Stóra-Eldborg undir Geitahlíð (; also Stóra-Eldborg við Geitahlíð ) is a small

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 ...

volcano 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 ...

, on

Reykjanes Reykjanes () is a small headland on the south-western end of the Reykjanes Peninsula in Iceland, giving the main peninsula its name. Volcanic action is responsible for forming the entire peninsula. The nearest town is Keflavik. The name, , trans ...

peninsula, 50 m high,Íslandshandbókin. Náttúra, saga of sérkenni. Reykjavík 1989, p. 45 with a 30 m deep

crater A crater is a landform consisting of a hole or depression (geology), depression on a planetary surface, usually caused either by an object hitting the surface, or by geological activity on the planet. A crater has classically been described ...

.Reynir Ingibjartsson: 25 Gönguleiðir á Reykjanesskaga. Náttúrann við Bæjarveggin. Reykjavík , p.112 - 117 It is located at about 5 km from

Krýsuvík Krýsuvík (also Krísuvík, both pronounced in Icelandic language, Icelandic) is an area in Southwest (Icelandic constituency), Southwest Iceland at about 35 km from Reykjavík. Geography and access It is situated on the Reykjanes penins ...

and as the name says at the foot of a bigger mountain, the

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 ...

of ''Geitahlíð''.

Volcanism

Eruption fissures of the Brennisteinsfjöll volcanic system

Despite its location, just some 5 km from the high temperature area of Seltún, the volcano and its counterparts, the crater rows, fissures, as well as the

''Geitahlíð'' (385 m) with the crater Æsubúðir on its top, are not part of the Krýsuvík volcanic system, but of the volcanic system of

Brennisteinsfjöll Brennisteinsfjöll (, "Sulfur mountains"
Brennisteinsfjöll. Detailed description. In: Catalogue of Icelandic Volcano ...

as its southernmost outpost. Eldborgir erupted about 2400 BP. The crater row also includes some

lava channel A lava channel is a stream of fluid lava contained within zones of static (i.e., solid and stationary) lava or lava levees. The initial channel may not contain levees per se, until the parental flow solidifies over what develops into the channel a ...

s. The lava extruded during the eruption ran to the sea.

The pyroclastic cones

Stóra-Eldborg undir Geitahlíð is a

pyroclastic cone Volcanic cones are among the simplest volcanic landforms. They are built by ejecta from a volcanic vent, piling up around the vent in the shape of a cone with a central crater. Volcanic cones are of different types, depending upon the nature and s ...

, built up mostly from spatter and

scoria Scoria or cinder is a pyroclastic, highly vesicular, dark-colored volcanic rock formed by ejection from a volcano as a molten blob and cooled in the air to form discrete grains called clasts.Neuendorf, K.K.E., J.P. Mehl, Jr., and J.A. Jackso ...

it forms part of a crater row. Another such eruption fissure is to be found nearby, therefore Icelanders prefer the plural ''Eldborgir undir Geitahlíð''. One of the eruption fissures dissects the older tuya Geitahlíð. The ''Litla-Eldborg'' crater is part of the parallel crater row and eruption fissure. The eruption products of both fissures are petrologically different when compared. For this reason, it has been thought, that the fissures are not from the same eruption series.Helgi Páll Jónsson: Eldfjallagarður og jarðminjasvæði á Reykjanesskaga. Jarðvísindadeild Háskóli Íslands 2011. MS ritgerð. Leiðbeinendur Ólafur Ingólfsson.
Skoðað 17. ágúst 2020. Litla-Eldborg regrettably is rather damaged by quarrying.

Tuya Geitahlíð

The pyroclastic cones bear their name, because they are located very near to the

Geitahlíð (386 m), and one of the fissures even can be seen dissecting the side of the older volcano. The tuya has its origin in subglacial eruptions under a

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 ...

glacier during a cold spell of the Ice Age. A

crater is located up on summit plateau of the tuya which produced the lava field Krýsuvíkurhraun. It entered the sea to the south and formed the upper layers at

urbjarg.

Folktales

The location is connected to the folktale about the cousins ''Krýsa'' and ''Herdís''. The old women, who could use witchcraft, had a hefty discussion about the borders of their respective lands. One wanted to cast a spell so that all the fish in a nearby lake would be hairy, and the other intended to bring up a storm and let all fishermen die, however, this did not happen. Instead, the dispute ended with the death of both cousins. The folktale maintains that they were buried side by side, and that the location of their graves is still known to locals.

Nature protection

The crater and its surroundings were placed under nature protection in 1987 as a natural monument inside of Reykjanesfólkvangur.Circumpolar protected areas monitoring. CAFF Monitoring Meeting No. 5, Report, March 2011. Retrieved 30 July 2020.
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Hiking

There are some – partially marked - hiking trails on the eruption fissure, up to the rim of the Stóra-Eldborg-Crater and in the vicinity. Reynir Ingibjartsson also proposes a tour up on the tuya through a small valley behind Stóra-Eldborg to visit the crater up on the tuya and because of the view over all of the south coast of Reykjanes as well as over other parts of Iceland's south coast up to

Eyjafjallajökull Eyjafjallajökull (; "glacier of (the mountain) Eyjafjöll"), sometimes referred to by the numeronym E15, is one of the smaller ice caps of Iceland, north of Skógar and west of Mýrdalsjökull. The ice cap covers the caldera of a volcano wi ...

External links

Stóra-Eldborg next to Geitahlíð. Visit Reykjanes. Official Travel Guide.
*The Environment Agency of Iceland
Umhverfisstofnunn.
(in Icelandic)

References

{{DEFAULTSORT:Stóra-Eldborg undir Geitahlíð Volcanoes of Iceland Volcanic craters Reykjanes Volcanic Belt Brennisteinsfjöll Volcanic System