Álftafjörður volcano
| Álftafjörður volcano | ||
|---|---|---|
 View to the northeast towards Þvóttáskriður |
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| location | Eastern Iceland | |
| Coordinates | 64 ° 41 ′ 45 ″ N , 14 ° 25 ′ 24 ″ W | |
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| Type | Central volcano (extinct) | |
| rock | Rhyolite | |
| Age of the rock | approx. 7 million years | |
| particularities | heavily eroded slopes | |
 Mælifell with the erosion slopes Þvóttáskriður on the right, view towards Hvalnesskriður |
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The Álftafjörður volcano is a large central extinct volcano in Iceland . It is located in the southeast of the island in the interior of the Álftafjörður fjord .
The volcano was active about 7 million years ago. Today only remains of him can be seen.
Volcanic activity in Iceland's East Fjords
In the east fjords one sees again and again vertical mountain passages and lava channels, which indicates the presence and the proximity of central volcanoes. Since the east fjords have not been volcanically active for about 5 million years, it is the eroded remains of such volcanoes. The volcanically active zone has since moved west.
In the vicinity of the central volcano one sees frequent occurrences of such mountain passages, so-called gang swarms . This can be observed particularly well in the east of Iceland, because the glaciers of the Ice Age scraped in these areas for a very long time and because of the proximity of Vatnajökull they rested particularly hard on the land. They were able to expose the interior of several central volcanoes.
These central volcanoes of the East Fjords mostly looked similar to the Krafla central volcano, which is active today, with its large caldera and duct systems that extend for many kilometers, mainly to the northeast and southwest. These vertical mountain passages occur by the hundreds near the central volcano and have further horizontal and vertical branches starting from a magma chamber .
View inside the Álftafjörður volcano
On the Hringvegur you cross the interior of the old central volcano by the fjord Álftafjörður, at Hamarsfjörður the path is a little north of it. The caldera of the Álftafjörður volcano is now filled with sea water.
Vottáskríður erosional slopes on Mælifell mountain
The Mælifell mountain , where the ring road winds around an erosion slope (isl. Skriður ) at a considerable height , is part of the central volcano. The mountain Rauðaskriður at Hamarsfjörður, on the other hand, is an intrusion from the fissure system of the volcano.
The erosion slopes on Mælifell are called Þvottáskriður and in earlier times were a real obstacle to traffic because of the danger of falling rocks . Especially since the Hvalnesskriður join the Krossanesfjall directly to the west , but they belong to another eroded central volcano, that of Lón . Even today, the erosion slopes are not entirely harmless, especially in winter. That is why there are plans to build tunnels here.
Reasons for erosion
The slopes here are mainly due to sea and frost erosion . When the volcano extends into the sea, like here, the waves attack the rock and grind it up over time. However, it was the case that after the Ice Age the land rose after a certain time because the glacier load had fallen from it. Since then, it has been more the frost, with the alternating periods of thaw and frost, which is typical for south Iceland, the contraction and expansion of water that has penetrated into the many crevices, which literally breaks up the rock. This can also be seen in many other places in Iceland, such as Hafnarfjall in the west of the country.
literature
- Íslandshandbókin. Náttúra, saga og sérkenni. 2. bindi. Örn and Örlygur, Reykjavík 1989.
- Ari Trausti Guðmundsson : Á ferð um hringveginn. Líf og saga, Reykjavík 1990.
