Njörður

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Coordinates: 62 ° 8 ′  N , 25 ° 0 ′  W

Eruption of an undersea volcano
Research ship R / V Knorr

Njörður is an undersea volcano on the southwest coast of Iceland .

location

The volcano lies about 150 km from the mainland on the ocean floor, immediately east of the Reykjanes Ridge , an undersea ridge that is part of the Mid-Atlantic Ridge . It extends the continental shelf on which Iceland lies.

Njörður was discovered in 2007 by scientists from the University of Iceland and the University of Hawaii . This happened on the occasion of a diving boat excursion from the research vessel R / V Knorr.

shape

It is a large central volcano with an extensive caldera .

The foot of the mountain is 900 to 1200 m below the surface of the water, it rises approx. 500–800 m above the surroundings and extends up to 400 m below the surface of the water. In cross-section it measures approx. 50 km at its foot. It is crowned by two calderas, including one with the dimensions 10 × 13 km, which suggests its own rather large magma chambers .

The age of the caldera is estimated to be at least 120,000 years. It is cut by a deep ditch. On closer inspection, numerous crevices were also discovered.

meaning

The discovery of such a large central volcano at this point surprised the geologists. Since two plates move apart along the Mid-Atlantic Ridge, no such large submarine volcanic buildings have been discovered or even suspected so far. The geologists planned another excursion for 2008, but this has not yet been carried out.

The central volcano Njörður probably originates from the time when the spreading zone reached south over the Faxaflói Bay about 2.2 million years ago .

The volcano is active but does not pose a threat to Iceland's coastal residents because it is so deeply underwater.

See also

Web links

Individual evidence

  1. ↑ Ármann Höskuldsson, Richard Hey, Ferdinando Martinez, Ásdís Benediktsdóttir: Njörður central volcano, first direct evidence of shallow magma chambers on the Reykjanes ridge. (No longer available online.) January 2010, pp. 79-80 , archived from the original on November 15, 2012 ; Retrieved on March 23, 2011 (English, The volcano was the subject of several conference contributions at the “29th Nordic Geological Winter Meeting” in Oslo, January 11-13, 2010): “Njörður central volcano, is situated at the foot of the Icelandic shelf on the Reykjanes ridge with its center at 62.8 ° N and 25 ° V. Graben structures are not observed between 59 ° N and Njörður (62.8 ° N), as the Reykjanes ridge forms a topographic high along this part of the plate boundary. " Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.geologi.no
  2. ↑ a b c d Rekbeltastökk og Njörður, megineldstöð á Reykjaneshrygg. Vorráðstefna Jarðfræðafélags Íslands. (PDF, p. 13.)
  3. ^ A b Richard A. Lovett: Giant Undersea Volcano Found Off Iceland In: National Geographic News of April 22, 2008, i. A. According to the Icelandic geologist Ármann Höskuldsson (English, discovery of the Njörður)