The Zazhoginskoe field is one of the richest

Russia Russia (, , ), or the Russian Federation, is a List of transcontinental countries, transcontinental country spanning Eastern Europe and North Asia, Northern Asia. It is the List of countries and dependencies by area, largest country in the ...

n field of

shungite Shungite is a black and lustrous mineraloid that was first described from a deposit near Shunga village, in Karelia, Russia, from where it gets its name. Shungite can be low-carbon (5% C), medium-carbon (5-25% C) and high-carbon (25-80% C) perc ...

on the territory of the

Republic of Karelia The Republic of Karelia (russian: Респу́блика Каре́лия, Respublika Kareliya; ; krl, Karjalan tašavalta; ; fi, Karjalan tasavalta; vep, Karjalan Tazovaldkund, Ludic: ''Kard’alan tazavald''), also known as just Karelia (rus ...

General information

The Zazhoginskoe field is one of the largest fields of shungite rocks in the world. It is located on the outskirts of the village Tolvuya in

Medvezhyegorsky District Medvezhyegorsky District (russian: Медвежьего́рский райо́н; krl, Karhumäjen piiri) is an administrative district (raion), one of the fifteen in the Republic of Karelia, Russia.Constitution of the Republic of Karelia It is ...

of Karelia, 1.7 km from the shore of

Lake Onega Lake Onega (; also known as Onego, rus, Оне́жское о́зеро, r=Onezhskoe ozero, p=ɐˈnʲɛʂskəɪ ˈozʲɪrə; fi, Ääninen, Äänisjärvi; vep, Änine, Änižjärv) is a lake in northwestern Russia, on the territory of the Repu ...

, 5 km from a navigable bay. Shungite rocks were deposited around the northern part of Lake Onega and under the lake. The field consists of two: Zazhoginskoe and Maksovo. Developed areas of the field are located 2–3 km to the south of the village Tolvuya. The development of Zazhoginskoe field began in the early 1990s. The field has a size of 22 km x 11 km. On the territory of the deposit are located the village Tolvuya and several other villages, including abandoned. Layers of shungite rocks interspersed with

tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock cont ...

dolomite Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincor ...

and

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, p ...

. Within the Zazhoginskoe field are sills and

dikes Dyke (UK) or dike (US) may refer to: General uses * Dyke (slang), a slang word meaning "lesbian" * Dike (geology), a subvertical sheet-like intrusion of magma or sediment * Dike (mythology), ''Dikē'', the Greek goddess of moral justice * Dikes ...

of metadiabases and metagabbro. Thickness of the sills is typically less than 50 m, but at the upper base sills reach thicknesses of over 150 m. In general,

igneous rock Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main The three types of rocks, rock types, the others being Sedimentary rock, sedimentary and metamorphic rock, metamorphic. Igneous rock ...

s make up about 30% of the productive series. Rocks of the upper base felt weak

regional metamorphism Metamorphism is the transformation of existing rock (the protolith) to rock with a different mineral composition or texture. Metamorphism takes place at temperatures in excess of , and often also at elevated pressure or in the presence of chem ...

(initial stage

greenschist facies Greenschists are metamorphic rocks that formed under the lowest temperatures and pressures usually produced by regional metamorphism, typically and 2–10 kilobars (). Greenschists commonly have an abundance of green minerals such as chlorite, ...

). A significant part of the deposits developed with metasomatic replacement of primary minerals by

carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate g ...

sericite Sericite is the name given to very fine, ragged grains and aggregates of white (colourless) micas, typically made of muscovite, illite, or paragonite. Sericite is produced by the alteration of orthoclase or plagioclase feldspars in areas that hav ...

albite Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. It represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula . It is a tectosilicate. I ...

and

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...

. Currently 25 deposits have been identified and explored in varying degrees, containing from 0.2 to 58.0 million tons of high-carbon shungite rocks.

Chemical composition of the ores

Carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent In chemistry, the valence (US spelling) or valency (British spelling) of an element is the measure of its combining capacity with o ...

- 30% *

Quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...

- 45% * Complex

silicates In chemistry, a silicate is any member of a family of polyatomic anions consisting of silicon and oxygen, usually with the general formula , where . The family includes orthosilicate (), metasilicate (), and pyrosilicate (, ). The name is al ...

(

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...

chlorite The chlorite ion, or chlorine dioxide anion, is the halite with the chemical formula of . A chlorite (compound) is a compound that contains this group, with chlorine in the oxidation state of +3. Chlorites are also known as salts of chlorous ac ...

) - 20% *

Sulfides Sulfide (British English also sulphide) is an inorganic anion of sulfur with the chemical formula S2− or a compound containing one or more S2− ions. Solutions of sulfide salts are corrosive. ''Sulfide'' also refers to chemical compounds la ...

- 3% Rocks within the Zazhoginskoe field are sufficiently stable in composition. The sum (C+SiO₂) is in the range of 83 - 90%.

Economic evaluation of reserves

Using the method of A. I. Nijinsky, the identified reserves are valued at around 1,241 million US dollars.A. C. Barkhatov, C. A. Shekov. The basis for the valuation of mineral resources of Karelia. 2002, Petrozavodsk, 334 p. According to geologists, there are good prospects for discovery of new fields in the

Kondopozhsky District Kondopozhsky District (russian: Кондопо́жский райо́н; krl, Kondupohjan piiri) is an administrative district (raion), one of fifteen in the Republic of Karelia, Russia.Constitution of the Republic of Karelia It is located in th ...

, where the transport infrastructure is well-developed, in contrast to the district of Zaonezhye. The only developer of Zazhoginskoe field is CDD Carbon-Shungite.

References

{{Reflist * Mineral-raw material base of the Republic of Karelia. - Petrozavodsk, 2005. KN. 1. * Solovov C. K. Radioastronomie properties of composite materials on the basis of shungite rocks and structures of these materials, Diss. Kida. technology. Sciences., Petrozavodsk, 1990, 155 S.
Zazhoginskoe field

* ttp://webmineral.ru/deposits/item.php?id=1891 Minerals and fields of Russia Geology of Russia Karelia