Volcanic ash is a useful tool for investigation of the history of volcanic eruptions as it can be found far from
eruptive centers, and is preserved for a long time after initial deposition and has a constant mineral composition.
Imperfection of most methodical investigations of volcanic ashes is their texture sensibility. This factor make difficult
to identify volcanic ashes from the same volcano. Some magnetic properties, saturation magnetization, saturation magnetization field, and Curie Point (Tc) of magnetic minerals, however, are not sensitive to texture, but they are sensitive to magnetic-mineral composition. A more sensitive method for determining the Tc- point is the analysis of the temperature dependence of magnetic susceptibility or of inductive magnetization. The presence of peaks on the curve near the Tc-point for the monomineralic fractions (Hopkinson’s peak) helps to more carefully define individual Tc on the curve for natural mixtures of the different magnetic minerals.

This book is the first work that provides the ultimate data about chemical composition of the Kamchatka Quaternary andesites. Besides the book provides data about a phase analysis of andesites, geochemical composition, REE composition and isotopic analysis of strontium, neodymium and oxygen. The analyses are prominent for their stratification and accurate geological positioning. This allows understanding how the geological events alternated. The paper is focused on the petrogenetic peculiarities of tholeiitic (the 1st type of mantle genesis) and calc-alkali (the 2nd type of mantle-crust genesis) andesites. The book stresses that petrochemical, petrological and isotopic-geochemical correlators play a great role in distinguishing of those two types of andesites. On the basis of petrochemical database we distinguished three trends of the volcanites differentiation: stable, unstable and intermediate. These trends are supposed to be used for the determination of the volcanic activity character and types of the volcanic eruptions.
This book will be helpful as a reference guide to volcanologists, petrographers, geochemists and geologists, to those who study the genesis of volcanic rocks.

Isotope-geochemical material for Pliocene-Quaternary volcanoes of the Kamchatka region is generalized on a cartographic basis. The Sr-isotope anomalies of moderate and elevated radiogenicity, geochemically confirmed, are spatially conjugated. This made it possible to interpret these anomalies not only as a reflection of mantle plume material in the composition of volcanic rocks, but also of its hybrid environment, as a consequence of plum-lithosphere remobilization. The presence of multi-directional geochemical trends made it possible to propose the concept of moving boundary values for the composition of indicator rocks of the intraplate type and adakites, which significantly expanded the possibilities of their diagnostics. The isotope-geochemical heterogeneity of basaltoids of the region is generally determined by the peculiarities of concentration of rocks with intraplate and adakite geochemical characteristics, which allows considering the asthenospheric diapirism as the main factor of petrogenesis of Pliocene-Quaternary volcanism in Kamchatka.