Tindfjallajökull (, alternatively Tindafjallajökull) is a glacier in the south of Iceland whose name is also given to the underlying

stratovolcano A stratovolcano, also known as a composite volcano, is a typically conical volcano built up by many alternating layers (strata) of hardened lava and tephra. Unlike shield volcanoes, stratovolcanoes are characterized by a steep profile with ...

. Tindfjöll (, "peak mountains") is a ridge that extends to the south of the glacier and is an alternative name for the volcano. The name of the glacier in Icelandic means "Tindfjöll glacier".

Geography

Its highest peak is Ýmir at , which takes its name from the giant

Ýmir In Norse mythology, Ymir (), also called Aurgelmir, Brimir, or Bláinn, is the ancestor of all jötnar. Ymir is attested in the ''Poetic Edda'', compiled in the 13th century from earlier traditional material, in the ''Prose Edda'', writte ...

of Norse mythology. The peak Ýma is about to its east. The Thórólfsfell (Þórólfsfel) tuya at is on the southern flanks of Tindfjallajökull, about south of the glacier. Its eastern slopes abut the Þórsmörk

ignimbrite Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surrou ...

. The western flank has a prominence near Austurdalur and the eastern flank that of Vestriöxl at . About to the north of Ýma is the peak of Sindri at . Ásgrindur at is a similar distance north of Ýmir.

Volcano

The central volcano is in diameter with a wide caldera and has erupted rocks of

basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...

ic to

rhyolitic Rhyolite ( ) is the most silica-rich of volcanic rocks. It is generally glassy or fine-grained (aphanitic) in texture, but may be porphyritic, containing larger mineral crystals ( phenocrysts) in an otherwise fine-grained groundmass. The miner ...

composition. The most recent eruption is suspected to have been in the

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 the prior mountain building eruptions must have been before 55,000 years ago. There are eight tuyas in the volcanic system. The largest, the asymmetric Thórólfsfell tuya with its area of about and prominence of about is the type tuya for tuya's where there is no evidence for the presence of a large and long-lived meltwater lake under the ice cover, as meltwater was able to drain away between its formative eruptions. In the 1980's it was postulated that the Þórsmörk ignimbrite originated from the volcano but it originated from

Torfajökull Torfajökull ( Icelandic for "Torfi's glacier"; ) is a rhyolitic stratovolcano, with a large caldera (central volcano) capped by a glacier of the same name and associated with a complex of subglacial volcanoes. Torfajökull last erupted in 1477 an ...

to the north. Sultarfell is a pale coloured rhyolitic hill in the fissure swarm north-east of Tindfjallajökull. There is a hot spring in Hitagil to the south-east so some geothermal activity remains.

Glacier

It is capped by a glacier that has been mapped to a maximum in the 1890's of about in area, but which by 2019 had had a 45% decrease in area. In 1945 to 1946 it was mapped to an area of , in 2000 and 2019 . The only current outlet glacier with a moraine is unnamed down the Eystri Botná valley but between 1994 and 2006 had surge glacier characteristics before regressing again. Part of the glacier to the north has now separated into three with one glacier being called Blesárjökull. A small glacier on the eastern slopes of Ýma called Ýmujökull has disappeared. The rivers that flow from the glacier are Hvítmaga to the north-east, Gilsá to the south, Þórólfsá to the south-west, Valá to the north-west and Blesá to the north. Hvítmaga, Gilsá and Þórólfsá drain into

Markarfljót Markarfljót () is a river in the south of Iceland. It is approximately long and has had in pre-history jökulhlaups which would be potentially catastrophic, if a similar sized one was to happen in the future. Geography The Markarfljót rises ...

while Valá and Blesá drain into Eystri Rangá .

References

External links

Tindfjallajökull
in the

Catalogue of Icelandic Volcanoes The Catalogue of Icelandic Volcanoes (CIV) is a web resource that was created to serve as an official source of information about potentially active volcanoes monitored by Iceland. The creation of the website followed the disruptive 2010 eruption ...

Map of the area
{{DEFAULTSORT:Tindfjallajokull Stratovolcanoes of Iceland Southern Region (Iceland) East Volcanic Zone of Iceland Glaciers of Iceland Subglacial volcanoes of Iceland Calderas of Iceland Central volcanoes of Iceland Pleistocene stratovolcanoes Pleistocene calderas Ymir

Geography

Volcano

Glacier

See also

References

External links