By means of world’s volcanoes eruptions database periodicity of volcanic process in separate areas of suburb of Pacific Ocean and for separately taken volcano is revealed. It has appeared that the revealed periods are close to the periods of seismic process: T1 ≈ 198±17, T2 ≈ 2T1 ≈ 376±12 and T3 ≈ 4T1 ≈ 762±17 years. "Parity" of these periods can testify to "isolation" of suburb of Pacific ocean. Existential distribution of volcanic activity within suburb of Pacific Ocean was studied. It has been shown, that volcanic eruptions with W ≥ 4 (the volume of erupted is material 0.01 км^3 and more) for last 12 thousand years tend to migrate clockwise in the direction from New Zealand to the South America with a speed about 10 km/year, confirming earlier received results.

The Klyuchevskoi group of volcanoes (KGV) in Kamchatka is the most powerful existing island arc and subduction zone volcanic center. The Holocene volcanic activity in the southern part of the KGV is concentrated in a large basaltic volcano, Ploskii Tolbachik (PT), altitude 3085 m and in itsTolbachik zone of cinder cones (TZ), length 70 km, which are similar to Hawaiian-type volcanoes and their rifts. A variety of different basalt types are erupted at a rate of 18 x 106 t/yr. This paper provides information on the PT peripheral magma chamber obtained by several independent methods. We used data on the evolution, eruptions, magma discharge, deformation, and earthquakes in the PT and TZ, as well as calculations that give the size of the PT flow-through magma chamber. The use of seis- mological and geodetic data places the chamber under the PT summit caldera, gives its transverse size as below 6 km, and the top of the chamber at a depth of 2 km. Our calculations give 4.9-5.8 km for the transverse chamber dimension, 3.2-3.9 km for its vertical dimension, 40-70 km' for chamber volume, and about 4 km for the depth of chamber center. The information we provide makes the properties of this source of PT and TZ alumina-rich basalts clear, as well as those of the entire KGV complex plumbing system.

Освещаются закономерности долговременного развития вулканического процесса, место и роль в нем вулкано-тектонического образования структур на основе широкого комплекса геологических, петрографических и микрозондовых минералогических данных. Обсуждается происхождение сложнодифференцированной серии изверженных пород с признаками толеитовых и известково-щелочных и взаимосвязь их вулканических и плутонических фаций.

Petrographic Code of Russia is a set of fundamental rules and recommendations approving and confirming the unified and standardized petrographic terminology and nomenclature of endogenic and coptogenic formations, as well as the taxonomy of petrographic units. The unified notional base, which forms the basis of the Petrographic Code, is used during compilation of the State Geological Maps at different scales, serial legends to them, during forecast-prospecting works, thematic investigations, as well as during map compilation in the framework of international projects.

The Code of the second and third editions has a new structure as compared to the first one, new appendices are prepared. Taking into account new requirements of the geological practice, new sections on sedimentary-volcanogenic formations, migmatites etc. are added. Sections related to metamorphic and metasomatic formations are reworked; distinguishing of fluid-explosive rocks bearing different mineral types into an individual genetic type is substantiated. The content of most of previous provisions is changed; many articles are reworked or abbreviated, new ones are included. Recommendations of the Commission on Systematics in Petrology of the International Union of Geological Sciences are taken into account during development of the Code.