To the Russian translation of the abridged version of the International Stratigraphic Guide

"The International Stratigraphic Guide" edited by Prof. H. Hedberg was issued in 1976. In Russian lit- erature it was often called "Code" or "Reference book" (Mezhdunarodnyi stratigraficheskii sprovaochnik,

1978). Its publication marked the termination of the first period of the post-war activity of the International

Subcommission on Stratigraphic Classification (ISSC) headed by Prof. H. Hedberg. Although the Interna- tional Commission on Stratigraphy recommended the publication of the Guide, it has not been approved as the Code because of its one-sided character and criticism of some members of the Commission (Menner,'

1977).

Nevertheless, the Guide gained a wide recognition in different, most of all, English-speaking countries and promoted more universally acceptable approach to Stratigraphic classification, nomenclature, and proce- dure. This facilitated the international communication of geologists and their mutual understanding.

The second edition ofthe Guide (ed. Prof. A. Salvador) came out after 18 years, in 1994 (International

Stratigraphic Guide, 1994). The document retained its general spirit but some important supplements and corrections were made. For instance, categories of magnetostratigraphic and unconformity-bounded units were established and essential and methodically important refinements were introduced to the interpretation of biostratigraphic units. The description of procedure for extending chronostratigraphic units (chronocorre- lation) by using different methods is of extreme significance.

The first edition ofthe Guide was translated into Russian in 1978 and widely distributed in the country

(3800 copies), whereas the second edition is as yet unknown to Russian geologists. Only few copies ofthe

Guide-1994, which has not been translated into Russian, are available.

Recently "Episodes" (1999. Vol. 22, no. 4) presented the abridged version ofthe second edition ofthe

Guide. The version was prepared by the ISSC and edited by M. Murphy and A. Salvador. The editors believe that the abridged version is more accessible (first of all, in relation to the cost) and available for stratigra- phers and for specialists and students in other branches of geology in different countries. Its advantages are the brevity and pragmatism as well as clear definition and classification of Stratigraphic units. This especially concerns the zonal categories of different types. The Guide emphasizes the significance of regional and local Stratigraphic schemes for developing the Standard Stratigraphic Scale. Lately their significance has been di- minished, probably, because ofthe enthusiasm for global correlations. We can indicate some other merits of the Guide. We welcome the publication ofthe abridged version that is of much use for geologists of different countries.

The world Stratigraphic practice began to overcome the differences between so called «European» and

«American» Stratigraphic schools, which seemed earlier insuperable. Some ofthe differences still remain and need to be discussed. Many remarks were made during the preparation ofthe second edition ofthe Guide and

its abridged version (As the member ofthe International Subcommission on Stratigraphic Classification and Nomenclature, I also took part in the discussion). Regretfully, many suggestions, including the important ones, have not been taken into account. This evidently happens with all reference books whose editors sup-

port the only one point of view. The main concept of the Guide is so called multiple stratigraphy, which con- sists of independent lithostratigraphy, allostratigraphy, biostratigraphy, magnetostratigraphy and chro- nostratigraphy. This point of view is not commonly accepted. Many stratigraphers support the concept ofthe

single stratigraphy based on the integrated employment of all methods for recognizing Stratigraphic units. The Guide places the main emphasis on chronostratigraphy that deals with the body of rock strata formed during a specific interval of geological time. However, principles of Stratigraphic subdivision of rocks, which

serve as the base for certain chronostratigraphic schemes, are not virtually described. In other words, the question what is the base of recognition of chronostratigraphic units remains unclear. The historical- geological principle of the subdivision must be specially accented. Instead, chronostratigraphic units are

6 Международный стратиграфический справочник - сокращенная версия. 2002 г.

recognized by definition of their boundaries in sections (according to the so-called concept of "golden spikes"). Thus, "stage is defined by their boundary stratotypes" and so on.

There are some other disputable points. For example, the notion of classification is not valid in relation of stratigraphic units (Suffice it to say that stages of different systems have been classified on different bases).

Definitions of stages, series, systems, erathems, and eonothems seem to be unhappy (e.g., system is defined as a subdivision of higher rank than series but lower rank than erathem). Many (although not all) stratigra- phers would object to the definition of chronozone as a subdivision of uncertain rank outside the hierarchy of

chronostratigraphic units.

In view of the objections made, the editors of the Guide propose it as a recommended approach to strati- graphic classification, terminology and procedure rather than as the Code. In the course of further interna-

tional cooperation some propositions of this document may be used to develop the universally acceptable

International Stratigraphic Code in spite of different national approaches to stratigraphic problems.

We think that the translation of the abridged version into Russian will be of much help to our specialists. The translation was made by Yu. B. Gladenkov, T. N. Golodnyuk and O. A. Korchagin of the Laboratory of

Phanerozoic Stratigraphy of the Geological Institute of the Russian Academy of Sciences and subsequently edited by Yu. B. Gladenkov and O. A. Korchagin. The text of the translation is slightly simplified but keeps

the American "style" of some definitions. It retains all structure of the original text and, what is very impor- tant, includes definitions of many terms commonly used abroad.

Certainly, the abridged version of the Guide (as well as the Guide itself) cannot substitute for the Russian

"Stratigraphic Code" of 1992, which has been successfully used for a long time in stratigraphic investiga- tions. However, the acquaintance with this version allows us, on the one hand, to estimate different strati- graphic approaches, especially to the problems of stratigraphic classification, and, on the other hand, to infer tendencies of its development.

I am very grateful to Prof. E. F. de Mulder, President of International Union of Geological Sciences, Prof. F. Gradstein, President of International Commission on Stratigraphy, and Prof. A. Salvador, author of the

International Stratigraphic Guide, who encouraged the publication of the Russian version of the abridged

Guide.

Prof. Yu. B. Gladenkov Responsible editor of the Russian version

Редакторы Майкл А. Мёрфи* и Амос Сальвадор**