Iceland Within the Northern Atlantic, Volume 2

1 Cover

2 Title Page SCIENCES Geoscience , Field Director – Yves Lagabrielle Lithosphere-Asthenosphere Interactions , Subject Head – René Maury

3 Copyright First published 2021 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc. Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address: ISTE Ltd 27-37 St George’s Road London SW19 4EU UK www.iste.co.uk John Wiley & Sons, Inc. 111 River Street Hoboken, NJ 07030 USA www.wiley.com © ISTE Ltd 2021 The rights of Brigitte Van Vliet-Lanoë to be identified as the author of this work have been asserted by her in accordance with the Copyright, Designs and Patents Act 1988. Library of Congress Control Number: 2021934743 British Library Cataloguing-in-Publication Data A CIP record for this book is available from the British Library ISBN 978-1-78945-015-6 ERC code: PE10 Earth System Science PE10_5 Geology, tectonics, volcanology PE10_13 Physical geography PE10_18 Cryosphere, dynamics of snow and ice cover, sea ice, permafrosts and ice sheets

4 List of Abbreviations

5 Preface

6 Introduction

7 1 Young Icelandic Volcanism and its Implications 1.1. Introduction 1.2. Icelandic magma series 1.3. Central volcanoes and active fissural systems 1.4. Volcanic hazards in Iceland 1.5. References

8 2 Volcanism and Glaciations: Forcings and Chronometers 2.1. Subglacial volcanic landforms 2.2. Volcanism, deglaciation and climate 2.3. The hypothesis of a link between volcanism and climate and its test by dating 2.4. References

9 3 Cenozoic Evolution of Iceland and the Cryosphere 3.1. Ice ages and the opening of the Atlantic 3.2. Iceland’s Quaternary glaciations 3.3. The last glacial episode and its deglaciation 3.4. Iceland today, its climate and vegetation 3.5. References

10 Conclusion

11 References

12 List of Authors

13 Index

14 Summary of Volume 1

15 End User License Agreement

1 Introduction Figure I.1. Iceland from Space (document Geographical Institute of Iceland/Landm... Figure I.2. (A) Icelandic stamp illustrating the discovery of Iceland by Irish m... Figure I.3. Traditional sheepfolds in southern Iceland with the volcano Hekla in... Figure I.4. (A) The Þingvellir graben, seen from an airplane (Þingvellir Nationa... Figure I.5. (A) The Hekla volcano (Brigitte Van Vliet-Lanoë©) and (B) its cartog... Figure I.6. Typical landscape of ancient basalts on the eastern coast of Iceland... Figure I.7. The eruption of the Eyjafjallajökull in 2010: its jökulhlaup (Reykja... Figure I.8. Sheep disturbed by the ash from the eruption (Flickr©) Figure I.9. Digital terrain model of Vatnajökull (black line: current cap bounda... Figure I.10. (A and B) Views of the Bárðarbunga caldera obliterated by ice durin... Figure I.11. Rim of the northern caldera of Grìmsvötn (Ragnar Sigurdsson©) Figure I.12. The Grìmsvötn volcano. (A) Initiation of the northward flow associa... Figure I.13. (A) The jökulhlaups of the Skafta River from the Grimsvötn in 1996 ... Figure I.14. (A) Fissural eruption of Krafla in 1980, along fractures arranged e... Figure I.15. Eruption of Krafla in 1980: hornitos on fractures and lava flows in... Figure I.16. (A) The submarine ridges of Kolbeinsey and (B) of Reykjanes (multib... Figure I.17. Trace of the Réttarnes seismic fault (1294 or 1732) in the Rangavel... Figure I.18. Destruction caused during the earthquakes of June 2000 in Bitra: (A... Figure I.19. Successive phases of an explosion of the Strokkur geyser, Geysir ge... Figure I.20. The Hofsjökull. Document made from radar images (CNES©). The calder... Figure I.21. (A) The Kerlingarfjöll surrounded by its glacial desert. (B) Perche... Figure I.22. A subglacial tabular volcano: the Herðubreið, north of Vatnajökull,... Figure I.23. Jökulsá á Kreppa north of Vatnajökull with hyaloclastite or tindar ... Figure I.24. A key Icelandic resource: water. (A) Bruarjökull outlet (the glacie...

2 Chapter 1 Figure 1.1. Distribution of recent Icelandic volcanism (modified from Þórðarson ... Figure 1.2. Icelandic magma series. Simplified diagram (modified from Jakobsson ... Figure 1.3. Evolution of major elements (% oxides) as a function of MgO in young... Figure 1.4. Sr-Nd isotopic compositions of recent Icelandic basalts and associat... Figure 1.5. The Baula rhyolitic batholith (3 My old) at the entrance to the Snæf... Figure 1.6. Geochemical comparison of tholeiitic basalts (tholeiites), alkaline ... Figure 1.7. Evolution of the average rare-earth composition of recent magnesian ... Figure 1.8. Compared isotopic compositions (Pb, Hf, Nd) of Icelandic and North A... Figure 1.9. Lead isotopic compositions of Icelandic basalts Figure 1.10. Examples of Icelandic shield volcanoes Figure 1.11. Rhyolitic volcano (on the right; diameter 250 m) with dome-like mor... Figure 1.12. Large Icelandic fissural eruptions. (A) Lakagígar fissure, 1783–178... Figure 1.13. Map of the fissural eruptions of the Eldgjá and Laki (Southeast Neo... Figure 1.14. (A) Askja S fissural eruption, 11–10.8 ky, (modified from Sigurgeir... Figure 1.15. Examples of postglacial basaltic flows. (A) Southwest of Lake Hagon... Figure 1.16. Morphology of fluid basaltic flows. (A) Ropy lava surface (“Mývatn ... Figure 1.17. Morphology and post-eruptive evolution of the Dimmuborgir lava lake... Figure 1.18. Morphology of viscous rhyolitic (obsidian) lava of aa type. Landman... Figure 1.19. Vesicles and lava flows. (A) Pipe vesicles at the base of a fluid l... Figure 1.20. Examples of lava flows Figure 1.21. Examples of pillow lavas. (A) Pillow lavas included within hyalocla... Figure 1.22. Cypressoid hydromagmatic plumes, loaded with black hydrated ashes, ... Figure 1.23. Eruptions of the Grímsvötn volcano. (A) Melting cauldron. (B) Melti... Figure 1.24. Examples of phreatomagmatic deposits. (A) Hverfjall tuff cone (Mýva... Figure 1.25. Examples of emplacement of phreatomagmatic formations Figure 1.26. The 1973 Eldfell eruption Figure 1.27. Extension of Vedde tephra in the North Atlantic (stars) and adjacen...Figure 1.28. Examples of rhyolitic deposits. (A) Subaerial pumice deposit (Hekla...Figure 1.29. Examples of tephras. (A) Spreading of fine ash from the Eyjafjallaj...Figure 1.30. Eruption of Eyjafjallajökull in April 2010. (A) Eruptive plume of t...Figure 1.31. Evolution of the lake level in the Grímsvötn caldera between 1930 a...Figure 1.32. Some effects of jökulhlaupsFigure 1.33. Examples of jökulhlaup- related erosion Figure 1.34. Examples of jökulhlaups- related sedimentary deposits Figure 1.35. Map of the extension of postglacial jökulhlaups (maximum flood infl...Figure 1.36. Traces of soil erosion (highlighted by vegetation) induced by jökul...Figure 1.37. (A) Deflation by north wind overflowing the sea, in the extension o...Figure 1.38. Main Late glacial and Early Holocene tephras in relation to jökulhl...Figure 1.39. Interstratified rhyolitic and basaltic tephras (A) in the Vopnafjör...Figure 1.40. Examples of Icelandic loess deposits and their erosion Figure 1.41. Examples of Icelandic dunes. (A) Vegetated dunes (Grímsstaðir). (B)...