Skjaldbreiður
| Skjaldbreiður | ||
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 Skjaldbreiður, taken from Þingvellir |
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| height | 1060 m | |
| location | Iceland | |
| Coordinates | 64 ° 24 '30 " N , 20 ° 45' 0" W | |
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| Type | Shield volcano | |
| Last eruption | around 7,000 BC | |
 Skjaldbreiður from the driveway to Uxarhryggur |
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The Skjaldbreiður ( isl . Broad shield ) is a shield volcano in southwest Iceland . It is located in the municipality of Bláskógabyggð . It was formed in an eruption about 9,000 years ago. The volcano is 1060 m high, its crater has a diameter of about 300 m. Its base diameter is around 15 km.
Hrafnabjörg
According to Thor Thordarson, Skjaldbreiður belongs to the volcanic system of Hrafnabjörg (German raven rock ). This central volcano is located a little southwest of Skjaldbreiður in the direction of Þingvallavatn . However, Skjaldbreiður assigns other literature to the volcanic system of Prestahnúkur .
Shield volcanic eruptions after the Ice Age
The Ice Age ended in Iceland about 10,000 years ago and immediately afterwards numerous shield volcanic eruptions can be detected, a phase of geological changes that Skjaldbreiður owes its origin to.
The reason was the rapid ascent of the country, which was freed from the burden of the glaciers. Changes in the pressure and location of magma reservoirs can trigger such eruptions. At the same time, the ice had closed crevices that could now open.
Shield volcanic eruptions can also be detected in Iceland in the interglacial periods.
These are predominantly effusive outbreaks , such as those seen at the beginning of the 21st century. B. can watch in Hawaii . Typically, with such eruptions over a longer period of years, from decades to centuries, very hot and thin-flowing lavas are always emitted through the same crater, so that the relatively flat volcano builds up layer by layer.
Another shield volcano on Þingvallavatn is about Lyngdalsheiði .
Þingvallavatn
The lava fields that formed when the Hrafnabjörg erupted today partially fill the basin in which the largest Icelandic lake, the Þingvallavatn , is located. The former Thingstätte Althing is also located in the lava fields in the Almannagjá gorge . Large parts of the area are occupied by the Þingvellir National Park.
Rift zone
Due to its location directly above the geologically highly active center of the Mid-Atlantic Ridge , the lava fields of Skjaldbreiður have been torn apart and deformed over the centuries. Today there is a bizarre landscape with a multitude of crevices and cracks.
Since two tectonic plates, the Eurasian on the one hand and the North American on the other, move away from each other here, the area is still subject to constant deformations, e.g. B. subjected to earthquakes. It is surrounded by four active volcanic systems (besides the one mentioned, Hengill , Prestahnúkur and Hrómundartindur ).
See also
Web links
- Skjaldbreiður in the Global Volcanism Program of the Smithsonian Institution (English)
- Geology of the area of Thingvellir (English)
- Hiking at Skjaldbreiður (PDF, Icelandic; 15 kB)
Individual evidence
- ↑ Thor Thordarsson, Armann Hoskuldsson: Iceland. Classic Geology in Europe 3. Harpenden 2002, p. 75
- ↑ Skjaldbreiður in the Global Volcanism Program of the Smithsonian Institution , accessed on October 29, 2010