Fremrinámur () is a

volcano A volcano is commonly defined as a vent or fissure in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most oft ...

with a located on the basalt plateau in

Iceland Iceland is a Nordic countries, Nordic island country between the Atlantic Ocean, North Atlantic and Arctic Oceans, on the Mid-Atlantic Ridge between North America and Europe. It is culturally and politically linked with Europe and is the regi ...

. It is at the junction of the

Mid-Atlantic Ridge The Mid-Atlantic Ridge is a mid-ocean ridge (a Divergent boundary, divergent or constructive Plate tectonics, plate boundary) located along the floor of the Atlantic Ocean, and part of the List of longest mountain chains on Earth, longest mountai ...

and the Greenland–Iceland–Faeroe Ridge. It is one of five volcanic systems found in the axial rift zone in north-east Iceland. Its height is about .

Geology

There is a

central volcano A central volcano is a type of volcano formed by basalts and silica-rich volcanic rocks. They contain very few or no volcanic rocks of intermediate composition, such that they are chemically bimodal volcanism, bimodal. Large silicic eruptions at c ...

and a fissure swarm which is part of the

Northern Volcanic Zone The Andean Volcanic Belt is a major volcanic belt along the Andean cordillera in Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru. It is formed as a result of subduction of the Nazca plate and Antarctic plate underneath the South America ...

. The Fremrinámar volcanic system is about long, extending to the north sea coast, and up to wide. The last eruption was in 800 BC (± 300 years). 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. After the last ice age there have been two periods of local activity, with a large lava shield of more than volume in the early

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

and at least three lava shields deposited between 5000 and 3000 years ago, including the Ketildyngja lava shield. The largest recent fissure eruption was 3200 years ago and produced the Búrfellshraun lava flow which is in area. Recent lavas have been tholeiite basalt but in the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

the central volcano erupted silicic lava and multiple

tuya A tuya is a flat-topped, steep-sided volcano formed when lava erupts through a thick glacier or ice sheet. They are rare worldwide, being confined to regions which were covered by glaciers and had active volcanism during the same period. As lava ...

s and tindars were formed under the ice sheet. Associated with the central volcano is a geothermal field that is just above the top of the shield volcano deposits. Tectonically the system forms an eastern limit to the faulting of the Tjörnes fracture zone. Other extensional faults in the northern have had seismic activity consistent with propagation of dykes without eruption in the Holocene.

References

External links

* {{DEFAULTSORT:Fremrinamur Volcanoes of Iceland Volcanic systems of Iceland North Volcanic Zone of Iceland

Geology

See also

References

External links