E. J. Cobbing, 1999. "The Coastal Batholith and other aspects of Andean magmatism in Peru", Understanding Granites: Integrating New and Classical Techniques, Antonio Castro, Carlos Fernández, Jean Louis Vigneresse
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The opening of the South Atlantic ocean at 110 Ma triggered the inversion of the Casma basin and the switch from marine volcanicity to plutonism, which evolved through three distinct phases. The first was the intrusion of the Coastal Batholith which forms a well-defined linear structure over the whole coastal region and which, in the Lima segment, endured from 100 to 60 Ma, and was terminated by the formation of the ring complexes. The second was the post Incaic development of the andesitic terrestrial plateau volcanics, the Calipuy group with associated scattered plutons of tonalite and granodiorite, which extended from perhaps 50 Ma to 20 Ma, and the third was the emplacement of the high level stocks and associated ignimbrite sheets from 20 to 6 Ma. Of these the Cordillera Blanca batholith which is of trondhjemitic affinity is the most important, and it is the intrusives of this zone which are the most important economically. Many plutons within the Batholith were emplaced into the brittle crust by processes of magmatic stoping and some of the evidence for this process is presented.
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Understanding Granites: Integrating New and Classical Techniques
Granite magmatism represents a major contribution to crustal growth and recycling and, consequently, is one of the most important mechanisms to have contributed to the geochemical differentiation of the Earth’s crust since Archaean time. Granites are also often associated with ore bodies, and their study therefore has direct commercial relevance.
The modern view of the granite problems requires the application of many different theoretical, experimental and empirical resources provided by geophysics, geochemistry, experimental petrology, structural geology, scale modelling and field geology. Because of the complexity of the granite problem, it is necessary to integrate a variety of techniques and corroborate the findings with field observations.This is the philosophy of this book.
Many chapters are review papers dealing with the development and achievements of a particular technique, whilst other chapters deal with the application of a number of techniques to a specific problem. This volume brings together papers that would otherwise be dispersed in different publications.
The book will be of interest to igneous petrologists, geophysicists, structural geologists and geochemists.