Iceland

• Éditeur: Dunedin Academic Press
• Année: 2014
• ISBN:
  9781780465111
• Sujet: Ciencias físicas
• Sous-sujet: Sismología y vulcanismo

A concise and authoritative field guide to an exceptional natural laboratory, this title in the Classic Geology in Europe series is an essential companion for those visiting Iceland to observe the Earth in action. Rifting of the crust, volcanic eruptions and glacial activity are among a host of processes and features to be observed in this fascinating land. Nowhere else on Earth is the volcanic and tectonic architecture of seafloor rifts better exposed. Large icecaps and extensive river systems grind down the volcanic pile at rapid rates, dispersing and forming thick sequences of sediments. These formations are further modified by the pounding waves of the North Atlantic causing intriguing landforms that exhibit an intricate balance between the construction and erosion of land. Iceland is the only part of the North Atlantic Large Igneous Province that is still active and the only place on Earth where the construction of such provinces can be observed directly. As such, it is a window into the formation of proto-continents early in the Earths history. For the past seven million years Iceland has been situated at the boundary of major air and ocean masses and has consequently been exposed to extreme climate changes. The effects of the climate on the rock-forming processes are clearly illustrated by diverse sedimentary and volcanic successions and by the wide range of volcanic landforms formed in sub-aqueous to sub-aerial environments; each succession reflecting the characteristics of internal and external processes.Icelandic culture cannot be fully comprehended without understanding its geology. Thus the book will interest not only student, amateur and professional geologists but also others attracted by the natural environment and seeking a deeper understanding of what makes Iceland the unique place that it is.

First published in 2014 by

Dunedin Academic Press Ltd

This ebook edition published 2014

Head Office:

Hudson House

8 Albany Street

Edinburgh EH1 3QB

ISBNs:

Print edition (paperback): 9781780460215

Epub edition: 9781780465111

Kindle edition: 9781780465128

Copyright © 2014 Thor Thordarson & Ármann Höskuldsson

The right of Thor Thordarson & Ármann Höskuldsson to be identified as the authors of this work has been asserted by them in accordance with sections 77 & 78 the Copyright, Designs and Patents Act 1988.

A catalogue record for this book is available from the British Library.

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Figure 0.1 Hekla in South Iceland, the queen of icelandic volcanoes, viewed from southwest.

Last explosion of Grímsvötn eruption 2011 on 25 May at 14:00 hrs. View to west. Photo by Ármann Höskuldsson.

Figure 1.1 Iceland is an elevated plateau in the middle of the North Atlantic, situated at the junction between the Reykjanes and Kolbeinsey Ridge segments. The red dashed line shows the position of the Iceland mantle plume from 65 million years to the present day.

Figure 1.2 The principal elements of the geology in Iceland, outlining the distribution of the major geological subdivisions, including the main fault structures and volcanic zones and belts. RR, Reykjanes Ridge; RVB, Reykjanes Volcanic Belt; WVZ, West Volcanic Zone; MIB, Mid- Iceland Belt; EVZ, East Volcanic Zone; NVZ, North Volcanic Zone; TFZ, Tjörnes Fracture Zone; KR, Kolbeinsey Ridge (KR); ÖVB, Öræfi Volcanic Belt; and SVB, Snæfellsnes Volcanic Belt.

Figure 1.3 A stylized cross section showing the general structure of the Icelandic crust from the Snæfellsnes Peninsula across the West Volcanic Zone. Loading by volcanism tilts the strata towards the volcanic zones, forming a shallow syncline centred on the spreading axes and a shallow anticline in the region between the volcanic zones. The formation of volcanic zone by propagation through older crust results in formation of major unconformities as is illustrated by the inset graph on the left. The inset graph on the right shows the spreading paths for crustal elements (black rectangles) formed within different parts of an actively spreading volcanic zone. Rocks formed near the edge of the zone follow a shallow spreading path, whereas those formed close to the spreading axis follow a much steeper path. The dashed lines are planes of equal age and the dotted lines are isotherms. The...