PREFACE

The goal of generations of igneous geochemists is to use mineralogical and chemical laws in an attempt to explain the geological processes they are investigating. This scientific approach is both simple and rigorous. Initially it consists of highlighting magmatic differentiation trends and determining the possible underlying petrogenetic mechanism(s). Then, the major elements are used to establish the nature and the modal composition of the fractionating mineral assemblage responsible for the differentiation trends; its temporal evolution is also addressed. Finally all these data are fed into models calculating the behaviour of trace elements (and possibly isotopes), in order to account for the chemistry of the investigated igneous rocks and evolution of the parental magma. Such methodology is very powerful; not only because it is consistent with field geological data but also it is based on several independent methods. Indeed, major elements, trace elements and isotopes are governed by different principles. Thus any model predicting the coherent behaviour of these three independent parts of the dataset would possess a high internal consistency, making the modelled scenario robust.