книги / Минерально-сырьевые ресурсы Пермского края

Perm Krai belongs to the industrial developed re­ gions of the Russian Federation. Fuel industry plays the leading part in the structure of PK industry. Its share is 25.2% in the total volume of industrial pro­ duction, produced by large and middle-size enter­ prises. Chemical and petro-chemical industries (16.6%) are on the second place, the third —belongs to machine building (15.6%), the fourth —electric power industry (14.2%). The contribution of the rest branches of industry into the total output is consuderably less as compared to the first four men­ tioned branches. A share of the forest, wood pro­ cessing, wood pulp and paper industries amount to 7.0%, food industry is 5.7%, ferrous metallur­ gy — 5.0%, non-ferrous metallurgy — 4.1%. Con­ struction materials (1.6%) and light industries (1.1%) are less presented in the structure of indus­ trial production of the region. A share of the rest branches is 3.9%.

Fuel-raw-materials branches (fuel industry and electric power industry) make up about 40% of the total volume of industrial production.

The primary chemistry and the organic synthe­ sis industry present chemical industry. Unique en­ terprises of Russia are JSC «Uralkaly» (Berezniki city) and JSC «Silvinite» (Solikamsk city) produ­ cing potash fertilisers. JSC «Azot» (Berezniki) and JSC «Mineralnye udobrenia» (Perm) specialise in the production of nitrogen fertilisers and other chemi­ cal products. JSC «Galogen» (Perm) produces cool­ ants, fluorocarbon polymers, inorganic products etc. JSC «Sorbent» (Perm) is the leading Russian enter­ prise producing activated carbons and their items. Chemical industry is presented by such enterprises as JSC «Berezniki sodovy zavod», «Soda-Khlorat» Ltd., JSC «Beraton» (Berezniki), JSC «Henkel-Pe- mos» (Perm) and other. The largest chemical plant of orgenic synthesis, JSC «Metafrax» (Gubakha),

specialises on production of methanol, urotropin, polyamid, formalin, KF-resins etc.

The special place in the machinery building in­ dustry of the region is occupied by the enterprises of military-industrial complex, also producing va­ rious civil production. FSUE (Federal State Unitary Enterprise) «Permsky zavod «Mashinostroitel», JSC «Scientific-industrial company «Iskra», FSUE «Mashinostroitelny zavod im. Dzerzhinskogo», JSC «Motovilikhinskiye zavody» belong to this group.

Non-ferrous metallurgy specialises on production of titanium and magnesium, is located entirely in Berezniki-Solikamsk industrial centre (JSC «Avisma» in Berezniki, JSC «Solikamsky magnievy za­ vod» in Solikamsk), where it is combined with the mining-chemical complex.

The main capacities of the wood processing and furniture industries are concentrated in the settle­ ments situated on the banks of Kama and Votkinsk reservoirs. One of them is the basic in the country plywood producing plants —«Perm Plywood Facto­ ry» Ltd. (Uralsky settlement in Nytva district).

Several plants of wood pulp and paper industry work in Perm Krai (JSC «Solikamskbumprom» in Solikamsk, SE (State Enterprise) «Krasnokamsk fac­ tory of Goznak» and JSC «Wood pulp and paper fac­ tory «Kama» in Krasnokamsk, LLC «Vishersky WPPF (wood pulp and paper factory)» in Krasnovishersk, LLC «Permsky karton (cardboard)» in Perm and so on.

Production of construction materials plays a sig­ nificant role in the economics of Gornozavodsk dis­ trict, Krasnokamsk city, Kungur town and Kungur district. The light industry is generally presented in the industrial structure of Tchaikovsky town (silk production), Lysva town (jersey), Kungur town (footwear), Vereshchagino town (jersey), Kizeltown and Okhansktown (garment).

Agriculture of Perm Krai has principally the re­ gional significance. 390 agricultural enterprises, 2684 farms and land parcels of other population were engaged in agricultural production according to the data on January 1, 2004. The structure of agricul­ tural production according to the economy catego­

ries was the following: a share of the agricultural enterprises amounted to 44.6% of the total volume of production; land parcels of other population were 54.4%, farms - 1.0% (data of 2003).

In 2003 the agricultural objects amounted to 2.3 million ha or 14.6% of the total territory of Perm

Krai. Ploughed fields occupied 75.2% of the total area, fodder area — 22.8%. The distribution of ag­ ricultural lands on the regional territory is non-ho­ mogeneous. Over 80% of the sown areas are concen­ trated in the central and southern districts, hayfields and pastures predominate in the northern parts. Suburban agricultural zones are mainly de­ veloped within Perm and Berezniki-Solikamsk city agglomerations.

In 2003 the share of plant growing in the struc­

ture ol agricultural production of Penn Krai amoun­ ted lo 48%. The structure of sown areas was divided as following: forage crops — 52.7%, grain crops — 39.8%, potatoes — 6.0%, vegetables — 1.4%, indus­ trial crops — 0.1 %.

Wheat (42.8%) predominated in the structure of areas under grain crops. Barley (18.2%), oats (18.1%) and rye (16.8%) shared nearly equal parts. The por­ tion of the rest crops is insignificant (4.1%). Gross vield of crops amounted to 609.4 thou tons in 2003.

Transport system of Perm Krai includes railway, automobile, water, air and pipelines transport. The regional territory is crossed by two main lines of transcontinental significance: Moscow — Yaro­ slavl —Perm —Ekaterinburg —Tumen — Omsk — Vladivostok and Moscow — Kazan — Ekaterin­ burg — Kurgan — Omsk. An operational length of the railroads of common use is 1324 km, including electrified ones — 1107 km (83.6%).

Passenger trains pass Perm connecting Central, North-western, Volgo-Viatsky districts of the coun­ try with the Urals, Siberia and Far East; Moscow — with the capitals of Mongolia and China; Saint-Pe­ tersburg —with the capital of Kazakhstan.

36.0 million tons of cargo (70.8% of the total vo­ lume of cargo traffic, excluding pipeline transport) and 17.0 million passengers (2.4% of the total vo­ lume of passengers transportation) were carried by railway transport in 2003.

The federal highway Saint-Petersburg — Kirov — Perm —Ekaterinburg crosses Perm Krai. The terri­ torial roads are added to the federal highways. In general, the extent of Perm Krai roads in general use is 11 084 km, inch 10 648 km of roads with firm sur­ facing (96.1 %). The length of departmental roads is 10 635 km, out of which 5182 km of roads with firm surfacing (48.7%).

Buses and fixed-route taxis connect Perm with many settlements of Perm agglomeration, the ma­ jority of cities and towns of Krai, as well as with Syktyvkar, Omutninsk, Izhevsk, Votkinsk, Sarapul, Naberezhnye Tchelny, Nizhnekamsk, Ufa, Neftekamsk, Samara, Tolyiatti, Ekaterinburg, Krasnoufimsk, Cheliabinsk.

The Kama River, flowing on the territory of the Krai, is an important link of the united deep-water system of the European part of Russia. In its turn it is connected with the waterways of the European countries. Thus, the most eastern four river-ports

of Europe are situated in PK: two in Perm, one in Tchaikovsky and one in Berezniki. The lenght of waterways, served by internal water transport of general use services is 1518 km. In 2003 — 4.3 million tn of cargo (8.4% of the total volume of cargo traffic of the region, excluding pipeline tran­ sport) and 174 thou passengers (0.03%) of the total volume of passenger traffic were transported by water transport on a commercial basis.

Several Russian and international air-routes go through Perm. Direct air-routes connect Perm with Moscow, Samara, Krasnodar, M ineralnie Vody, Rostov-on-Don, Saint-Petersburg, Surgut, Nizhne­ vartovsk, Novosibirsk, Krasnoyarsk, Frankfurt-on- Mien, Erevan, Baku, Tashkent, Dushanbe, Khudjant.

Several large oil and gas pipelines of all-Russian and international significance cross the territory of PK. The export gas-line Urengoi — Pomary — Uzh­ gorod is one of them. Near 22% of oil and 53% of natural gas produced in the country are pumped over through the region.

Wireless communication occupies the largest part (35.9%) in the structure of communication service given by large and middle-size enterprises. In 2003 a share of city and rural (wire) communication was 27.8% of the total volume of services. The rest branches of communications were distributed in the following: inter-town and international phone com­ munication — 15.8%, postal — 8.6%, new types of electric communication service — 3.7%, documen­ tary electric communication — 3.7%, radio and TV — 3.2%, wire broadcasting — 1.3%. At the be­ ginning of 2004 a level of mobile connection was 16% for the total population of the region, and 21% for city population.

The number of post offices was 692 at the begin­ ning of 2004, and 98.7% of the total number of popu­ lation was covered by TV broadcasting and by radio­ broadcasting (radio station «Russia») — 98.8%.

tab, gold, diamonds, rare metals, non-o!e aw mate­ rial:.. as well as at assessing geo-ecological situation ot die territory. As a result of those works by the be - ginning of the 90s, several fields of native gold, tung­ sten, tin, semi-precious stones, diamonds, manga­ nese, fluorite had been studied sufficiently and reached a searching-estimation stage.

Since the beginning of 60s the geological studies ol mineral resources were in a very inten­ sive progress. As a result of these works the region appeared to be provided with the main types of con­ strue i ion materials, chemical raw materials, facing stones for a long time in future.

Purposeful hydro-geological explorations have been started on the territory of Perm Krai at the be­ ginning of the last century. In its first half hydrogeological explorations were connected with the examination and development of Verkhnekamsk salt deposit, coal fields of Kizel and the discovery of oil in Verkhne-Tchusovskye Gorodki. At the same time hydro-geological explorations of the regional level have been performed in the north of Perm Krai, as a result of which the characteristic of hydro-geologi­ cal conditions of the northern part of the Kama River basin have been obtained.

The main hydro-geological explorations of Perm region were performed in the second half of the 20th century. At that period the exploration of the underground waters of Verkhnekamsk salt deposit and Kizel coal fields was in progress.

In 1959—1964 hydro-geological surveys in scale 1 : 500 000 were executed. Survey covered the whole district except for the far north-western part that was mapped five years later. These works resulted in obtaining the general information about the re­ gularities of the underground waters abundance, conditions of bedding, resources and chemical com­ position of the underground waters.

In 1965—1992 the state hydro-geological survey in scale 1 : 200 000 covered the territory of the Krai except for the far north-western and eastern moun­ tain districts. In the process of survey about 1000 hydro-geological wells were drilled with the complete sampling of core and geophysical explorations, over 9000 springs had been investigated. The complexes and horizons that had been discovered before, were determined more precisely and detailed, new hydrogeological subdivisions had been distinguished, over 300 rich in water zones had been mapped, mineral medical-table and medical drinking subsurface wa­ ters, unknown before, were registered and described. 90 sheets of hydro-geological and hydro-chemical maps in scale 1 : 200 000 have been constructed.

A large factual material has been obtained as a result of searching-exploration works aimed at or­ ganising domestic-drinking water supply of the

following towns: Solikamsk, Berezniki, Kungur, Ocher, Okhansk, Ossa, Krasnokamsk and other set­ tlements places. Over 100 deposits of underground waters of domestic-drinking purpose have been explored.

Since 1963 in Perm Krai the systematic observa­ tions of an underground waters regime have been performed by the subdivisions of Perm Geological Prospect Survey Company, and from the beginning of the 90s — by FSUE (Federal State Unitarian En­ terprise) «Permgeolmonitoring». Along with that the environmental water control works for the pro­ tection of the underground waters from sapping and pollution have been fulfilled. These studies gave the data on the regime of underground waters in dis­ turbed and natural conditions, the status and the level of pollution of the underground and sur­ face hydrosphere under the influence of economic activities.

In hydro-geological explorations of the region, which is the classical district of karst development, works dealing with the karst waters investigation play a significant role.

Underground waters of deep horizons are studied by the institutes KO VNIGNI (now KamNIIKIGS) and PermNIPIneft. As a result of their work hydro-geological, hydro-chemical and hydrothermal conditions of Palaeozoic deposits of the lower hydro-geodynamic level have been deter­ mined. Mineral hydrogen sulphide, iodine-bromine and industrial waters occupy a special place in the subsurface-waters study. Their research has been started in 40—50s of the last century. In connec­ tion with the prospecting and exploration of oil deposits some investigations of the environmental protection against oil, oil products and brines pol­ lution are performed.

Large factual material on underground waters of the upper horizons has been obtained in the course of explorations connected with the projecting of Kama, Votkinsk and Verkhnekamsky reservoirs, as well as at the engineering-geological studies of VerkhneKamTISIZ.

Comprehensive and significant in volume stu­ dies of regional u n d e r g r o u nd waters allowed to per­ form a series of generalised works, resulting in obtaining the estimation ot the operational reserves and natural resources of fresh underground water. A series of hydro-geological maps in scale 1 : 500 000—1 : 1 500 000: location maps of agri­ cultural water-supply conditions, maps of opera­ tional resources of fresh and saltish waters, mine­ ral and industrial waters, maps of protection and pollution of underground waters, antropogenic in­ fluence on hydrosphere have been made.

In 1990—1995 Sylvensky Hydrogeological Crew

had developed a new legend of hydro-geological map in scale 1: 500 000. They compiled hydro-geo- logical per sheet map in that scale of the eastern outskirts of the Eastern-Russian composite basin of bed waters within Perm Krai and Sverdlovsk re­ gion. In 1998 hydro-geological map in the scale 1:500 000 compiled for a plain part of the region have been supplemented with a map of the moun­ tain part. The map has been compiled according to the existing procedures in hydro-geological stratifi­ cation and mapping, and meets the modern demands to the informational value of hydro-geological maps in the given scale.

Seismic exploration. On the territory of Perm Krai JSC «Permneftegeophisica» performs seismic explorations. They perform detailed 2D and 3D sei­ smic survey aimed at searching and prospecting the deposits of hydrocarbons (HC); execute regional ex­ plorations to study and revise the geological struc­ ture and reveal new perspective directions of geo­ logical prospecting works.

The degrees of Perm Krai territory exploration with seismic techniques are different for different parts of the territory. Lands occupied by the zone of the development of Kamsko-Kinelskoy system of troughs, covering the central and the southern districts, belong to well explored and studied. The overwhelming majority of known deposits are located there. The main unexplored perspec­ tive resources of HCs are concentrated on these lands, which occupy 30% of the territory of Perm Krai.

Insufficiently explored lands are those within the limits of which industrial deposits of HC have been discovered, lands, where some regularities and zones of oil and gas accumulations have been determined in general and the directions of search have been defined. But there are territories of significant area, where searching works have not been performed and the features of their geological structure have not been determined to a sufficient degree. These lands occupy 29% of the territory of Perm Krai. On the platform they include behind-reef places in the south-east of Bashkirsky arch and Bymsko-Kungur- sky basin, the larger part of Visimsky and Verkhnekamsky basins, Perm arch and Rakshinskoy saddle. In Pre-Ural foredeep these are the northern and the eastern districts of Solikamsk basin, the cen­ tral and the southern parts of Sylvensky basin.

The territories of Bashkirsky arch, Bymsko-Kun- gursky and Solikamsky basins, and Kosvinsko-Chu- sovskoy saddle are well-studied areas, investigated with seismic explorations and structural drilling. The seismic grid interval there is over 2 km in 1 km2, and the density of the structural wells is lwell per 1.7 km2 (Bashkirsky arch).

The territories considered as insufficiently ex­ plored and unexplored are the following Vychegodsky trough, Kama and Perm arches, Rakshinsky and Kolvinsky saddles, Verkhnepechorsky basin and the Zone of the Urals front folds. The seismic grid in­ terval there is less then 1.0 km/km2, and the densi­ ty of the structural wells is 1 well per 250 km2.

As a whole the insufficiently explored territories are the Western-Urals zone of folding, Vychegodsky and Kazansko-Kazhimsky troughs, the nor­ thern part of Kama arch which occupy a significant part of the territory of Perm Krai.

Gravity exploration. The extent of exploration of the territory of Perm Krai with gravity surveys is very low and uneven. The State gravimetric maps available today are 1 : 200 000 scale maps of the first generation that have been compiled on the basis of the survey materials of 50—70s with the grid of few gravity stations. These maps contain large parcels without gravity measurements. About 230 gravity surveys in different scales have been confirmed with documents of factual materials.

At the end of 50s of the last century gravity crews of Molotov State All-union Geophysical Ex­ ploration Agency (later — «Permneftegeophysica» agency) started the exploration of a gravity field’s type in scale 1 : 200 000. At the same time «Perm­ neftegeophysica» agency was performing the sys­ tematisation of the results of field measurements

within the centrai and the southern parts of Perm Krai by constructing State gravity maps of the lb'si generation in scale 1 : 200 000. In the northern part these works were performed by the Centra! geo­ physical trust. In the course of 20 years period va si areas have been covered by gravity survey in scale 1 : 200 000, generally .with walking routes. But large plots of several districts have staved unob­ served because of their inaccessibility. Besides the low technological capabilities of that period and the grid with few gravity stations did not allow to solve specific geological problems. By now the gravity maps in that scale of the northern, western and southern districts of Perm Krai still have all the defects mentioned above. Part of the areas has been re-surveyed by the Specialized Gravity crew № 4 of Bazhenovsky geophysical surveying company in 1980-1990.

First large-scale (1 : 10 000—1 : 50 000) areal gravity surveys were used in the northern part of Ufimsky plateau (1948), Kizel coal basin (1951), Upper-Kama salt deposit (1954), Saranovskoye chromite deposit (1957). Some reports include in­ formation of the earlier detailed surveys but the re­ sults of observations have not been preserved.

From the middle of 70s the main volume of gra­ vity measurements in scale 1: 50 000 accompanying or outstripping the geological survey works have been executed by crews of Bazhenovskaya Geophysi­ cal Surveying company, prospect works — by FSUE «Permrudgeophysica». The works were concentra­ ted mainly on the territory of the Folded Urals and performed with a goal of searching and prospecting of ore deposits, including the primary sources of dia­ monds. The efficiency of gravity survey in dia­ monds’ prospecting is proved bythe modern detailed surveys in scale 1:10 000, supervised by «Permgeologodobycha» Ltd., on the anomalous fields ex­ plored by the maps of the smaller scale.

In 1957—1993 in Solikamsk depression and the neighbouring territories (Western-Urals zone of folding, Kolvinskaya saddle etc.) JSC «Permneftegeophysica» performed complex seismic and gra­ vity surveys for searching and prospecting of oilperspective fields. Gravity works were conducted at seismic lines. Later these surveys were not approved as standard for constructing gravity maps in scale 1 : 50 000 because of the curvilinear of lines, irre­ gularity of measurement grid and bad coordination of surveys of different years.

Since 2000 the Mining Institute of the Urals Branch of the RF Academy of Sciences has been per­ forming the areal gravity surveys in scale 1 : 50 000

and 1 : 25 000 on the oil-perspective fields of Perm surveying has been initiated on the ter­ ri iories of Solikamsk, Sylva and Verkhnepechorsky

basins, Western-Urals zone of folding, Kosvinsko- Chusovskoy saddle, Kama arch and other districts. At the same time gravity surveying has been organized at the regional seismic lines.

The mostly explored with the detailed gravity sur­ veying technique field is the territory of the Upper- Kama salt deposit. In 1986—1990 Bazhenovskaya Geophysical and Perm Geologic Prospecting Survey­ ing companies have performed gravity survey in scale 1: 25 000—1 : 50 000 in its central and southern parts. FSUE «Permrudgeophysica» has surveyed the northern part of the deposit in 1990—1995. Thus to­ day practically the whole territory of that deposit has been covered with the gravity base in scale 1 : 50 000 and supplied with the standard gravity maps. Begin­ ning with the end of 90s the Mining Institute of the Urals Branch of the RF Academy of Sciences has been performing experimental detailed surface and surface-underground gravity measurements of that deposit.

On the whole Perm Krai has been provided with the gravity surveys suitable for perform ing of searching-prospecting geological works of different mineral resources only at 25—27%.

Magnetic exploration. First land magnetic sur­ veys were performed in 1936—1946 mostly on the territory of Pre-Ural trough. Since 30s on the terri­ tory of Perm Krai the regional land magnetic sur­ vey has been conducted by the Urals Geophysical Trust (UGT), the Scientific Geological Prospect In­ stitute (SGPI), Scientific-Research Institute of Earth Magnetism (SRIEM).

The new stage of aeromagnetic explorations was connected with the explorations of Saint-Petersburg Geophysical Survey Company (State Enterprise SPGSC) in 1985-1991, AIGS (All-Union Institute of Geological Surveying) «Rudgeophysica» in 1998— 1999 and FGU NPP «Geologorazvedka» in 1999— 2002. This stage is marked by the use of highsensitive equipment, including the airborne gam­ ma-ray spectrometers, photo charting and satellitederived positioning. As a result the magnetic field digital model of the Krai territory has been built, the classification of the territory has been made, the large lithosphere blocks of the Russian plate has been detected.

Electrical exploration. For the first time electri­ cal explorations were conducted in 1938—1949 with the purpose of investigating the plots of Kizel coal­ field. They were widely expanded in the period of

The territory of Perm Krai is situated in the north-eastern corner of the Russian plate and in the Middle Urals. In its northern part the granite gneiss basement of the Russian plate along Cherdynsky joint rift zone is joined with the early-Baikal shale basement of Timano-Pechorskaya platform forming Eastern-European platform. There are three large tectonic regions on the territory of Perm Krai: the platform, Pre-Ural depression and folded Urals. (Note of the chief editor —the term «Pre-Ural de­ pression» is used only by the author of this chapter and the chapter «History of the geological develop­ ment of the region». In all the other parts of Ency­ clopedia it is called Pre-Ural foredeep.)

Tectonics ofthe platform part. In the limits of the platform, the basement surface which is 1.6—2.0 km deep at Komi-Permyatsky buried arch is dipping in the southern direction up to the depth of 10 km and more in Kaltasinsky aulacogen formed of Riphean sediments. On Krasnokamsk-Gremiachinsk bowing it is located at 2.8—3.5 km deep, at Osintsevsky bo­ wing —at 3.0—4.0 km deep. In Preduralskaya depres­ sion («foredeep») the basement homoclinally dipping eastward from 3.5—4.5 km to the depth of 5.0— 7.5 km in the zone of front folds of the Urals. Ac­ cording to a character of gravity magnetic fields more ancient Archean-lower Proterozoic whitesea rock masses are determined: Komi-Permyatsky, Kama and Krasnoufimsky. They are soldered together by linear zones of karelid development. The basement has a block structure. It is complicated by the sys­ tems of fractures of different age of origin and acti­ vation.

Sedimentary mantle is represented by Riphean, Vendian, lower-Paleozoic, Devonian, carboniferous, Permian and Mezo-Cenozoic sediments. Its thickness varies from 1.6—2.0 km on the bowings of the base­ ment to 10.0 km and over in Kaltasinsky (OssinskoBirsky) aulacogen on the platform and up to 4— 7.5 km in Pre-Ural depression. Shifts of basement blocks occurring in the course of the geological de­ velopment history of Perm Krai caused the forma­ tion of the structural stages in the sedimenary man­ tle of Riphean, Vendian, Devonian-lower Triassic,

middle-Jurassic —Cretaceous and Cenozoic struc­ tural stages which are divided into separate structural levels. All this complicates the tectonics of the terri­ tory.

In regional extent the territory of Perm Krai ge­ nerally is confined to epicratonic part of the Eastern-European platform. So, Upper-Kama basin and Pre-Ural depression occupy its bigger part.

Upper Kama basin consists of several parts, as it is a heterogeneous and heteromorphous structure. By its size it can be named the syneclise. The basin overlaps Kaltasinsky aulacogen, Nemsky peak of North-Tatarsky arch (in Udmurtia), Chepetsky and Chermozsky saddles of the basement, Komi-Per­ myatsky arch, Kama arch (possibly with Predtimansky trough) and even Solikamsk basin of the Pre-Ural depression. Within the Upper Kama basin on the platform there are three main isolated zones which differ by structure and history of the geological de­ velopment and modern structure: BorodulinskoFokinskaya, Viatsko-Kama and Kamsko-Chyor- mozskaya. Viatskaya zone of swells (dislocations) is situated to the west from the depression close to the boundary with Kirov region and Komi Republic. Their swells’ amplitude a little bit is increasing up along the section that is caused by tangential stress. Below the swells’ zone a graben of basement is situ­ ated, planated by terrigenous Devonian and pre-De­ vonian. In general this rifting structure is called Kazansko-Kazhimsky aulacogen. Predtimansky (Vychegodsky) trough is significantly planated by Riphean which is absent at Komi-Permyatsky bu­ ried arch and Kama overlaid-buried arch.

On the territory of Perm Krai Perm-Bashkirsky arch is represented by its northern part distinctly expressed on the geological map by the absence of Tatars sediments. The arch consists of Perm and Bashkir (Karaidelskaya) peaks divided by Babkinskaya saddle. Large Kungur-Ufim sky bowing, morphologically expressed on the earth surface as Ufimsky Plateau, is distinguished in its south-eas­ tern part along the lower-Permian structural stage. On Carbon and lower-line sediments Kungur homocline is located in the place of that plateau. Perm-

Babkinskaya saddle u ansfe 's into homocline slope facing the Pre-Ural d e p r e s s i o n .

The eastern edge o f t h e platform with the roof of Artinsky sediments of lower Permian is associated mainly with the sharp facial replacement in the eas­ tern direction of the zone where the thick Sylven- sko-Sarginsky reefs are developed by the less po­ werful domanik bituminous clayey-carbonate sedi­ ments. But deeper this boundary disappears, and the platform homocline slope transfers into Pre-Ural de­ pression. In Perm Krai it is represented by the south­ ern part of Verkchne-Pechorskaya basin and by Solikamskaya and Sylvenskaya basins divided by Kolvinskaya and Kosvinsko-Chusovskaya saddles. In the south Sylvenskaya basin is separated from Ayskaya depression (Bashkortostan) by SuksunoMolebskaya saddle.

Genetically Pre-Ural depression is a structure of a over-laid type. Before the early-Permian age, in Sverdlovsk region and Bashkortostan till the My- achkovsko-later-Carboniferous, this territory to­ gether with the adjacent territory of the western «slope» of the Urals was developing under typical platform conditions. That’s why Pre-Ural depression in a form of «foredeep» (edge trough) is expressed only in lower-Permian structural stage. In the eas­ tern direction the less powerful domanikovidnye rocks are replaced by more thick and coarse-grained rocks forming (with lower-Permian reefs in the west) a litho-facial trench planated by Kungur evaporites. Even now it is by mistake termed by many geologists as «foredeep». As a result of subduction of the Rus­ sian and the Western-Siberian plates under the trench the sedimentary cover rocks and a basement are homoclinally submerging beneath the Urals rift (as well as in the eastern part of the platform).

The interpretation of the data of Mikhailovsky regional seismic profile (Sverdlovsk region) allows to determine that the Central Urals meganticlinory has been faulted on the lower carbonate rocks. It expands the oiland gas-bearing perspectives of nappe-overthrust zone of the Urals, which is the western and less metamorphic part of the WesternSiberian plate. An obduced part of this plate is com­ plicated with the narrow anticlines which are con­ fined to the western head parts of overthrusts. In the western direction rocks, exposed in the anti­ clinal cores, are younger.

Within the Pre-Ural depression and platform the sedimentary mantle is complicated with the swells

of tectonic (pre-fracture), tectonic-sedimentary (covering of upper-Devonian-Turney and late-Her- cynian reefs) and plastic injection (Kungur salts in the Solikamsk basin). They all are complicated with the local uplifts.

Tectonics of the Urals fold system. On the de­ scribed territory the Urals fold system is subdivi­ ded into the Western-Urals external fold zone and the Central-Urals uplift.

It is necessary to mention that the external fold zone and the Central-Urals uplift in different tectonic epochs presented the eastern edge of the EasternEuropean platform. The evidences are the thickness and composition of the sedimentary cover as well as a character of magmatic stoping complexes.

According to a modern conception generally based on the geophysical data, a crystal basement of the Russian and Tymanskaya plates consists of gra­ nite gneiss domes (Verkhnekamsky, Krasnoufimsky, Vyatsky and so on) which are situated among green­ stone linear zones of protogeosynclinal origin (Kam- sko-Vyatsky, Perm-Tchusovsky, Tymansky).

An age of basement rocks is Archean-early-Pro­ terozoic. Within the structure of the eastern out­ skirts of the Eastern-European platform a basement has been opened with fourteen wells. The biggest opened thickness of basement rocks is 216 m, mini­ mum depth of roof occurrence is 1819.6 m, maxi­ mum —3384.4 m.

Crystall basement represent a complicated com­ plex of undispersed (uncrushed) metamorphic and magmatic rocks of different genesis modified by laid secondary processes. They are presented by biotite plagiogneiss, granite gneiss, biotite-amphi- bolite gneiss, biotite hornblende and biotite-pyro- xene gneiss, amphibolites, broken intrusions of gabbro, gabbro-norites and granites. The biggest part of rocks had been processed (diaftorirovana) in the conditions of alkaline-silicic metasomatism. The absolute age of metamorphism is 1810— 1940±20 million years.

In the late-Precambrian platform’s basement has been destructed by aulacogens and grabens. Their formation had been escorted with intensive magmatism of alkaline-olivine-basalt and tholeiite compo­ sition, injection of differentiated intrusions of carbonatites of a platform type. In Paleozoic era the Caledonian-Hercynian geosyncline zone of Tagil- sko-Magnitogorsky trough had been «injected» into the eastern part of submeridian late-Cambrian rift. Possibly it had the original rift character as well, base­ ment’s destruction of which had brought to the for­ mation of oceanic crust with ophiolite complex.

Occurrence and development ot CaledonianHercynian geosyncline (rift zone on the oceanic crust) have brought to the reformation ot structurai plan of the Eastern-European platform. In the limits of its epicraton blocks the extensive Volgo-Urals anticlise with Verkhne-Kamskaya depression, KamskoBashkirsky mega-arch, Tatarsky uplift and KazanskoKazhimsky aulacogen have been formed.

Pre-Ural foredeep represents a big synclinal structure transfer from platform to fold Urals. A trough of compensatory type has been formed in the orogenesis period of the Urals structure. It is characterized by increased, compared to the Urals and platform parts, thickness of upper-Permian sedi­ ments with salt deposits.

Western-Urals outer fold zone is the western part of the fold Urals composed mainly with the rocks of middle-late-Paleozoic of Paleozoic age. Rocks of ear­ ly-Paleozoic and late-Proterozoic ages are expan­ ded on small areas within the limits of Poludovo-Kol- chimsky meganticlinory (meganticline) and along north-eastern edge of the zone. The zone width at the latitude of settlem ent Nyrob reaches 115 km, its value to the south does not exceed 30—

50 l:m. Modern structural plan of the territory has formed as a result of Hercynian tectogencsis, in the very active forms from the late-Ordo-

v/cian !il] early-Triassic. Rocks of late-Proterozoic — bile ! ; leozoic age have been collected into folds, whose limbs are often turned over to the west and complicated with overthrusts. Overthrusts’ stretch corresponds folds’ stretch. Horizontal displacement of allochthonous blocks comes up to 5—6 km.

Central-Urals uplift (CUU) composed of ancient pre-Ordovician formations covers central orogra­ phic zone and a fitting to it a part of the Urals wes­ tern slope. Within the described territory in the Cent­ ral-Urals uplift the southern part of LiapinskoIssovsky meganticlinory (meganticline), UlsovskoKoivinsky megasynclinorium and Kvarkushsko-Ka- mennogorsky meganticlinory (meganticline) are singled out.

In CUU the rocks of crystal basement are dipped mainly on the 4—6 km depths. Two large structural levels are singled out except the rocks of crystal base­ ment; the lower represented with pre-Ordovician rocks and the upper represented with Ordovician and lower-Silurian formations.

The main characteristic features of magmatism of the western slope of the Urals are close connec­ tion with the elements of platform ancient struc­ ture, synchronism of manifestation all over the re­ gion and neighbouring regions. As well as striking variety of magmatic rocks and their associations (complexes) both of the same and different ages, connected with different structures and blocks with­ in the limits of the same structure-formation zones. Such a variety of magmatic formations is a conse­ quence of heterogeneous structure of the western slope of the Urals.

The following stages of magmatism manifestation are differentiated: Archean — lower-Proterozoic, Riphean, Riphean-Vendian, Vendian-Cambrian, Cambrian-Ordovician, Devonian.

Early pre-Cambrian stage has been manifested in the formation of intrusive massifs and their belts in the central parts and along peripheral parts of granuliteand granite-gneiss domes and among linear protogeosynclinal zones. The characteristic combination of magnetic and gravity anomalies of a deep type allows to fix mostly distinctly the intrusive massifs of peripheral belts on the dome structures, which are identified with-Tuimazinsky gabbroanorthosite complex of the early-Proterozoic era.

Riphean stage has been intensively manifested along the whole western slope of the Urals. In the Northern Urals at that time the formations of ba­ salts and their tuffs of tholeiite structure have been formed. Riphean magmatism of the Middle Urals is characterized by the appearance of volcanic centres with the eruption materials of trachytic and trachy- tic-basalt composition which are quite rare in the Northern Urals. According to our conception lateRiphean magmatism has been mostly intensively manifested in the riftogeneous late-Riphean-Ven­ dian zone of the western slope of the Urals, adjoin­ in g to the Main Urals fractures at the east.

Vendian — early-Cambrian stage is represented in the North Urals with rare granite intrusions and large formation of sills, lense's, stocks and dikes of gabbro and dolerites with which dikes of pickrites are closely connected. According to chemical and petrographic peculiarities these rocks are analo­ gous to traps of the ancient platforms. In the Middle Urals this stage of magmatism is represen­ ted by the wide development of alkaline and mainly sub-alkaline complexes of alkaline-olivine-basalt formation. Among pikrites of effusive and intru­ sive facies varieties in lamproite slope and contai­ ning isolated diamond graines (up to 0.5 mm) and