Fremrinámur

Volcano in Iceland

Fremrinámur

Highest pointElevation939 m (3,081 ft)^[1]ListingList of volcanoes in IcelandCoordinates calderas, central volcanoes and fissure swarms, subglacial terrain above 1,100 m (3,600 ft), and seismically active areas. Clicking on the image enlarges to full window and enables mouse-over with more detail.

Fremrinámur (Icelandic pronunciation: [ˈfrɛmrɪˌnauːmʏr̥] ^ⓘ) is a volcano with a volcanic system located on the basalt plateau in Iceland. It is at the junction of the Mid-Atlantic Ridge and the Greenland–Iceland–Faeroe Ridge.^[2] It is one of five volcanic systems found in the axial rift zone in north-east Iceland.^[3] Its height is about 939 m (3,081 ft).^[1]

Geology

There is a central volcano and a fissure swarm which is part of the Northern Volcanic Zone. The Fremrinámar volcanic system is about 130 km (81 mi) long, extending to the north sea coast, and up to 12 km (7.5 mi) wide.^[4] The last eruption was in 800 BC (± 300 years).^[1] However compositional analysis of at least one recent southern local lava shows similarities to lavas from the Bárðarbunga volcanic system and so eruption history local to the volcano requires further understanding.^[5] After the last ice age there have been two periods of local activity, with a large lava shield of more than 5 km³ (1.2 cu mi) volume in the early Holocene and at least three lava shields deposited between 5000 to 3000 years ago, including the 4 km³ (0.96 cu mi) Ketildyngja lava shield.^[4] The largest recent fissure eruption was 3200 years ago and produced the Búrfellshraun lava flow which is 75 km² (29 sq mi) in area.^[4] Recent lavas have been tholeiite basalt but in the Pleistocene the central volcano erupted silicic lava and multiple tuyas and tindars were formed under the ice sheet.^[4] Associated with the central volcano is a geothermal field that is just above the top of the shield volcano deposits.^[4]

Tectonically the system forms an eastern limit to the faulting of the Tjörnes Fracture Zone. Other extensional faults in the northern 60 km (37 mi) have had seismic activity consistent with propagation of dykes without eruption in the Holocene.^[4]

References

^ ^a ^b ^c "List of Icelandic Volcanoes". Archived from the original on October 9, 2011. Retrieved June 7, 2012.
^ "Geology". Archived from the original on May 1, 2012. Retrieved June 7, 2012.
^ "Geothermal Projects in NE Iceland at Krafla, Bjarnarflag, Gjástykki and Theistareykir" (PDF). p. 13. Retrieved 12 May 2024.
^ ^a ^b ^c ^d ^e ^f Sæmundsson, Kristján (2019). "Fremrinámar Alternative name: Fremrinámur". Retrieved 14 April 2024.
^ Svavarsdóttir, S.I. (2017). Geochemistry and petrology of Holocene lavas in Bárðardalur region and their association with the Bárðarbunga volcanic system (Masters dissertation) (PDF) (Thesis). Faculty of Earth Sciences, University of Iceland. pp. 1–30. Retrieved 10 April 2024.^{: 48–9, 61–62}