Systematics of the Magmatic Processes.: A Practical Approach to the Study of Pet

Since the majority of the outcrops have been already discovered, the job of the field geologist becomes increasingly complicated with each passing day. We now need to re-orient our work in an effort to in-terpret the geochemical, geophysical and other signals related to these blind and/or buried mineralized rocks.
In our help come more sophisticated equipments, new powerful software and more rational geological theories, all of which demand from us a more complete theoretical formation.
On the other pan of the scale, we have graduate and post-graduate students with a solid theoretical background, but with little practical experience. The majority of their textbooks are more concern with theory then with its practical application. Examples in these books are fictitious or at best simplified. The reason is clear- we need to teach them a “necessary minimum” in the confidence that practice will teach them more latter. Thus, one can ask the following question:  Is this an unavoidable gap?
My main objective in writing this book has been to put together the theory of the magmatic processes with the practical aspect of how to study these processes. I hope it will be useful not only for the aver-age student in the task of understanding the systematic of the magmatic processes, but chiefly for any-one confronted with the problem of processing and studying petrologic data.
The text has been put together to emphasize the practical part on each chapter. Real examples are pro-cessed step-by-step and the proper macros in Microsoft Excel are given to facilitate similar analysis in the future.
I start with a description of the main characteristics of the igneous rocks, their modern nomenclature, and the main rock types on each of the four defined groups of Ultramafic, Mafic, Intermediate, and Felsic igneous rocks and their effusive analogues. I will also introduce here the Igneous Rock IdentifierTM , and explain how to use it.
Chapter 2 will be dedicated to the field study of the igneous rocks. Here I will talk about the most common textures and the sequence of field studies of the igneous rocks, and some recommendations on how to name igneous rocks in the field.
After a brief introduction to the systematic of the magmatic processes in Chapter 3, we will deal with the quality requirements of the analysis and the pre-elaboration of the data in Chapter 4.
Of a cardinal importance is Chapter 5, where you will learn how to determine the degree of incom-patibility of the trace elements, and I will introduce a model for the determination of the most probable magmatic process. The answer to this problem has not only a theoretical value, but also a very practical one, as it is discussed here.
Chapters Six to Eight are dedicated to more detailed studies of the Partial Melting, Fractional Crys-talliza¬tion, Mixing and Contamination Processes, so they maybe of more interest to researchers and students then to field geologists. However, field geologists ARE invited to test these models also.
A sequence of procedures for the petrologic evaluation of a suite of magmatic rocks is explained in Chapter 9, based on real case studies. This includes the use of geochemical data in the interpreta¬tion of tectonic events. Because of its practical approach, this chapter will be of more interest to field geolo-gists... However, students and researchers ARE invited to test them also.
There is an Old Spanish proverb: “Who embraces too much, can squeeze too little”. Clearly, I cannot hope to cover all the problems of the field study of the magmatic processes. Consequently, I have tended to focus on filling the gap between the theoretical knowledge and their practical application.
I want to thank Dr. Don Francis, Dr. Walter Trzcienski, Dr. Christopher Brooks, and Dr. John Stix, for their help and encouragement throughout the completion of this work, and also to Christopher Gam-ons, Denis Villeneuve, and many others colleges that tested these techniques and suggested many im-provements. A lot of information and figures were taken from the INTERNET community. Finally, I could not forget to mention and thank all my students. To their questions and necessities I own this book. Thank you all.
 
Ricardo Valls