The Mexican Volcanic Belt is a complex continental-margin volcanic province that crosses central Mexico from the Pacific coast to the Gulf of Mexico coast and forms part of the Pacific Ring of Fire. Calderas and Ignimbrites of the Central Sector of the Mexican Volcanic Belt focuses on the calderas in the central portion of this belt, where calderas are more abundant and less well known than those in the eastern and western sectors of the province. Many caldera descriptions are published here for the first time. The calderas and related ignimbrites cover a wide span in time and space, with a Miocene-Pliocene age range. Very interesting magmatic and volcanic processes occur in each particular caldera and each caldera-ignimbrite description is unique. This book gives a description of these various processes and aligns them with what is known globally and provides geoscientists with a better understanding of the regional context of the calderas in the Mexican Volcanic Belt.
Describes in detail the large range in textures and compositions of ignimbrites and includes new information about calderas in Mexico
Provides a geologic map and stratigraphic type sections of the ignimbrites and associated calderas
Summarizes over 20 years of research by the most recognized expert on calderas in Mexico - his expertise on the subject is well recognized internationally
Table of Contents
1. Introduction 2. Caldera types classification 3. The Mexican Volcanic Belt 4. Regional stratigraphy and tectonics of the central sector of the MVB 5. The Amazcala caldera 6. The Amealco caldera 7. The Los Agustinos caldera 8. The Apaseo caldera 9. The Donguinyó-Huichapan caldera complex 10. The Santa María Macua caldera 11. The Los Azufres caldera 12. The La Muerta caldera 13. The San Pedro El Alto caldera 14. The Catedral caldera 15. Volcano-tectonic and geochemical implications. 16. Economic benefits
Authors
Aguirre-Diaz, Gerardo J.
Gerardo Aguirre's main scientific interests are three, 1) physical and chemical processes in volcanology, 2) origin and development of collapse calderas and related ignimbrites, and 3) relationships between volcanism/magmatism and tectonics. He has focused his research on the study of collapse calderas and associated ignimbrites, but has worked as well in other volcanic features, such as monogenetic volcanic fields, rhyolitic lava domes, and stratovolcanoes. For the past 5 years, he has been actively working on collapse calderas, not only in Mexico, but in other countries too, such as Las Cañadas at Spain, Aguascalientes and Caviahue at Argentina, and Cañas Dulces and Miravalles at Costa Rica. He is a geologist, and his main contributions include volcanic stratigraphy and geologic mapping of volcanic centers, particularly of calderas, from which he builds the geologic or volcanic evolution of them, documenting this basic geologic research with geochronologic, petrographic, and geochemical data, obtained by him or from other colleagues that collaborate with him. Therefore, he favors the idea that geologic and stratigraphic information is the basis for more elaborated studies, such as petrology and modeling; by modeling, he means petrogenesis and physical analogue experiments, and models obtained from numeric methods. For the past 28 years he has worked in the two main volcanic provinces of Mexico, the mid-Tertiary Sierra Madre Occidental and the Miocene-Quaternary Mexican Volcanic Belt. The former includes the largest continuous ignimbrite province of the World, and the origin for this large ignimbrite volume has been a matter of debate in terms of both petrogenesis and deficit of observed vents; there are quite few calderas recognized for the about 460,000 km3 of silicic ignimbrites. In 2003 and 2008 he and his colleagues propose an alternative model of fissural vents for explaining the large volume of ignimbrites and the relative lack of classic circular calderas. These vents are in turn related to grabens of the Basin and Range extensional province. Thus, he has coined the name of graben caldera for these volcano-tectonic depressions. Sierra Madre Occidental host a large number of World famous mining districts, such as Guanajuato, Bolaños and Tayoltita. In recent studies, he has found a direct link between the hydrothermal ore deposits with some graben calderas and current studies by him lead in that way. On the other hand, the Mexican Volcanic Belt includes at least 20 calderas, some of which are active and related to possible volcanic danger but also to geothermal energy, such as Los Humeros, Acoculco, Los Azufres and La Primavera. However, most of the Mexican Volcanic Belt calderas are inactive and cannot be sites for potential geothermics or volcanic danger, but are instead interesting and important to solve scientific problems regarding volcanic evolution of calderas, magma mingling, repetitive caldera collapse, flow dynamics in ignimbrite-forming eruptions, and geochemical unusual features. As a result of Gerardo's work on collapse calderas, in 2006 he co-funded and co-coordinated the Working Group on Collapse Calderas, which later, at March 2008, became the IAVCEI's Commission on Collapse Calderas, being one of the commissioners of it until November 2010. In its relative short live the Commission on Collapse Calderas has been quite dynamic and has shown important results, including the organization of workshops that have took place regularly every two years, a book on Caldera Volcanism with the state of art in this topic published in 2008 by Elsevier, and just recently, the implementation of a short course on collapse calderas, the first of which taking place at November 2010 as part of the 3rd Workshop on Collapse Calderas at La Reunion, France.
