Iceland Within the Northern Atlantic, Volume 2. Группа авторов
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Название: Iceland Within the Northern Atlantic, Volume 2
Автор: Группа авторов
Издательство: John Wiley & Sons Limited
Жанр: География
isbn: 9781119850878
isbn:
These glaciers have profoundly carved the island since the Neogene, with deep glacial valleys, ice-smoothed or striated rocks, countless drumlins and large areas of abandoned glacial sediments on the central plateau, especially around the Kerlingarfjöll (Figure I.21). Some volcanoes have typically subglacial morphologies, such as tabular volcanoes or tuyas, the best known of which is Herðubreið (Figure I.22). Others form alignments of ridges, the tindar, which formed at the margin of the melting caps (Figure I.23).
The waters from these glaciers have also shaped canyons with huge waterfalls, on powerful, gray and loaded water rivers, the jökullsá (Figures I.23 and I.24). These waters are currently collected for an important hydroelectric production with mainly industrial purposes (aluminum and rare metals extracted from imported ores). This resource accounts for 72% of Iceland’s electricity production.
Various cap outlets are currently being developed and managed, with water stored in very large dams, generally superimposed on the same course and designed to resist jökulhlaups of interglacial rank. Global warming in recent decades and potentially induced volcanism are likely to call this policy into question.
Figure I.21. (A) The Kerlingarfjöll surrounded by its glacial desert. (B) Perched upper cirque and (C) ice-smoothed rocks of the eastern fjords (Mjóifjörður, south of Seiðifjörður) (Brigitte Van Vliet-Lanoë©)
Figure I.22. A subglacial tabular volcano: the Herðubreið, north of Vatnajökull, North Volcanic Zone (Brigitte Van Vliet-Lanoë©)
Figure I.23. Jökulsá á Kreppa north of Vatnajökull with hyaloclastite or tindar ridges (Brigitte Van Vliet-Lanoë©)
Figure I.24. A key Icelandic resource: water. (A) Bruarjökull outlet (the glacier is at the bottom of the photograph) (LMIs©). (B) One of the Dettifoss waterfalls (Jökulsá á Fjöllum). (C) The Haslsón dam on the Jökulsá á Brú. (D) The Fannahlið aluminum plant (Hvalfjörður) (photos B, C and D: Brigitte Van Vliet-Lanoë©)
On land, Iceland’s only important and renewable resources are its water and, as a result, its hydroelectricity, as well as its many geothermal sites related to the presence of the hot spot.
In this two-volume book, we will present the geological and glacial history of this island, its current tectonic and volcanic activity and the impact of its formation on the climatic evolution of the last few millions of years. Volume 1 replaces Iceland within the geological framework of the North Atlantic, and describes its tectonic and geodynamic evolution. This second volume is dedicated to the study of the interactions between Icelandic volcanism and external geodynamics, i.e. with glaciations and the climatic evolution of the Atlantic zone during the Neogene and the Quaternary.
For color versions of the figures in this Introduction see, www.iste.co.uk/vanvliet/iceland1.zip.
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