IPC RAS is located in IGEM RAS building at the address:
119017, Moscow, Staromonetny Lane, 35, IGEM RAS
Tel.: +7 (499) 230-8405, Fax: +7 (495) 951-1587

HISTORICAL INFORMATION

REGULATION OF INTERDISCIPLINARY PETROGRAPHIC COMMISSION

GOALS OF IPC

PERSONNEL AND STRUCTURE OF IPC

PRINCIPLES OF IGNEOUS ROCKS CLASSIFICATION

PETROGRAPHIC FORMATIONS AND PETROCHEMICAL SERIES

HISTORICAL INFORMATION

Petrographic Committee was established on 6th of July, 1962 within Academy of Sciences of the USSR at Division of Geological-Geographical Sciences of RAS.

Chairmen:
1962-1975 – Afanas’ev G.D., Corresponding Member of RAS
1975-1982 – Academician Sobolev V.S.
Since 1982 – Academician Bogatikov O.A.
Scientific secretaries:
1962-1966 – Makeyev B.V., D.Sc.
1966-1969 – Krut’ I.V., Ph.D.
1969-1999 – Simon A.K., Ph.D.
1999-2000 – acting secretary Krasivskaya I.S., Ph.D.
Since 2000 – Kurchavov A.M., D.Sc.

REGULATION OF INTERDISCIPLINARY PETROGRAPHIC COMMISSION

1. General regulations

1.1.The Interdisciplinary Petrographic Committee at Division of Earth Sciences RAS (further – IPC) is being established by the Division of Earth Sciences RAS (DES RAS) upon coordination with the Ministry of Natural Resources RF and Ministry of Education RF.
1.2. The IPC is scientific consulting and coordinating body in the field of petrography and petrology on the territory of Russian Federation and is attached to DES RAS.
1.3. The IPC in its activity is guided by acting legislation of Russian Federation, statutes of Russian Academy of Sciences, resolutions of General Meetings of RAS and DES RAS, decisions and instructions of RAS Presidium and Bureau of DES RAS as well as by these Regulations.
1.4. The DES RAS performs control and general management of IPC activity.
1.5. The work of the IPC is headed by its Chairman and his Deputy Chairmen approved by Bureau of DES RAS.  Personnel of the IPC are approved by the DES RAS on presentation of the IPC Chairman. For conducting day-to-day work, the IPC assigns a Bureau of IPC from its personnel.

2. Main directions of the IPC activity

2.1. Participation, along with other divisions of Presidium and DES RAS, Ministry of Natural Resources RF and Ministry of Education RF in coordinating activity of Institutes, Universities, subject expeditions and field works in the field of theoretical and applied petrology and petrography, as well as in the field of the most effective application of results of these studies at regular investigations of geological structure, petrography and mineral resources of Russia (geological mapping, prospecting for mineral commodities).
2.2. Determination of first-priority directions for basic and applied petrographic studies on the territory of Russia.
2.3. Participation in creation of methodical and theoretical grounds of geological mapping of crystalline complexes, creation and testing of regional patterns of partition and correlation of these complexes.
2.4. Examination and approval of proposals for modernizing petrographic classification, nomenclature and terminology of magmatic and metamorphic rocks.
2.5. Definition of subjects and directions of work for National, regional and methodical conferences, symposia, seminars on petrography and petrology; foundation of organizing committees and participation in their activity.
2.6. Representation and participation in the work of the scientific-editorial councils considering and testing the National geologic maps of diverse scale, prepared to publication, in relation to crystalline rocks, their series and formations.
2.7. Administration of publishing the literature of petrologic-petrographic topics, its testing, participation in the work of editorial boards of journals and books on such themes.
2.8. Analysis of a state of investigations being conducted with the use of achievements and methods of petrography and petrology in the frames of federal, target scientific-technical and all-Academy programs executed in the institutions and agencies of Russian Federation.
2.9. Assistance to expanding international cooperation in the field of petrology.

3.The rights of the Committee

For performance of its basic functions the Committee has the right:
3.1. To get acquainted with a state of researches in the field of petrology and petrography in scientific and applied-research institutions of the Academy of Sciences, Ministry of Natural Resources RF and Ministry of Education RF; to participate in development and modernizing of  technique and testing of results of the state geological mapping in areas of development of crystalline rocks; to have the representatives in scientific-editorial councils responsible for  publication of state geological maps, in editorial boards of the editions related to problems of petrography and petrology; to request and receive from the organizations of the Academy of Sciences, the ministries and departments of the Russian Federation information and materials concerning the competence of the IPC; to carry out examination of results of the works executed on state, scientific, technical and Academy of Sciences programs related to petrography and petrology.
3.2. Directly approach the organizations and departments of federal and regional level concerning activity and expertise area of the IPC.
3.3. To prepare and offer proposals on development and initiation of Academy and interdepartmental programs, support of scientific petrographic schools or separate talented (especially young) scientists  and on other questions from expertise area of the IPC.
3.4. Financing of IPC activity is carried out by DES RAS, however the Committee has the right to involve for its work financing from various sources (national and international grants, business contracts, joint projects), and also from business structures, when these funds are involved for realization of the purposes stipulated by the present regulation.
3.5. The committee has the right to have its official correspondence form, and in case of need and expediency to be registered as the legal body with the acquisition of corresponding attributes (a seal, the bank account, etc.).

4. Personnel, structure and methods of work

.1. The structure of Committee includes Chairman, his Deputy Chairmen, the Scientific Secretary and Members of the Committee. For conducting day-to-day work, the IPC assigns a Bureau of IPC from its personnel.
 4.2. The personnel of the IPC include scientists and experts from the Russian Academy of Sciences, the Ministry of Natural Resources of the Russian Federation and the Ministry of Education of the Russian Federation. It may also include representatives of the academies having the state status, representatives of scientific and scientific-technical societies, and also scientists and experts from the CIS countries (with the right of advisory vote).
 4.3. Regulation and Personnel of the Committee and any changes in them should be approved upon presentation of Chairman of the Committee by decisions of Branch of Earth Sciences of the Russian Academy of Sciences upon coordination with the Ministry of Natural Resources and Ministry of Education of the Russian Federation.
 4.4. Day-to-day activity of the Committee is carried out by its Chairman, Scientific Secretary with assistance of the Bureau Members. Basic decisions are accepted by Plenums of the Committee and the All-Russia Petrographic Conferences that are convoked as the need arises.

GOALS OF IPC

Tasks of the IPC follow from Regulation and in a brief kind are reduced to the following:

The Interdepartmental Petrographic Committee is scientific and advisory and coordinating body in the field of petrography and petrology in territory of the Russian Federation. It  is created under the  Branch of Earth Sciences of the Russian Academy of Sciences and is based in IGEM RAS.

TheIPC participates in definition of priority directions of basic and applied petrographic researches in Russia, in development of methodical and theoretical principles of geological mapping of crystalline rock complexes, creation and approbation of regional patterns of  partition and correlation of these complexes, in consideration and approval of proposals on modernizing petrographic classification, nomenclature and terminology of magmatic and metamorphic rocks.

The IPC also participates in organization and formation of subjects and direction of works of National, regional and methodical meetings, symposia, seminars on petrography and petrology, it  is a representative in work of scientific-editorial councils on consideration and approbation of prepared for edition State geological maps of various scale, regarding crystalline rocks, their series and formations.

One of directions of the IPC activity is the organization of publishing the literature of petrologic direction, its approbation, participation in the work of editorial boards of journals and books on the given subjects.

PERSONNEL AND STRUCTURE OF IPC

1. Bogatikov, Oleg Alekseyevich – Chairman, Academician RAS, IGEM RAS. Moscow.
2. Kurchavov, Anatoly Mikhaylovich - Scientific Secretary, D.Sc., IGEM RAS,. Moscow
3. Vernikovsky, Valery Arnol’dovich – Corresponding Member RAS, the Institute of oil-and-gas geology and geophysics, Siberian Branch of RAS. Novosibirsk
4. Vladimirov, Alexander Gennadievich, D.Sc., the Institute of geology and mineralogy, Siberian Branch of RAS. Novosibirsk.                                                         
5. Gel’man Michael L’vovich – Ph.D., NESRI FEB RAS. Magadan.
6. Glebovitsky, Victor Andreyevich - Corresponding Member of RAS, the Institute of Precambrian Geology and Geochronology (IPGG) RAS, St.-Petersburg
7. Dobretsov,  Nikolay Leontievich - Academician of RAS, Institute of geology and mineralogy, SB RAS, Novosibirsk.
8. Kovalenko, Vyacheslav Ivanovich - Deputy Chairman of IPC, Academician of RAS,IGEM RAS, Moscow.
9. Kogarko, Liya Nikolayevna, Academician of RAS, V.I. Vernadsky Institute of Geochemistry and Analytical Chemistry of RAS, Moscow.
10. Kozakov, Ivan Konstantinovich, D.Sc., the Institute of Precambrian Geology and Geochronology (IPGG) RAS, St.-Petersburg.
11. Kononova, Victoria Abbasovna, D.Sc., Professor, IGEM RAS, Moscow.
12. Korikovsky, Sergey Petrovich, Corresponding Member of RAS, IGEM RAS, Moscow.
13. Koroteyev, Victor Alekseyevich, Deputy Chairman of IPC, Academician of RAS,  A.N.Zavaritsky Institute of Geology and Geochemistry, Ekaterinburg.   
14. Krasivskaya, Irina Sergeyevna, Ph.D., IGEM RAS,, Moscow.
15. Kulikov, Vyacheslav Stepanovich, D.Sc., The Institute of Geology, Karelian SC of RAS, Petrozavodsk.
16. Marakushev, Alexey Aleksandrovich, Academician of RAS, IGEM RAS, Moscow. 
17. Marin, Jury Borisovich, Corresponding Member of RAS, St.-Petersburg State Mining Institute, St.-Petersburg.
18. Makhlaev, Lev Vasil’evich, D.Sc., Professor, the Institute of geology of Komi SC of Urals Branch of RAS, Syktyvkar.                              
19. Mitrofanov, Felix Petrovich, Academician of RAS, The Geological Institute of Kola SC, Apatity, Murmansk region.
20. Moskaleva, Valentina Nikolaevna, D.Sc., VSEGEI, St.-Petersburg.
21. Polyakov, Gleb Vladimirovich, Corresponding Member of RAS, the Institute of Geology and Mineralogy, Siberian Branch of RAS, Novosibirsk.
22. Popov, Victor Sergeyevich, D.Sc., Professor,  The Moscow State Geological Prospecting University, Moscow.
23. Reverdatto, Vladimir Viktorovich, Academician of RAS, the Institute of geology and mineralogy of Siberian Branch of RAS, Novosibirsk.                                                        .
24. Rozen, Oleg Markovich, D.Sc. GIN RAS, Moscow .
25. Rudnik, Vyacheslav Alexandrovich, D.Sc. Professor, the Institute of Precambrian Geology and Geochronology (IPGG) RAS, St.-Petersburg
26. Ryabchikov, Igor’ Dmitrievich, Academician, IGEM RAS, Moscow.
27. Samsonov, Alexander Vladimirovich, D.Sc. IGEM RAS, Moscow    .
28. Sklyarov, Evgeny Viktorovich, Corresponding Member of RAS, the Institute of the Earth's Crust (IEC), Siberian Branch of RAS,  Irkutsk.
29. Sobolev, Nikolay Vladimirovich, Academician, the Institute of Geology and Mineralogy, Siberian Branch of RAS, Novosibirsk .
30. Fershtater, German Borisovich, D.Sc. A.N. Zavaritsky Institute of Geology and Geochemistry, Ekaterinburg.
31. Khomichev, Valentin Leonidovich, D.Sc., the Siberian Scientific Research Institute of Geology, Geophysics and Mineral Commodities (SNIIGGIMS), Ministries of Natural Resources of the Russian Federation, Novosibirsk.
32. Chernyshov, Nikolay Mikhaylovich, Corresponding Member of RAS, the Voronezh State University, Voronezh.                                             
33. Sharkov, Evgeny Vital’evich, D.Sc., Professor, IGEM RAS, Moscow.
34. Sharpenok, Lyudmila Nikolayevna, D.Sc., VSEGEI, St.-Petersburg.
35. Shatov, Vitaly Vital’evich, Ph.D., Deputy Director of VSEGEI, St-Petersburg. 
36. Yarmolyuk, Vladimir Viktorovich, Corresponding Member of RAS, IGEM RAS, Moscow.
Scientific Secretary of the IPC – Kurchavov, Anatoly Mikhaylovich, D.Sc., leading research associate, IGEM RAS, Moscow.
The assistant scientific secretary of the IPC – Girnis, Marina Vasil’evna.

Bureau of Interdepartmental Petrographic Committee

Structure of Interdepartmental Petrographic Committee

1. Section on regional petrography, classification and terminology of crystalline rocks. Chairman – Dr. Shatov, Vitaly Vitalievich.
2. Commission on relation of magmatism and ore-formation. Chairman – Academician Kovalenko, Vyacheslav Ivanovich.
3. Commission on physico-chemical and geodynamic petrology. Chairman – Academician Ryabchikov, Igor’ Dmitrievich.
4. Commission on volcanology and paleovolcanology. Chairman – Academician Koroteyev, Victor Alekseyevich.
5. Commission on formations and series of magmatic and metamorphic rocks. Chairman –Polyakov, Gleb Vladimirovich, Corresponding Member of RAS.
6. Commission on cosmic petrology, Chairman – Academician Marakushev, Alexey Alexandrovich.
7. Commission on petrophysics. Chairman -

Regional Petrographic Councils (RPC) of the Section on regional petrography, classification and terminology of crystal rocks:
1. Urals RPC. Chairman – Fershtater, G.B., Ekaterinburg.
2. North-West Russia RPC. Chairman – Kulikov, V.S., Petrozavodsk.
3. Central--European RPC. Chairman – Chernyshov, N.M., Voronezh.
4. North-Caucasian RPC. Chairman –Enna, N.L., Essentuki.
5. West-Siberian RPC. Chairman – Polyakov, G.V., Novosibirsk.
6. East-Siberian RPC. Chairman - Abramovich, A., Irkutsk .
7. North-East RPC. Chairman – Gel’man, M.L., Magadan.
8. Far-East RPC. Chairman – Sakhno, V.G., Vladivostok.
9. Komi RPC. Chairman – Pystin, A.M., Syktyvkar.

PRINCIPLES OF IGNEOUS ROCKS CLASSIFICATION

The Interdepartmental Petrographic Committee considers necessary suggest to scientific-industrial community of Russia a modern classification of magmatic rocks in such form that looks like the most expedient.
Necessity of such publication is dictated by aspiration to the greatest unification of scientific materials including publications and, in an even greater degree, by the beginning of a new stage of the investigation of the territory of Russia and its mineral resources, related to the program "GeoMap-200."
The History of creation of scientific petrographic taxonomy goes back to the last century, to classical works of Rosenbusch, Loevinson-Lessing and other founders of modern petrography-petrology. The IPC has started regular work in this direction 30 years ago, having created the special Commission on the nomenclature and terminology of magmatic rocks. The IPC on behalf of IPC and Department of Petrography (now - Laboratory of Petrography, IGEM RAS) have published its versions of "Classification" in 1969, 1971 and 1983-84. Last version of national classification has been approved by the IPC on December, 28th, 1994 and published in “Petrographic code ” in 1995. Each of the named versions made additions and changes in previous ones though basic principles of classification have not changed within last 15 years.
It is necessary to emphasize that, from the beginning of 70th , all work of the IPC have been carried out in close cooperation with the International Subcommittee on Systematization of Magmatic Rocks of the International Union of Geological Sciences (chaired by Prof. A. Streckeisen and Prof. M.J. Le Bas). Interosculation of ideas of various national schools, taking into consideration their proposals in creating the general international classification have certainly brought a great advantage to science and geological practice as a whole. It is possible to note with satisfaction an essential role of Russian proposals in final balance of opinions on many key questions.
Last version of the International classification was published abroad in 1997. In 1998 this version was published in publishing house "Nedra" in Russian under editorship of S.V. Efremova, Scientific Secretary of the Commission on terminology and nomenclature of the IPC, and under financial support of the Russian Foundation of Basic Researches (the RFBR project 96-05-78171).
The Named version substantially considers standards and features of Russian taxonomic works of last decades and consequently it can be considered as acceptable both for scientific and applied geological mapping works in our country. Besides, from year to year extending scientific cooperation in the field of petrology, the edition of bilingual petrologic journal and some other related bilingual journals (including electronic versions), more and more frequent translations of  Russian books and articles into foreign languages, - all this together forces us not to stand apart from the general development of petrographic investigations in the World, and on the contrary to be integrated in the general stream of knowledge.
Such are the reasons which have urged the authors of the present website to suggest for use in Russia (including the project “GeoMap-200”) the International Classification of Magmatic (Igneous) Rocks and the corresponding dictionary of terms.

 Main principles of modern classification of magmatic rocks

These principles have been formulated during more than thirty-year period of work (since 1968) of the Subcommission on systematic of igneous rocks of the IUGS. In its activity, the most active participation had the representatives of the IPC RAS, Professors V.S. Koptev-Dvornikov, O.A. Vorob’eva, N.P. Mikhaylova, and Dr.  S.V. Efremova. These principles consist in the following:
a) The basic classification of igneous rocks should be established on their mineral composition or a mode. If the mineral mode cannot be determined due to presence of glass or fine-grained structure of the rock then other criteria can be used, for example a chemical composition as on ТАS diagram.
b) The term “plutonic rock” is used for rock with the obviously crystalline texture where crystals can be perceptible with the naked eye. This type of rock, as scientists suppose, is formed on significant depth.
c) The term “volcanic rock” is accepted for igneous rocks with the aphanic texture which is presumably related to volcanic activity.
d) Rocks should be named according to what they are, instead of with what they, probably, were.
e) Any classification should correspond to natural relationships.
f) Classification should consider as much as possible historical traditions so that well proved terms, for example, a granite, basalt, andesite, etc. could not receive drastically new definitions;
g) Classification should be simple and easy in use;
h) All official recommendations should be used in English, and any problems of transliteration should be solved by members of the national commissions in their countries.

 Modal parameters of classification:
Modal classification of plutonic and volcanic rocks is based on relative proportions of the following mineral groups:
Q - quartz, tridymite, cristobalite;
A - alkaline feldspar, including albite (<An5);
Р - plagioclase (An5-An 100) and scapolite;
F - feldspathoids or foids, including nepheline, leucite, pseudoleucite, nosean, etc.
M - mafic and related minerals, for example mica, amphibole, pyroxene, ore and
accessory minerals (zircon, apatite, sphene), epidote, garnet, primary carbonate.
First four groups are felsic, the last one - mafic minerals.

The Nomenclature: the experts of different countries do not have basic divergences relative to root names of rocks (basalt, granite, diorite, etc.). But as they are insufficient for experts, the Subcommittee of the IUGS approves introduction of additional determinants (mineral, textural, chemical, genetic, tectonic, etc.) . For example, biotite or porphyry or postorogenic granite, etc. The use of additional determinants is regulated by a number of common rules.

Use of classifications. Not all magmatic (igneous) rocks can be classified reasonably at use only one system. Accordingly, the IPC RAS and the Subcommittee of IUGS (in view of the Russian offers) have developed some classifications, each being applicable to the certain groups of rocks. Certainly, the majority of rock types are covered by two most widespread classifications -plutonic and volcanic. However a series of specific rock groups exist, which are beyond usual chemical, mineral, structural and other parameters and are considered only within the limits of "special" classifications. In a real situation, in consideration of those or other groups, the experts are forced to be guided by existing classifications in the following sequences:
a) ”pyroclastic rocks and tephra” if there are real attributes of pyroclastic origin;
b) "carbonatites" if the rock contains more than 50 % of a modal carbonate;
c) ”lamprophyre rocks ” if rock is considered as lamprophyre, lamproite or kimberlite;
d) “melilite rocks ” if rock contains more than 10 % of melilite;
e) ”charnockite rocks ” if there is an assemblage of hypersthene + quartz alongside with perthite or antiperthite.
f) ”Plutonic rocks” (definition see above);
g) ”Volcanic rocks” (definition see above).
The last two groups of rocks make not less than 90 % from volume of all crystalline rocks by occurrence. Therefore it is expedient to draw attention to main principles of their classification.

Plutonic rocks. Classification is based on modal parameters and is divided into three parts:
a) If the M is less than 90 %, the rock is classified by its felsic minerals with the use of QAPF double triangle diagram;
b) If the M is more or equal to 90 %, the rock is ultramafic and should be classified by its mafic minerals;
c) If the mineral mode is not yet defined, it is possible to use a preliminary "field" classification.
For the use of QAPF classification, the modal amounts of these mineral groups should be known being recalculated to 100% sum without mafic minerals.
Volcanic rocks. Those volcanic rocks that can have volcanic origin and  possess rather fine-grained texture, are classified under the following pattern:
a) If the mineral mode can be determined, the diagram QAPF is used;
b) If the mineral mode cannot be determined, the TAS classification is used on the basis of chemical analyses (a bulk chemical composition of rocks);
c) If there is no mineral mode and chemical analyses, the simplified "field" classification is used.

The Literature. Researchers and experts requiring deeper knowledge of problems of magmatic rocks classification can take advantage of the following main (normative) editions on a problem:
Classification of magmatic (igneous) rocks and the dictionary of terms. Recommendations of the Subcommission on systematic of  igneous rocks of the IUGS. (Translation from English, ed. S.V. Efremova), Moscow: Nedra Publ., 1997, 248 p.
The Petrographic code (magmatic and metamorphic formations). It is approved by the IPC RAS on December 28th , 1994. St.-Petersburg: VSEGEI, 1995.
Magmatic rocks (classification, nomenclature, petrography), Pt. 1-2. O.A. Bogatikov – Chief editor. Moscow: "Science",.1985.

The dictionary of terms of igneous rocks <http://www.igem.ru/site/petrokomitet/slovar.htm>

Словарь терминов изверженных горных пород

PETROGRAPHIC FORMATIONS AND PETROCHEMICAL SERIES

O.A. Bogatikov, V.I. Kovalenko, A.A. Tsvetkov, V.V. Yarmolyuk, A.M. Borsuk, S.N. Bubnov. Magmatic associations, formations, series. // Magmatic rocks. Evolution of magmatism in the Earth’s history. Chapter 1. Мoscow: “Science”, 1987. P. 7-18.

 Magmatism along with other geological processes is the indicator of lithosphere evolution and of various geodynamic environments. This indicator role of magmatism is manifested in correlation of quite certain sets of magmatic rocks rather than their separate varieties or assemblages with certain geodynamic environments and stages of lithosphere evolution.
Petrographers for a long time are occupied by searches for such indicator sets of magmatic rocks, the researchers of different geological schools choosing different ways.
At defining of such sets, or assemblages, the Russian and Soviet petrographic schools have chosen first of all a way of formation analysis of magmatic rocks, and foreign - a way of defining the magmatic series. It does not mean, that the Russian school does not use "series" concept. A.N. Zavaritsky was the first to introduce the term “magmatic series” into domestic literature (1950). This term was and is widely applied by Russian researchers. In the foreign literature the concepts close to “magmatic formation” also are used, for example, it is possible to consider as those the concept of S and I types of granitoids (Chappell, White, 1974) widely circulating in the literature. Actually they are rather close to earlier defined by Soviet petrographers a granite-leucogranite and granodiorite-granite magmatic formations with some additions (distribution of rare elements and isotopes) important for genetic conclusions. Classification of geochemical types of plutonic rock massifs has been developed by domestic scientists for revealing indicator properties of potentially ore-bearing massifs of magmatic rocks, including geochemical types of granitoids, corresponding to S- and I types: standard, lithium-fluoric and granodiorite-granite ones (Kovalenko, 1973; Tauson, 1977).
Nevertheless the formational and serial approaches prevail in different petrographic schools. Recent magmatism, in more detail studied abroad, is described as a rule from magmatic series view point, and more ancient magmatism, whose study have been significantly contributed by domestic researchers, in a greater degree - from formational analysis position.
Comparison of both approaches until now remains debatable.
Magmatic formations represent a special case of geological formations. These two concepts partially overlap each other, as far as magmatic rocks quite often form the mixed assemblages comprising both igneous and sedimentary rocks. An example is formations of volcanic rocks which often lie in close connection with sedimentary and pyroclastic formations.
For the first time the term "formation" has been applied to magmatic rocks by F.Yu. Loevinson-Lessing at the close of XIX century.  The term “magmatic formation” (M.A. Usov, Y.A. Bilibin, G.D. Afanas’ev, I.V. Popov, etc.) and close to it “related group” (G. Tirrel), “magmatic association” (F. Turner, J. Verhoogen) were first applied to design associations of magmatic rocks interrelated by common origin. In Y.A. Kuznetsov and E.K. Ustiev's works other meaning of the term “magmatic formation” has been entered to imply that relationships between rocks in a formation not necessarily should be based on their genetic relationships, and can be more remote.
Domestic researchers allocated formations abstract (formational type) and concrete (N. Kheraskov, 1952). The abstract magmatic formation usually is understood steady, repeated during the geological evolution, natural association of magmatic rocks possessing a certain similarity of composition. This global taxonomic unit is not adhered to a particular region or structure.Yu.A. Kuznetsov (1964) insisted that in definition of such cardinal concept for geology as “magmatic formation” we cannot directly include those attributes that we cannot directly observe and study, for example, ideas about deep magmatic hearths, parental magmas, etc. Even earlier thees principles, at definition of “geological formation” concept, have been formulated by N.S. Shatsky (1945) and N.P. Kheraskov (1952), who considered a formation as a rock paragenesis. N.P. Kheraskov emphasized that genetic affinity of rocks observed sometimes inside of a formation is an attribute only hypothetical rather than universal.
A particular expression of formation type (of abstract formation) is the particular magmatic formation which was formed during a certain time (usually corresponding to a geological period or its  part) within the limits of separate region and reflecting specificity of one of stages of development of a separate structural-formational zone, of whose  set this region consists.
In a basis of defining a particular magmatic formation, the following criteria (A.M. Borsuk, 1977) usually are accepted:
1) similarity of petrographic, petrochemical and geochemical features of rocks;
2) unity of structurally-geological position, i.e. development within the limits of uniform large geostructure;
3) relation to a single stage of tectono-magmatic evolution of this structure. This definition of formation it is rather close to that developed by scientists of VSEGEI (Magmatic formations of the USSR, 1980). Even so, the concept of "formation" contains the material and structural features of magmatic rocks association which have arisen in certain geological environment being related to a certain geodynamic regime (Moskaleva, 1985).
Thus, different scientists a little differently treat the concept of "formation", however they converge in the main thing that it is the natural association of the rocks inherent in quite certain stage or a cycle of geological history
It is necessary to emphasize, that magmatic formations (unlike magmatic series) are allocated basically by petrographic features and their names reflect the names of specific kinds of rocks. It certainly does not mean that petrographers ignore petrochemical features of formations which also is their important attribute. Principles of defining magmatic formations, their contents and criteria of discrimination from other petrographic terms (associations, complexes, series, etc.) were repeatedly discussed at petrographic meetings and special symposia (Leningrad, 1968; Baku, 1969; Moscow, 1984, etc.).
In formational analysis of magmatic rocks, the  two directions of researches were distinctly designated.
One direction puts the task of revealing petrologic-geochemical features of formational types (abstract formations) of magmatic rocks, study of rock parageneses. This important direction is successfully developed by the school of Siberian geologists for many years headed by Yu.A. Kuznetsov (A.F. Belousov, A.P. Krivenko, E.P. Izokh, V.A. Kutolin, etc.). Works in this direction help to understand the mechanism of petrologic and geochemical processes resulting in creation of steady natural assemblages of rocks regularly repeated in different regions and during various geological epochs, revealing the dependence on type of tectonic structures and of the Earth's crust structures.
Other direction, which during many years was developed by G.D. Afanas’ev (1950, 1958, etc.) and his followers, is related to comparative analysis of specific magmatic formations formed during evolution of separate regions. Such researches allow determining variations in composition and formation environments of magmatic formations, arising synchronously or close on time within the limits of various structural-formational zones of a single large geostructure, and also of magmatic formations replacing each other in time during evolution of structural-formational zones composing the geostructure. The comparative analysis of particular magmatic formations enables to reveal specificity of tectono-magmatic development of separate regions and to define distinctions in evolution style of structures the same type.
Thus, if for the first direction it is the most important to determine typomorphic features of a natural assemblage, for the second one it is necessary to reveal specificity of this natural rock assemblage, characteristic for a particular geostructure and a particular stage of its evolution. Undoubtedly,   both directions cannot develop separately from each other.
The Doctrine of magmatic formations is developed on a junction between petrology and geotectonics as far as occurrence of this or that type of formation is related to a certain tectonic regime. Therefore the main task of the doctrine of magmatic formations is revealing relations of magmatism with the composition and structure of the Earth's crust and lithosphere as a whole, with the geodynamic regime intrinsic for this or that tectonic structure. The determination of these relationships finally helps the decision of genetic problems of magmatic rocks, their metallogenic specialization and their role it formation of modern appearance of the Earth. Study of natural rock parageneses enables to limit theoretical and experimental models of their origin to those realized in natural environments.
Now the big mess in understanding the concept of “magmatic rocks series” is marked. Alongside with traditional tholeitic, calc-alkaline and alkaline series, some narrower magmatic series of rocks are defined according to rocks prevailing in them - komatiite, shoshonite, andesite series, etc. Then, what we should understand as series of magmatic rocks?
Obviously, by analogy with magmatic formations, it is necessary to distinguish also abstract (serial type) and particular series. The abstract series is based on general petrochemical features of magmatic rocks assemblages and consequently can be named also petrochemical series. The classical triad of petrochemical series - tholeitic, calc-alkaline and alkaline - is defined on the basis of various petrochemical criteria, however, unfortunately, not always unequivocal for various authors.
As a special case of petrochemical series, apparently, we should consider petrographic, i.e. particular series of magmatic rocks, whose names consist mainly from names of petrographic varieties of igneous rocks (shoshonitic, boninitic, etc.). Really, petrographic series can enter into corresponding petrochemical series, for example, shoshonitic - into potassic subalkaline, and boninitic - into high-magnesium calc-alkaline. Thus, a particular (petrographic) series of magmatic rocks – is narrower notion. It is characterized only by inherent features of specific mineral and chemical composition, allowing to judge about genetic relationships of rocks from which it is composed. In essence, the particular magmatic series represent rock sets that have been formed under similar physical and chemical parameters, following by trends of differentiation of single parental magmas.
Naturally, defining of particular series is much more difficult than defining of abstract series. Difficulties of defining series of magmatic rocks can be easily shown on the following examples. Starting from works of H. Kuno, A. Ritman, J. Nockolds, A. Allen and A. Miyashiro, the three petrochemical series are usually considered: tholeitic, calc-alkaline and alkaline (alkali-basaltic). There is an extensive literature on this question. Features of composition of magmatic series are reflected in works of F. Turner, A. Ritman, H. Kuno, L. Wager, B. Deer, A.Sugimura, I. Katsui, W..Dickinson, J. Gill, P. Yakesh and A.White, А.А. Marakushev, collective authors of the monograph «Magmatic rocks» and other scientists.                                                           Tholeitic and alkaline magmatic series have been first defined only for the basic rocks. The following petro-geochemical distinctions of rock composition were more often accepted as criteria of their dividing: 1) mineral composition of a ground mass (Tilley, 1950); 2) normative mineral composition of rocks (Yoder, Tilley, 1965); 3) contents of Na2O and K2O (MacDonald, Katsura, 1964). At the same time, the calc-alkaline and alkaline series were divided by M. Peacock (1931) on the basis of values of acidic-alkaline index - so-called Peacock index [wt %  of SiO2, at which the wt % СаО = (Na2O+K2O)]; the series with an index less than 51 were treated as alkaline, from 51 to 56 – as calcium-alkaline, from 56 to 61 - as calc-alkaline and above 61 - as limy ones.
Thus, the tholeitic and calc-alkaline series were defined as less alkaline than alkaline series, i.e. were defined by G. McDonald and T. Katsura to a category of subalkaline rocks.
It is important to emphasize, that application of classification diagram SiO2 - (Na2O+K2O) (Kuno, 1959), as well as Q index of A.Sugimura (1968), allowed to distinguish only tholeitic and alkaline series rather than tholeitic and calc-alkaline. H. Kuno, for example, did not consider the calc-alkaline and peraluminous series as identical.
Tholeitic and calc-alkaline series have been reliably divided by L. Wager and V. Deer (1939) on the basis of distinctions in trends of enrichment of consecutive members of series in iron. These researchers have shown, that intensive enrichment of later magmatic differentiates in iron (for example, in the Skaergaard pluton) is characteristic for tholeitic series (Fenner’s trend), and absence of the iron enrichment trend - for calc-alkaline series (Bowen’s trend). More often and most clearly this law is illustrated on the AFM diagram. Quantitative criteria of dividing these series on the basis of data on AFM diagrams have been calculated by T. Irvin and V. Baragar (1971).
In the same way, the petrochemical distinction of calc-alkaline and tholeitic series is find out by analysis of (FeO+Fe2O3) - MgO diagrams (Jakes, Gill, 1970) or (FeO+Fe2O3) / (FeO+Fe2O3+MgO)-SiO2 (Osborn, 1959). For quantitative distinction of the rocks of tholeitic and calc-alkaline series, A. Miyashiro (1974) has applied the modified version of (FeO+Fe2O3) / (FeO+Fe2O3+MgO)-SiO2 diagram. From the data of K. Kuno and E. Osborn indirectly follows that tholeitic series are characterized by high speed increase of the iron to magnesium ratio with the growth of SiO2 contents in the rock. On the contrary, A. Miyashiro, T. Irvin and B. Baragar absolutely clearly defined tholeitic series as having high ratios of  FeO*/MgO relative to contents of SiO2 or (Na2O+K2O). Therefore for them the growth of iron content in consecutive differentiates in the composition of magmatic formations and groups of formations is not characteristic, and they have rather constant FeO*/MgO ratios for a wide spectrum of SiO2 values. Especially evidently it is shown for intermediate magmatic rocks, for example, for syenites.
H. Kuno who has made a big contribution to development of series concepts of igneous rocks, insisted that there are three basically different magmatic series: tholeitic, peraluminous and alkaline. He thought that the calc-alkaline series differ by hypersthene presence in the rock’s groundmass, have low FeO*/MgO ratios and can be formed at the expense of any other series. Therefore it is possible to affirm that hypersthene series of K. Kuno in which volcanic rocks contain the hypersthene in the groundmass, are synonymous to calc-alkaline series, and his pygeonite series with the presence only of clinopyroxene in the rock’s groundmass are analogues of tholeitic series.
Different authors spoke about various total Na2O and K2O content in rocks of tholeitic, calc-alkaline and alkaline magmatic series. K. Kuno (1968) such distinction of tholeitic and calc-alkaline series considered as unessential. He treated the iron enrichment and alkalis enrichment as two independent parameters and used only first of them for dividing tholeitic and calc-alkaline series. We shall note that H. Kuno’s scheme has not been accepted by the broad petrologic audience outside of Japan because of internal contradictions between mineralogical and petrochemical criteria of defining these series, difficulties with pyroxene identification in the groundmass and ambiguities of genetic relationships of the series.                                                    Later, P. Yakesh and J. Gill (1970) for the first time have lead a border between tholeitic and calc-alkaline series of island arcs using all chemical elements. They guessed that the main distinctive features of island arc tholeitic series from calc-alkaline are the lower Fe content, raised Na2O/K2O ratio, lower concentration of K and chemically close to it large cation lithophile elements (LILE). The K/Rb ratio reaches 1000, Th/U = 1-2, and REE are characterized by chondritic distribution with the La/Nb = 1-2. These authors believed, that the basalts of island arc tholeitic series occupy an intermediate position between basalts of calc-alkaline series and basalts of median-oceanic ridges and that the magmatic assemblages with low contents of LILE (incoherent) elements are simultaneously characterized by high FeO*/MgO ratios.
The term «island arc tholeitic a series» can be considered as quite reasonable and it obviously should be used for those series which, according to AFM diagram, are tholeitic.
J. Gill (1981) recommended to apply to dividing tholeitic and calc-alkaline series A. Miyashiro's (1974) criteria in spite of the fact that the term “tholeitic” may don’t mean progressive growth of iron content of the magmatic rocks belonging to this series.
Apparently, for classification of series, the A. Miyashiro's criteria, really, are most expedient, though they are somewhat optional, but the question itself is in general indisputable, because the rocks, that form tholeitic and calc-alkaline series, essentially differ geochemically. Besides, they are apparently different genetically even within the limits of the same volcano (Matsuda, Aoki, 1979).
Thus, the available classifications of petrochemical series have no uniform basis so far as the different authors put different sense in understanding of this or that series (especially tholeitic or calc-alkaline). In this connection the uniform basis of classification of series is necessary.
Available classifications of series do not define the subalkaline compositions of rocks which are distinct from tholeitic or calc-alkaline, that reduces indicator opportunities of magmatic series.
In classification of domestic petrographers the subalkaline series are presented (Classification …, 1981). In classification of petrochemical series it is necessary to consider a role of potassium as it is made for island arc series (Trondhjemites …, 1983; Andesites …, 1982), having distributed this attribute on all magmatic rocks. The indicator of the role played by potassium in this case is K2O/Na2O ratio, as it was accepted in the Soviet classification of magmatic rocks (Classification …, 1981), rather than K2O content in a rock.
Quite certain order of application of indicator attributes is necessary for classification of petrochemical series. At its absence, for example, high-potassium tholeitic series of J. Gill correspond by all parameters to alkaline rather than to tholeitic series.
The Main thing for classification of magmatic series is the definition of petrochemical series notion. Ideally, the petrochemical series includes an assemblage of magmatic rocks genetically related to processes of magmatic differentiation of a source. It means that all rocks of the series should have the constant ratios of isotopes (in particular, Sr, Nd, Pb) and incompatible (incoherent) admixture elements, and their concentration should vary within the limits restricted by genetic relationships. Thus, ideally the petrochemical and petrogenetic series should coincide. However it is frequent that this rule is not observed even within the limits of one volcano and even of one eruption (Gill, 1981). For example, the 87Sr/86Sr ratio in rocks of consecutive eruptions of Quolibou volcano on Santa-Lucia island sharply increases from 0,704 to 0,709, that is, probably, related to different sources of magmas of numerous eruptions of the volcano. There are many such examples of distribution of incoherent elements admixtures in rocks.                             It is not always possible to prove genetic relationships of rocks of one "series", in particular because the variations of compositions of rocks (including isotope) can be related to unknown yet mechanisms of differentiation, or to the absence of data on isotopes and on distribution of rare elements in rocks. Therefore, in the same way, as Ю.А. Kuznetsov objected to introduction of genetic notions into definition of magmatic formations, this attribute cannot be also entered into definition of petrochemical series of magmatic rocks. It does not mean, that we reject genetic relationships of rocks in petrochemical series. In each case such relationships should be proved or mentioned in the presumable form.
For unambiguous discrimination of defined series, it is important the arrangement (the order of application) main petrochemical parameters according to their indicator importance. Thus, on the basis of definition of tholeitic, calc-alkaline and alkaline series (Miyashiro, 1974),  it is necessary to subject a selection of chemical compositions of magmatic rocks to the following procedure:
1) separation of alkalinity series (alkaline, subalkaline, on the one hand, and normal alkalinity - on another);
2) division of rocks of normal alkalinity into tholeitic and calc-alkaline rocks, and rocks of elevated alkalinity – into subalkaline and alkaline;
3) division of all selected rock sets according to K2O/Na2O ratio.
For discriminating the defined series, a special software has been developed in the IGEM RAS. It is based on the accepted principles of classification and nomenclature of igneous rocks (Classification …, 1981). The following criteria of division of magmatic series were accepted:
1) the division of tholeitic and calc-alkaline series from subalkaline and alkaline is executed on the  (K2O+Na2O)-SiO2 plot with the use of equations: K2O+Na2O=0,3694SiO2 - 14,3917 (at SiO2 < 67 %) and K2O+Na2O=7,9205 (at SiO2 > 67 %) (this border is close to McDonald-Kuno criterion);
2) division of tholeitic and calc-alkaline series is conducted on FeO*/MgO-SiO2 plot with the use of equation FeO*/MgO = 0,1562SiO2 - 6,685 (A. Miyashiro's criterion);
3) division of subalkaline and alkaline series is carried out by absence (for the former) or by presence (for the latter) of modal feldspathoids (nepheline, leucite, etc.), And also on other parameters of increased alkalinity (Classification …, 1981). In areas of the studied compositions this border passes approximately on 7-10 % of normative feldspathoid.
The fields of sodic (Na), potassic-sodic (K-Na) and potassic series on K2O/Na2O-SiO2)  plot were defined. Quite reliable is such division for the basic and intermediate rocks. For felsic rocks, starting from composition of 64 % SiO2, it is less reliable. The position of rock series of different alkalinity on K2O/Na2O-SiO2 plot is the following:
K2O/Na2O < 0,25 - sodic series;
K2O/Na2O <  1 (for basic and intermediate compositions);
K2O/Na2O < 2,5 (for felsic compositions) - potassic-sodic subalkaline series;
K2O/Na2O > 1 (for basic and intermediate compositions) and
K2O/Na2O > 2,5 (for felsic compositions) - potassic series.
Besides the listed series, in the sodic series it is necessary to define a smaller subseries of mid-oceanic ridges (Na-MORB). The line which is passing through value of K2O/Na2O = 0,1 on the K2O/Na2O-SiO2 plot, reliably enough divides the fields of compositions of  tholeitic basalts of MORB and island arcs. It is extremely important in development of criteria for indicator magmatism.
The following petrochemical series have been defined: sodic tholeitic; sodic of mid-oceanic ridges and potassic-sodic tholeitic; sodic and potassic-sodic calc-alkaline; potassic-sodic and potassic subalkaline, potassic-sodic and potassic-alkaline.
Thus, the concept of “petrochemical series” is assemblage of magmatic rocks whose compositions occupy quite certain position in classification petrochemical plots, characterizing this or that type of geodynamic environments.

The relationships of petrochemical and petrogenetic series are insufficiently developed in even greater degree than those of abstract and particular formations.

         The most important features of petrochemical series are as follow:
1.          Tholeitic (ТNa, Na-MORB, K-Na) series include basalts, andesibasalts, andesites (islandites) and small volumes of dacites and rhyolites. SiO2 content in most cases is within the limits of 48-63 % (modal average SiO2 content is 53 %). Augite and pigeonite are present in the groundmass. The trend of iron enrichment is typical.
2.          Calc-alkaline (I-Na, K-Na) series includes great volumes of andesites, dacites and rhyolites at the subordinated role of basalts and andesibasalts. SiO2 content varies from 52 to 70 % (average modal SiO2 content is 59 %). The groundmass contains orthopyroxene, but pigeonite is absent. There is no trend of iron enrichment.
3.          Subalkaline potassic-sodic (SK-Na) series unites subalkaline olivine basalts, hawaiites, mugearites, trachytes, trachyandesites, trachydacites and trachyrhyolites. With the rise of SiO2 content, a regular iron enrichment of rocks is registered. The similar tendency is found for clinopyroxenes in a series: basic - intermediate - felsic rocks.
Subalkaline potassic (SК) series whose petrographic equivalent are shoshonitic series, are formed by rocks from absarokites and shoshonites to latites and potassic rhyolites. All of them, as well as rocks of a calc-alkaline series, are characterized by absence of iron enrichment trend for both clinopyroxenes and bulk rocks. Shoshonites, latites, trachytes and other related rocks make only small share (2,5 %) of all volcanic rocks known on the Earth. The petrographic content of shoshonite series has been reconsidered and considerably expanded during last years. Basic rocks make ~ 50 %, intermediate rocks - 40 %, and dacites - only 10 % of total volume of rocks. In basalts of shoshonite series the prevailing assemblage of phenocrysts comprise olivine + Augite + magnetite with more rare plagioclase, amphibole, biotite and oprthopyroxene, sometimes sanidine. In rocks of shoshonite series were found out such minerals as hauyne, sodalite and leucite, but in our classification such rocks are already included into alkaline series. It is considered (Jakes, White, 1972), that shoshonitesые series are observed mainly in mobile areas with the basement age usually more ancient than Mesozoic (Japan, the Andes, New Guinea, etc.).
1.          Alkaline (AK-Na, K) series, containing feldspathoids (nepheline, leucite), and also alkaline dark-colored minerals, etc., differ from subalkaline series by higher alkalis content and on the average lower SiO2 contents (44-47 % are usual). Rocks of alkaline series are very diverse (Magmatic rocks …, 1984).

So, the magmatic formation and magmatic series are understood as quite certain assemblages of magmatic rocks having concrete geological, petrographic and petro - geochemical sense. When for whatever reasons it is impossible to define magmatic formations or series, it is necessary to use "assemblage" of rocks notion which is understood as any assemblage of magmatic rocks, closely integrated in space, but not obligatory in time, i.e. the "assemblage" concept is the term of free usage.