This book will help geology students to understand and use geochemical tools to determine the origin and evolution of magmas, and to gain a basic understanding of geochronology (rock dating) using a number of common methods.- Chapter I covers general geochemistry and the modeling of geochemical processes such as fractional crystallization and partial melting.- Chapter II covers geochronology (absolute dating Ar -Ar; K-Ar; Rb-Sr, Sm-Nd; U-Pb on zircon) and isotope geochemistry.Calculation examples are given for the various models. This work complements the book "Abla Azzouni-Sekkal.2024. Les roches magmatiques, étude et applications pratiques, Editions universitaires européennes, 138 p.