Hrafnabjörg
| Hrafnabjörg | ||
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 Hrafnabjörg from Þingvellir |
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| height | 763 m | |
| location | Iceland | |
| Coordinates | 64 ° 16 ′ 21 ″ N , 20 ° 55 ′ 18 ″ W | |
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| Type | Tabular volcano | |
| Last eruption | around 7000 BC Chr. (Active) | |
 Mountains Skjaldbreiður (center) and Ármannsfell (left) belonging to the Hrafnabjörg system |
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The Hrafnabjörg volcano is located in Iceland . It is located in the southwest of the island, northeast of Lake Þingvallavatn .
Geology and series of eruptions
Hrafnabjörg is a 763 meter high table volcano from the Ice Age . Its volume is given by Eason et al. (2015) estimated at 1.5 km 3 .
At the same time, it may be the central volcano of its own volcanic system.
This includes the Ármannsfell tabular volcano on the other side of the Þingvellir trench .
Numerous eruptions occurred in this system immediately after the end of the Ice Age. Some of these are eruptions along volcanic crevices east of the central volcano. The pahoehoe lavas they produce fill large parts of the Þingvellir trench and can be seen well in the Almannagjá gorge . The lavas have a thickness of around 30 km³ and one can assume that they have formed over decades of eruption series.
The youngest lava from the Hrafnabjörg system is about 5,000 to 6,000 years old and is called Þjófahraun . The lava field extends from Mount Arnarfell to Lake Þingvallavatn .
Skjaldbreiður shield volcano
The shield volcano Skjaldbreiður , which is part of the system, was formed around 9000 years ago .
Influence on the lake Þingvallavatn
A series of eruptions from the Eldborgir crater series at around the same time produced lava, which decisively changed the character of Lake Þingvallavatn , both in terms of its dimensions and its flora and fauna. It blocked the direct flow of water through glacial rivers from the north and reduced the surface of the lake by 50 percent. Since then, the water from the Langjökull glacier has still been flowing into the lake, but is filtered through the porous lava and enriched with minerals, which in turn cause the lake's special flora and fauna. In addition, due to the slow constant influx and the location at the bottom of the moat, the lake slowly reached its present size.
Hike to the Hrafnabjörg
A relatively easy hike leads to the summit plateau of Table Mountain. You drive from the (old) connecting road Gjábakkavegur (the road between Laugarvatn and Þingvellir) on a jeep track in a northeast direction to Steinmann Bragabot . From there you can climb up or take a circular route through the lavas, past the Þjófahnúkur palagonite mountain .
See also
Web links
- http://notendur.hi.is/oi/geology_of_thingvellir.htm Geology of the Þingvellir area (English)
Individual evidence
- ^ Eason et al .: Effects of deglaciation on the petrology and eruptive history of the Western Volcanic Zone, Iceland. Bulletin of Volcanology, June 2015, p. 6
- ↑ Thor Thordarson, Armann Hoskuldson: Iceland. - Classic Geology of Europe 3. Harpenden 2002, p. 75
- ↑ ibid. P. 76
- ↑ ibid., P. 76
- ^ Ari Trausti Guðmundsson, Pétur Þorsteinsson: Íslensk fjöll. Gönguleiðir á 151 tind. Reykjavík 2004, p. 116 f.