Page 122 - Caldera Volcanism Analysis, Modelling and Response

CHA P T E R 3

The Use of Lithic Clast Distributions in

Pyroclastic Deposits to Understand
Pre- and Syn-Caldera Collapse Processes:

A Case Study of the Abrigo Ignimbrite,

Tenerife, Canary Islands

1, 1 2 2 2
A. Pittari , R.A.F. Cas , J.A. Wolff , H.J. Nichols , P.B. Larson and
J. Martı ´ 3

Contents

1. Introduction 98
2. Review of Lithic Component Studies and Inferred Caldera Processes 99
2.1. Lithic-rich pyroclastic deposits 99
2.2. Quantifying spatial variations in lithic assemblages 101
2.3. Lithic clast provenance 103
2.4. Hydrothermally altered lithic clasts 104
2.5. Vent configurations 105
2.6. Conduit-vent dynamics 105
3. Case Study of the Abrigo Ignimbrite 106
3.1. Geology of Tenerife 106
3.2. The Abrigo ignimbrite 108
3.3. Lithic clast types and their provenance 110
3.4. Quantitative analysis of lithic clast populations 120
3.5. Supporting evidence from juvenile clast and syenite
geochemical compositions 127
3.6. Geological configuration of the
Las Can ˜adas edifice prior to the Abrigo eruption 129
3.7. Destruction of the pre-Abrigo volcanic system 132
3.8. Implications for pyroclastic flow processes 134

Corresponding author. Tel.: +61-39905-4885, +64-7-838 4466, Ext.: 8582; Fax: +61-39905-4903; +64-7-856 0115
E-mail address: apittari@waikato.ac.nz
1
School of Geosciences, Monash University, Victoria, 3800, Australia; Department of Earth and Ocean Sciences, University of
Waikato, Private Bag 3105, Hamilton, 3216, New Zealand
2
School of Earth and Environmental Sciences, Washington State University, Pullman, Washington, 99164, U.S.A.
3
Institute of Earth Sciences ‘ Jaume Almera’, CSIC, c/Lluis Sole Sabaris s/n, 08028 Barcelona, Spain
Developments in Volcanology, Volume 10 r 2008 Elsevier B.V.
ISSN 1871-644X, DOI 10.1016/S1871-644X(07)00003-4 All rights reserved.
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