Page 26 - Caldera Volcanism Analysis, Modelling and Response

CHA P T E R 1

Residence Times of Silicic Magmas

Associated with Calderas

Fidel Costa

Contents

1. Introduction 2
1.1. What is the residence time of a magma? 3
1.2. Magma production and cooling rates 4
1.3. Choice of caldera systems and organisation of the manuscript 4
2. Methods for Obtaining Time Constraints of Magmatic Processes 5
2.1. Radioactive isotopes 5
2.2. Chemical diffusion, relaxation of mineral zoning 9
2.3. Other methods of obtaining time scales of magmas related to calderas 10
3. Residence Times of Magmas Associated with Selected Calderas 11
3.1. Taupo volcanic zone 11
3.2. Toba Caldera complex 16
3.3. Yellowstone calderas 18
3.4. Long Valley system 22
3.5. Valles-Toledo complex 30
3.6. La Garita caldera 32
3.7. Other calderas 34
4. Interpretation of Residence Times and Integration with Thermal and
Mechanical Constrains 35
4.1. What do the residence times indicate? 35
4.2. Time scales of magmatic processes 41
4.3. Magma production and cooling rates related to calderas 42
4.4. Magma residence times, caldera collapse and the rheology of the crust 45
5. Summary and Conclusions 45
Acknowledgments 47
References 47

Corresponding author. Tel.: ++34-93-4095410; Fax: ++34-93-4110012
E-mail address: fcosta@ija.csic.es
CSIC, Institut de Cie `ncies de la Terra ‘Jaume Almera’, Lluı ´s Sole ´ i Sabarı ´s s/n, 08028 Barcelona, Spain.
Developments in Volcanology, Volume 10 r 2008 Elsevier B.V.
ISSN 1871-644X, DOI 10.1016/S1871-644X(07)00001-0 All rights reserved.
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