in some places, where the glint rises directly to the sea, is steep. It is slightly indented, but forms three small bays: Narva Bay, Luga Bay and Koporsky Bay. Among the islands, the largest are Bolshoy Berezovy, Western Berezovy, Northern Berezovy, Vysotsky, Powerful and Kotlin, on which Kronstadt is located.
The northern shore of the bay is composed of crystalline rocks: it is strongly indented and has numerous bays and granite rocky islands, the so-called skerries, separated by narrow straits. The most significant of the bays in the north is Vyborg.
The Gulf of Finland is shallow, its eastern part is especially shallow. The depth of the Neva Bay is 2.5-6 m, and in the coastal strip - up to 1 m. For the passage of ships along the bottom of the Neva Bay, a sea channel has been dug.
The salinity of the waters of the Gulf of Finland is about 0.6%, that is, lower than in the low-salinity Baltic Sea, which is explained by the large influx of fresh water from the rivers, especially from the Neva.
Due to the shallow water surface water temperature in summer is almost the same as the air temperature (for example, in July-early August 16-17C). Ice usually forms in the bay in December and stays until April (average 110130 days).
Fishing is carried out in the Gulf of Finland in spring and autumn.
Rivers.
Almost the entire territory of the Leningrad Region belongs to the Baltic Sea basin. The exception is the extreme eastern part of the region, which lies southeast of the watershed Vepsian Upland; it belongs to the Volga basin.
The river network of the Leningrad Region is dense and branched. Among the numerous rivers, the largest are the Neva, Svir and Volkhov. All of them flow in the lowlands, which in the past were occupied by glacial reservoirs. After the decline of the waters, the reservoirs separated from each other, but the straits connecting them remained. Later, these three rivers were formed from them, which even now are essentially canals-channels between large lakes (Ladoga, Onega, Ilmen) and the Gulf of Finland.
The Neva is a very short river (its length is only 74 km), but it is of great importance as the most important transport route connecting the Baltic Sea with the deep regions of the European part of Russia. Through the Neva, water enters the Gulf of Finland from a huge area of the entire basin of Lake Ladoga (281 thousand square kilometers). In this area, the amount of precipitation exceeds evaporation, so the Neva is very rich in water; in terms of water content, it is in 4th place in Russia. The annual water flow in the Neva is 77 cubic kilometers (an average of 2500 cubic meters per second).
Flowing among the plains of the Neva lowland, the Neva has low banks (5-10 m) and a total drop of only 4 m. Only in one place, in the middle reaches, near the village of Ivanovskoye, the river crosses the moraine ridge and forms rapids. The speed of the current in the upper reaches reaches 7-12 km / h, and in the lower reaches it drops to 3-4 km / h.
The Neva is a deep and wide river, even sea vessels enter it. Its greatest depth - 18 m - in St. Petersburg, near the Liteiny Bridge. The greatest width of the river is about 1200 m (at the source), the smallest is 240 m (at the rapids).
The Svir River has a length of 224 km, originates in Lake Onega and flows into Lake Ladoga. There were rapids in the middle reaches of the river, but after the construction of power plants on the Svir, the dams raised the water level, flooding the rapids and creating a deep waterway along the entire length of the river. The Svir has two significant tributaries, the Pasha and Oyat rivers, used for timber rafting. The flow of water throughout the year is regulated by Lake Onega, therefore, like the Neva, it is distinguished by a uniform regime.
The Volkhov River flows out of Lake Ilmen and flows into Lake Ladoga. The length of the river is 224 km, and the width in the upper reaches is about 200-250 m. In the lower reaches of the river, when it crosses the klint, rapids were formed. As a result of the construction of the Volkhovskaya HPP dam, the rapids were flooded. Feeding, like the Svir and the Neva, on lake waters, the Volkhov nevertheless has, unlike these rivers, an uneven regime. This is due to sharp fluctuations in the water level of Lake Ilmen, the volume of water in which is less than the amount of water poured into it by rivers. During the spring flood on the Volkhov, a sharp rise in water occurs, associated with the flow of melt water into Ilmen.
In addition to Volkhov and Svir, two more large rivers flow into Lake Ladoga - Syas and Vuoksa.
The Xiaxi basin covers the eastern part of the region; through the Tikhvin navigable canal, crossing the watershed, it connects with the Volga basin.
Vuoksa begins in Lake Saimaa, and its upper course is in Finland. Near the border with Russia, the river forms the famous Imatra waterfall. Two large hydroelectric power plants have been built on Russian territory in the rapids of the Vuoksa. In the lower reaches, the river consists of small lakes connected by short channels.
Among the numerous rivers flowing into the Gulf of Finland on the southern coast, the most significant are the Luga with the Oredezh tributary and the Narva with the Plyussa tributary. The Luga basin covers the southwestern part of the region and includes 350 rivers with a total length of 350 km. In the upper reaches of the river, the banks of the river are low and swampy; in the middle and lower reaches, they are high and steep.
The Narva flows out of Lake Peipus, flows along the border of the Leningrad region with Estonia and flows into the Baltic Sea. A large hydroelectric power station has been built in the lower reaches of the Narva; with the construction of the hydroelectric dam, a large reservoir was formed and the famous Narva waterfall disappeared.
The rivers of the Leningrad region, with the exception of a few flowing from large lakes, are fed by snow, rain and groundwater. They are characterized by spring floods with a sharp rise in the water level associated with the melting of snow. In summer and winter, when the rivers are fed mainly by groundwater, their level is low. In autumn, sometimes in summer with prolonged rains, there are floods with a significant rise in water.
All rivers of the Leningrad region are covered with ice at the end of November - in December. The ice reaches its maximum thickness in March. The rivers usually break up in April, but in some years - in May.
Rivers of the Leningrad region:
| river name | Length (km) | Bass area seina (t.sq.km) |
|
| General | In area | ||
| Neva | 74 | 74 | 218,0 |
| Svir | 224 | 224 | 84,0 |
| Oyat | 266 | 211 | 5,2 |
| Volkhov | 224 | 112 | 80,2 |
| Vuoksa | 156 | 143 | 68,7 |
| meadows | 353 | 267 | 13,2 |
| Oredezh | 192 | 192 | 3,2 |
| syas | 260 | 190 | 7,3 |
| Pasha | 242 | 242 | 6,7 |
Lakes.
There are more than 1800 lakes on the territory of the Leningrad region. The largest of them - Ladoga and Onega - are the remains of vast glacial reservoirs. They only partially lie within the area.
Lake Ladoga is the largest freshwater lake in Europe; its area is 17.7 thousand sq. km. The average depth of the lake is 50 m, and the largest is 225 m (to the north of Valaam Island). The northern shores of the lake, rugged, high and rocky, are composed of crystalline rocks. They form numerous peninsulas and narrow bays, small islands separated by straits. The southern shores of the lake are low, swampy, and the bottom near them is almost flat. The total volume of water in the lake is 900 cubic km. This is 13 times more than is annually poured into it by all rivers and carried out by the Neva. Therefore, fluctuations in the water in the lake during the year are small. There are frequent disturbances on the lake; with strong winds, waves reach 2 m or more. Due to these disturbances, small river vessels could not navigate the lake, and special bypass channels were built for them along the southern coast; some of the ships pass through them even now. Ice forms on the lake in late October - early November, first in shallow places; more areas freeze later - at the end of December, in January, and the central part freezes only in very severe winters. The melting of ice begins in March, but the lake is completely cleared only at the beginning of May. Due to the long and strong winter cooling, the water in the lake remains very cold even in summer, warming up only in a thin upper layer and near the coast.
Onega is the second largest in Europe (the area is about 9.9 thousand sq. km).
Most of the small lakes in the Leningrad Region are of glacial origin; many of them were formed during the melting of ice blocks left after the glacier. These lakes are located in depressions between moraine hills, usually have a round or elongated shape and shallow depth. Some lakes are flowing, others drainless. Lakes that do not have a runoff gradually become swampy.
Lakes of the Leningrad region:
| lake name | Area, sq. km | Naib. depth, m |
| Ladoga | 17700,0 | 225 |
| Onega | 9890,0 | 110 |
| Vuoksa | 95,6 | 24 |
| Otradnoe | 66,0 | 27 |
| Sukhodolsk | 44,3 | 17 |
| valye | 35,8 | 9 |
| Samro | 40,4 | 5 |
| Deep | 37,9 | 12 |
| Komsomolskoe | 24,6 | 20 |
| Balakhanovskoe | 15,7 | 12 |
| Cheremenets | 15,0 | 32 |
| vrevo | 12,0 | 44 |
| Kavgolovskoye | 5,4 | 5 |
The groundwater.
Groundwater is of great importance in human life as a source of water supply. They are especially important in those places where there are few rivers and lakes.
Groundwater is formed by infiltration of atmospheric precipitation into the soil in the water-resistant layer, as well as in cracks and rocks of sedimentary rocks. Underground waters are fresh and manipulative.
Most of the territory of the region is sufficiently provided with fresh groundwater. The depth (power) of the groundwater layer in most areas is 100-200 m, and the flow rate (amount of water) of wells is from 1 to 5 liters per second.
Most underground fresh water is in the elevated areas of the Karelian Isthmus, Izhora and Vepsovskaya Uplands. The thickness of the groundwater layer in these areas often exceeds 200 m, and the flow rate of wells is 5-10 liters per second. There is less fresh groundwater in the lowlands of the Prineva, as well as coastal ones along the southern shores of Lake Ladoga and the Gulf of Finland.
Vegetation.
The Leningrad region is located in the forest zone, in the south of the taiga subzone, at the point of its transition to the mixed forest subzone.
The vegetation cover that existed on the territory of the Leningrad region before the glaciation and during the interglacial period was completely destroyed by ice. With the retreat of the glacier, vegetation reappeared. First, in a cold climate, tundra vegetation arose. Later, when the climate warmed up, forests spread within the Leningrad region, initially pine, birch, spruce, and then oak.
Later, 4-5 thousand years ago, when the climate became colder and wetter again, oak places receded to the south, and spruce forests took their place. However, even now in the area you can find some elements of once existing broad-leaved forests.
Several centuries ago, the entire territory of the Leningrad region was covered with forest. Random forest fires, systematic burning of forests for arable land and their predatory felling have greatly reduced the forest area. Great damage to forests was inflicted during the Great Patriotic War. Now only about half of the region's territory is under forest. Higher forest cover in the north and northeast; in the central regions and especially in the south-west of the region, large areas are already treeless.
Coniferous forests are of the greatest importance: the main species in them are spruce and pine.
Spruce forests (forests dominated by spruce) usually grow on clayey and loamy soils, less often on sandy loamy soils. On elevated places with drained soils, green moss spruce forests grow, in the ground cover of which green moss predominates, and in herbaceous shrubs - oxalis (on rich soils), lingonberries (on poorer, but drier soils), blueberries (on wetter soils) .
The best spruce wood is given by sorrel spruce forests and lingonberry spruce forests. The wood is worse in long-moss spruce forests (with a cover of moss-cuckoo flax) growing in low and humid places, and the worst is in sfang spruce forests (with a cover of peat moss-sfangum), in wetlands.
Pine forests (forests with a predominance of pine) most often grow on sandy and sandy loamy soils, less often on loamy soils. On the slopes of sandy hills (kams and ozes) and on plains with dry sandy soils, there are white moss pine forests with a ground cover of lichen and green moss pine forests with a cover mainly of cowberry. These forests produce the best quality timber.
Long-moss pine forests are common in lower places, and sfang pine forests are found along the outskirts of the marshes. In place of cut down and burnt spruce forests, either pine forests or small-leaved forests with birch, aspen, alder and willow thickets usually appear. Over time, spruce reappears in such forests. Being shade-tolerant, it grows well under the canopy of pine or small-leaved trees. Having reached the upper tier of the forest, the spruce shade light-loving trees, they gradually die, and the spruce forest is restored. This restoration process takes quite a long time, so there are many spruce-small-leaved and spruce-pine forests in the region.
In the west and south-west of the region, permanent small-leaved forests and even small groves of oak, linden, aspen, mountain ash and other trees are occasionally found.
In many forests of the Leningrad region, timber is being harvested. Proper organization of forestry requires rapid reforestation, especially of industrially important species - spruce and pine. For this purpose, seedlings are grown in special forest nurseries, which are then planted in clearings.
Forests serve as a place of rest for people - they have sanatoriums, rest houses, pioneer camps, conduct excursions and hikes. Green zones have been created around St. Petersburg and other cities in the region. In them, as well as in the water-protective forests along the rivers and in the so-called forbidden strips along the railways, industrial felling of wood is prohibited; to clear and improve the forest, only a few overmature and diseased trees can be cut down.
The green zone of St. Petersburg includes forests within a radius of 60 km from the city. It also includes forest parks and parks. Of the numerous forest parks in the green zone of St. Petersburg, the largest are Nevsky on the right bank of the Neva, Central resort in Zelenogorsk, Severo - Primorsky in the Olgino-Lisy Nos area. The environs of St. Petersburg are famous for their historical parks - in the past, palace estates; most of them were created in the 18th century. Together with forest parks, they surround the city from all sides. The most remarkable among them are the parks of Petrodvorets, Pushkin, Pavlovsk, Lomonosov, Gatchina and Strelna. In St. Petersburg and its suburbs, forest parks occupy an area of 5.3 thousand hectares, and parks - 3.8 thousand hectares.
Almost all meadows were formed on the site of forest clearings, sometimes on abandoned arable lands, only some floodplain meadows are indigenous.
The meadows are used as pastures and hayfields. They require constant soil loosening, grass overseeding, drainage, and sometimes fertilizer application. In the absence of care, the meadows become overgrown with shrubs and swamp.
The best hay is provided by floodplain meadows, as well as upland meadows, moistened only by atmospheric precipitation. They grow cereals and legumes.
A significant part of the region's area (about 15%) is occupied by swamps. Many swamps are formed as a result of the overgrowth of lakes. Part of the swamps appears as a result of land swamping. This happens most often in forests on impermeable soils, in low places, with poor drainage. Sometimes swamps are formed after the destruction of the forest due to an increase in the level of groundwater and an increase in soil moisture.
At the beginning of their development, swamps are usually low-lying. They feed on groundwater rich in mineral salts, and their vegetation is dominated by sedges, horsetails, reeds, and often shrubs and squat trees (willow, black alder, aspen, etc.). As the swamp develops, peat grows, ground nutrition is replaced by atmospheric. Atmospheric waters contain few mineral salts necessary for herbal plants, so herbal vegetation is gradually being replaced by sphang mosses. Thus, the lowland bog turns first into a transitional grass-sphang, and then into a raised bog with a predominance of sphang moss. In swamps, cranberries and cloudberries grow in large numbers.
In the Leningrad region, raised and transitional swamps are more common.
The main wealth of raised bogs is peat. Transitional and relatively rare lowland bogs are sometimes used as pastures and hayfields; after draining and liming, they can be used for arable land.
Animal world.
The economic activity of people greatly affected the composition of the fauna of the Leningrad region, the number of animals and their distribution. The fauna of the sparsely populated northern and northeastern regions of the region is much richer than the more developed western and southwestern regions, and even more so the environs of St. Petersburg.
The Leningrad region is inhabited mainly by forest animals, among them 58 species of mammals. The squirrel, which is especially common in spruce forests, is of the greatest commercial importance: 100,000 squirrel skins are harvested annually in the region.
Often there are a fox, a polecat, a hare, a marten, a mole, various rodents (field and forest mice, a rat, etc.), less often a wolf, a bear, a lynx, a weasel, an otter. Lots of moose in the area.
A raccoon dog, a mink, a muskrat were brought to the region. Now these valuable animals have multiplied and are of great importance in the fur farming of the region.
There are also many birds in the Leningrad region - about 250 species (grouse, hazel grouse, black grouse, geese, ducks, waders and others).
Only a few birds winter in the Leningrad region (raven, sparrow, tit, bullfinch, woodpecker); the majority leaves our region since the end of August. The last, at the end of October, thrushes fly away, they fly back at the very beginning of spring. The arrival of all bird species ends only at the end of May.
There are 55 species of fish in the waters of the Leningrad Region. Of marine fish, herring has the greatest commercial value. This small sea herring enters the eastern part of the Gulf of Finland in late spring and early autumn. Of the other marine fish, there are: Baltic (Revel) sprat, belonging to the genus of sprats (it is caught in the Narva Bay), cod, sea pike (garfish).
A significant role in the fishery is played by migratory fish that live in the sea, but enter the rivers for breeding.
The main migratory fish is smelt, which makes up 3/4 of the catch of the Neva River and the Neva Bay; in spring, she rises up the river, laying her eggs on the sandy bottom.
Anadromous fish also include salmon and trout. In the past there were many, but now their number is small. Unlike other anadromous fish, the eel spends most of its life in rivers, but spawns in the Atlantic Ocean (in the Sargasso Sea). Together with fish from the sea, lamprey, the lowest vertebrate animal of the class of cyclostomes, enters the Neva and Lake Ladoga for spawning. It is caught both in the sea (especially in the Luga Bay) and in rivers.
Among commercial species, whitefish is of great importance, which is caught mainly in Lake Ladoga and on the Volkhov River. Quite often, perch, pike perch, bream, roach, smelt (small smelt) are found in rivers and on Lake Ladoga.
An aquatic mammal, the seal, lives in Lake Ladoga, preserved from the era when there was a sea reservoir on the site of the lake.
Communication paths.
Railways play the main role in the transport of the Leningrad Region. Their total length on the territory of the region is 2.7 thousand km, that is, about 3.2 km per 100 sq. km. In the west of the region, the railway network is denser, in the east - more rare. A bundle of railways diverges from St. Petersburg in different directions, connecting with it all parts of the region.
In the western and southwestern parts there are railways from St. Petersburg to Ust-Luga (via Ligovo-Lomonosov), Ivangorod (via Gatchina, Volosovo, Kingisepp), Slantsy and Gdov (from the Weimarn station). The southern part of the region is crossed by railway lines going from St. Petersburg to Pskov (via Gatchina, Luga), Vitebsk (via Pavlovsk, Vyritsa, Oredezh), Novgorod (via Pavlovsk, Novolisino), Moscow (via Tosno, Lyuban). The railway St. Petersburg-Petrozavodsk-Murmansk (through Mga, Volkhovstroy, Podporozhye), to Budogoshch (through Mga, Kirishi) and Vologda (through Mga, Tikhvin) pass through the eastern and northeastern regions. Railways cross the Karelian Isthmus both in the meridional direction (St. Petersburg-Vyborg and St. Petersburg-Priozersk-Khiitola) and in the latitudinal direction (St. Petersburg-Ladoga Lake, Vyborg-Khiitola).
The most significant junction railway stations in the region, in addition to the St. Petersburg junction, are Mga, Volkhovstroy and Gatchina.
Water transport is of great importance for the region. The Neva River, Lake Ladoga, the Svir River and Lake Onega form part of the Volga-Baltic Waterway. The main ports along this route are Petrokrepost, Sviritsa and Voznesenye. Some rivers are used for local navigation (Volkhov, Luga, etc.). On many rivers, especially in the east of the region (Oyat, Pasha, Syas, etc.), rafting is carried out.
On the Gulf of Finland between St. Petersburg and Vyborg, local sea voyages are organized.
An extensive network of highways has been created in the Leningrad Region. In all districts of the region there is a regular bus service connecting the inner parts of the districts with regional centers and railway stations. From St. Petersburg, along the southern part of the region, a motorway runs parallel to the railway to Moscow (through Tosno-Chudovo to Novgorod). Highways go from St. Petersburg to Tallinn (via Krasnoye Selo - Kingisepp - Ivangorod), Vitebsk - Kyiv, Pskov (via Gatchina - Luga), Volkhov, Slantsy, Vyborg, Priozersk.
Districts of the Leningrad region.
| District name | Name of the district center | Railway distance from St. Petersburg |
| Boksitogorsky | Boksitogorsk | 245 |
| Volosovsky | Volosovo | 85 |
| Volkhovsky | Volkhov | 122 |
| Vsevolozhsky | Vsevolozhsk | 24 |
| Vyborgsky | Vyborg | 130 |
| Gatchina | Gatchina | 46 |
| Kingisepp | Kingisepp | 138 |
| Kirishi | Kirishi | 115 |
| Lodeynopolsky | Lodeynoye Pole | 244 |
| Lomonosovsky | Lomonosov | 40 |
| Luga | meadows | 139 |
| Podporozhsky | Podporozhye | 285 |
| Priozersky | Priozersk | 142 |
| Slantsevsky | Slates | 181 |
| Tikhvinsky | Tikhvin | 200 |
| Tosnensky | Tosno | 53 |
Minerals
The Leningrad region is relatively rich in various minerals. Their composition, occurrence conditions and placement of deposits are closely related to the geological structure of the region.
Bauxites (near the city of Boksitogorsk; ores are shallow and can be mined by open pit), oil shale (near the city of Slantsy; depth of occurrence is 80-300 m, mining by a mine method) and phosphorites (near the city of Kingisepp) are of the greatest industrial importance.
The Leningrad region has huge reserves of granite, limestone, brick and refractory clay, building and molding sand and other building materials, mineral paints. There are large sources of mineral waters (Polyustrovskiye carbonic in St. Petersburg, sulfur water in Sablino, sodium chloride in Sestroretsk). Granite is mined in the north of the Karelian Isthmus, where the ancient crystalline foundation comes to the surface. Limestones are widespread in the region. Depending on the times of formation, different properties. The ancient limestones that make up the Izhora Upland are very dense and break into large slabs. The most significant limestone deposits are concentrated in the area of the clint and in the area of the city of Pikalevo, in the east of the region.
More than 2,300 peat deposits have been discovered in the region. Peat reserves in the region exceed 17 billion cubic meters. The largest peat deposits are located in the lowland areas of the region, especially in the south and east.
Climate
The climatic conditions of the Leningrad region, as well as the whole other territory, are primarily affected by its geographical location, which determines the angle of inclination of the sun's rays to the surface and the length of the day, and, consequently, the income and consumption of solar heat.
In general, for the year in our latitudes, the difference between the inflow of solar heat and its consumption (for heating the earth's surface and air, for evaporating water and melting snow) is positive. However, the flow of solar heat throughout the year is uneven, due to large changes in the height of the sun above the horizon (at noon at 60 degrees N - from 6.30 "in December to 53 degrees in June) and day length (from 5 hours 30 minutes in December to 18:30 in June).
From April to October, the arrival of solar heat in the Leningrad Region exceeds its consumption, and from November to March, the heat consumption is greater than its arrival.
Changes in the ratio of solar heat input and output throughout the year are associated with seasonal temperature changes that affect all other elements of the climate.
The movement of air masses of various origins also has a huge impact on the climate of the Leningrad Region.
The number of days in a year with the predominance of maritime and continental air masses is approximately the same, which characterizes the region's climate as transitional from continental to maritime.
From the west, from the side of the Atlantic Ocean, humid sea air of temperate latitudes enters the territory of the region. In winter, it is warm and makes up for the lack of solar heat, causing thaw, rain and sleet. In summer, the arrival of this air causes rain and cool weather. Continental air from temperate latitudes enters the territory of the region most often from the east, but sometimes from the south and southeast. It brings dry and clear weather: warm in summer, very cold in winter.
From the north and northeast, mainly from the Kara Sea, dry and always cold Arctic air comes in, forming above the ice. Intrusions of this air are accompanied by the onset of clear weather and a sharp drop in temperature.
Arctic maritime air enters from the northwest. Compared to the air coming from the northeast, it is less cold, but more humid. In summer, masses of tropical air occasionally invade the territory of the region, humid sea air from the southwest and very dry, dusty air from the southeast; they bring hot weather.
Air masses often change, which is associated with frequent cyclonic activity (in St. Petersburg, about 40% of all days of the year are with cyclones). The consequence of this is the unstable weather characteristic of the Leningrad Region.
The average annual air temperature drops in the Leningrad Region from west to northeast from +4.5C to +2.0C. The coldest month in the region is January or February. The average January temperature in the east of the region is -10C, in the west -6C. In St. Petersburg, the average temperature in January is -7.5C, in February -7.9C.
The warmest month in the region is July. The average daily temperature in July in St. Petersburg is +17.7C; deviations from it within the region are small (+16C near the coast of Lake Ladoga, about +18C in the southeast).
Average monthly air temperature (in degrees Celsius):
The duration of the period with an average daily air temperature above 5C in the east of the region is approximately 160, and in the southwest - 170 days. The sum of average daily temperatures on days with temperatures above 10C is 1600-1800. The area is characterized by high cloud cover. During the year in St. Petersburg, on average, there are only 30 cloudless days. In winter there is a lot of cloudiness. This slows down the drop in air temperature, as clouds prevent the outflow of heat from the lower atmosphere. The least cloudiness is in spring and early summer, the most in autumn. The entire territory of the Leningrad Region is located in the zone of excessive moisture. Relative humidity is always high (from 60% in summer to 85% in winter). The average annual amount of precipitation, which is 550-650 mm, is 200-250 mm more than the amount of evaporating moisture. This contributes to the waterlogging of the soil. Most of the precipitation falls between April and October. The greatest amount of precipitation (750-850 mm per year) falls on the elevated parts of the region.
Average monthly rainfall (in mm):
Much of the precipitation falls in the form of snow. A stable snow cover lies for about 127 days in the southwest of the region and up to 150-160 days in the northeast. By the end of winter, the height of the snow cover in the northeast reaches 50-60 cm, and in the west, where thaws often occur, it usually does not exceed 30 cm.
The climate has some peculiarities. In summer, during the day, stone buildings, pavements and sidewalks get very hot and accumulate heat, and at night they thaw it into the atmosphere. In winter, the air receives additional heat from building heating.
Numerous impurities in the air (dust, smoke, soot, etc.) slow down its cooling; however, they collect moisture, which contributes to the formation of raindrops. Therefore, the temperature in the city is slightly higher and precipitation is higher than in its surroundings. The longest season is winter; it comes in the east of the region at the end of November, and in the west - at the beginning of December, with the establishment of snow cover and freezing on the rivers. The first half of winter is characterized by unstable cyclonic weather with frequent thaws.
Due to the low altitude of the sun, the short day and the lack of snow cover, the land at the beginning of winter is very cold. The sea air brought in by the cyclones also cools rapidly and reaches a state of saturation, the water vapor it contains condenses, which causes cloudiness and frequent fogs. During December there are 18-20 cloudy days and only 2 clear days.
The second half of winter in the Leningrad region is almost always much colder than the first. The sea air coming from the west becomes colder and less humid, and cyclonicity is weakened. As a result, cloudiness decreases, fogs are rare. At the same time, arctic air invades more often, sharply lowering the temperature. Spring comes in the region at the end of March, when the snow begins to melt. In the western part of the region, the snow cover usually melts in the last days of March, in the east - in the first half of April. At the beginning of spring, the first birds arrive, the trees bloom.
Spring develops slowly, as it is influenced by large water bodies cooled during the winter. The average daily temperature above 0C is set in early April, but reaches +5C only at the end of April, and +10C in mid-May.
Cyclones are rare in spring, so the weather is relatively stable. The number of days with precipitation is small, and the cloudiness is less than at other times of the year.
Often, Arctic air masses invade the Leningrad Region. Cold snaps are associated with it, and sometimes long, as well as late, mainly night, frosts that occur in May and even in June. The end of spring coincides with the end of frosts. Summer in the Leningrad region is moderately warm. Due to the predominance of continental air masses, cloudiness is in most cases small, especially in early summer.
In the second half of summer, clear and warm weather is increasingly interrupted by cyclones. They bring cloudy, windy and rainy weather. In years with strong cyclonic activity, such weather prevails throughout the summer.
In early September, autumn is already coming, frosts are becoming more frequent, leaf fall begins, but the weather still resembles late summer. This is the so-called Indian summer, quite warm and dry. Since October, the temperature drops rapidly, cyclones intensify, cloudy, cool, windy weather with drizzling rain and fog prevails, which persists into November. Cloudiness and humidity are at their highest during this time of the year. From the end of October and throughout November, snow repeatedly falls and melts. In the last days of November, the average daily temperature drops below 0C. It's the end of autumn.
"Beautiful waterfalls of the world" - Waterfall. Iguazu is located in South America. Iguazu. Eternity of the Universe - that's what Iguazu is. Fisht waterfall. Gadelsha. Wide and powerful waterfalls. Kivach. Angel in translation into Russian means. The best waterfalls in the world. Devil's throat. Angel. A beautiful legend is connected with the formation of waterfalls on the Suna River.
"Water land geography" - Groundwater. Permafrost. Lakes. Reservoirs. Lakes, underground waters, swamps, permafrost, glaciers. Features of salt and gas composition. Let us recall the origin of lake basins. Glaciers. What lakes prevail in areas with a humid climate. Blue eyes of Russia. Swamps. Russia can be safely called a country of lakes and permafrost.
"Lesson in grade 6 about groundwater" - Source - the beginning of the river. What conditions are necessary for the formation of groundwater? A watershed is a boundary separating neighboring river basins. Lesson goals. Parts of the river. Repeat. Plan for describing the river system. Significance and use of groundwater. Rivers. QUESTION 4. What type of groundwater is shown in the figure?
"Waterfalls of the World" - Fog can be felt even a few kilometers from the waterfall! A waterfall is a stream of water rushing or falling from a height. Niagara Falls. The most beautiful waterfalls in the world. Origin of the waterfall Water in a swift stream, Mine captivates the eye. Angel Falls is the highest free-falling waterfall in the world at 978 meters.
"Water on the surface of the Earth" - Text. Glaciers. Work with the textbook. Geography. Evil or good. Conditions for the formation of lakes. Performance. The difference between lakes by origin. Lakes. Permafrost. Swamps. The groundwater.
"Underground waters" - Karst caves, stalactites and stalagmites are the result of groundwater activity. Valley of Geysers. Scheme of the location of the main types of groundwater. Karst springs. Groundwater pollution. Groundwater treatment facility. Where aquifers intersect with the earth's surface, springs arise.
There are 12 presentations in total in the topic
The territory of the Leningrad region is located at the junction of two large tectonic structures. The northwestern part of the region belongs to Baltic Crystal Shield.
Formed rocks
Here, the so-called Archean Early Proterozoic rocks. The formation time of rocks, according to archaeologists, is more than 600 million years ago, it is believed that the rocks were formed as a result of volcanic eruptions.
In the Cambrian period, strata were formed sedimentary rocks: blue clays with interlayers of sandstones. Deposits of phosphorites and oil shales were formed about 400 million years ago during the Ordovician period. Limestone, bauxite and dolomite deposits were formed during the Carboniferous period. In the Quaternary periods, the relief of the region was finally formed, as scientists believe.
minerals
The territory of the Leningrad region is quite rich in minerals. Bauxites, shales, clay, phosphorites, sand, limestone- the main natural resources that are mined in this region. New types of raw materials are constantly being discovered: natural gas, finishing stone, bitumen, magnetite ores.
Mining methods
Bauxites are of the most importance in the production of raw materials in the Leningrad Region. These minerals are shallow, which made it possible to extract them open way. Oil shale and phosphorite, on the contrary, are mined mine method.
Building natural materials
Large reserves of building natural materials are contained in the bowels of the region. On the territory of the Leningrad Region there are huge reserves of such sought-after minerals as granite, brick and refractory clay, limestone, foundry sand. Granite is mined in the north of the Karelian Isthmus, most often it is used as a facing material in the construction industry. Limestone deposits are concentrated not far from the city of Pikalevo.
As well as
A huge number of swamps in the region determines the large reserves of peat, there are more than 2300 deposits.
Phosphate ores, oil shale, quartz glass sands are also mined here. The Leningrad region is famous for its blue Cambrian clays and thermal waters.
