Basalts and Phase Diagrams

The science of igneous petrology is founded on astute observation of rocks, guided by the rigorous principles of physical chemistry. It is, perhaps, the wedding of fallible observation with rigorous theory that makes this such a delicious science. In view of this, it is appropriate to study rocks and phase diagrams hand in hand. Good books on petrography abound, but there are few introductory books on phase diagrams, and none that illustrate in detail the quantitative analysis of...
More Description

The science of igneous petrology is founded on astute observation of rocks, guided by the rigorous principles of physical chemistry. It is, perhaps, the wedding of fallible observation with rigorous theory that makes this such a delicious science. In view of this, it is appropriate to study rocks and phase diagrams hand in hand. Good books on petrography abound, but there are few introductory books on phase diagrams, and none that illustrate in detail the quantitative analysis of fractional and equilibrium crystalliza­ tion and melting, the four limiting processes capable of rigorous discussion. This book is an attempt to remedy the deficiency. Basalts underlie some 70 percent of the earth' s surface and represent the most abundant magma type on both the earth and the moon. It is therefore fitting to address their origin in some detail. As it happens, most of the interesting principles of phase equilibrium diagrams as applied to igneous rocks can be illustrated with basalts. I have therefore tied the exposition of phase diagrams to the larger story, still unfolding, of the origin and fate of the basaltic magma. In so doing, one neglects many interesting rocks, but their origins can be studied using the principles developed here.