Ljósufjöll
Template:Short description Template:Infobox mountain Ljósufjöll (Script error: No such module "IPA".) is a fissure vent system and central volcano on the Snæfellsnes Peninsula in Iceland. The name derives from the central volcano and translates into English as "Mountains of the Light".
Geography
The volcanic system has a length of about Template:Cvt and a maximum width at its eastern end of about Template:Cvt.[1] The north-western part of the Ljósufjöll volcanic system has hyaloclastite hills and lava flows about Template:Cvt wide.[1] This progresses into the ridge like central volcano with its highest peak of Template:Cvt.[1] The fissure swarm widens to the south-east and extends towards the Haffjarðará river and the town of Bifröst at the eastern base of the peninsula.
Geology
The volcanic system is part of the Snæfellsnes volcanic belt (zone). This is an intra-plate volcanic zone less than 3.3 million years old, erupting through Template:Cvt of crust at Ljósufjöll.[2] The belt has relatively low geothermal gradients for Iceland at about Template:Cvt and erupts alkalic to transitional basalts, [2] with the Ljósufjöll system tending to be less alkalotic.[1]
The Ljósufjöll volcanic system's oldest rocks are about 780,000 years old.[1] It contains cinder cones and is the only system on the peninsula that has erupted in recorded history, in 960 CE ± 10.[3] This produced from a single crater a Template:Cvt lava flow called Rauðhálsahraun Script error: No such module "IPA"., and a tephra scoria layer that covered about Template:Cvt.[1] In this region of the system to the east, the younger basaltic formations often do not entirely cover the older Neogene basement rocks.[1]
The central volcano in the system is highly silicic with the largest Quaternary rhyolitic outcrop in the Snæfellsnes volcanic belt, which causes a light coloration to the volcanoes rocks. The central volcano has erupted twice in the last 4000 years.[1] The fissure swarm has produced about 17 basaltic lava flows during the Holocene with the largest covering Template:Cvt.[2] The most studied eruption of the system is one that occurred about 4000 years ago, called the Berserkjahraun Script error: No such module "IPA". eruption, near the north-west coast of the Snæfellsnes Peninsula. The four craters are in a west to east alignment and are known as Kothraunskúla Script error: No such module "IPA"., Smáhraunskúlur Script error: No such module "IPA"., Gráakúla Script error: No such module "IPA". and Rauðakúla Script error: No such module "IPA"..[2] This must have had magma that evolved in two different storage zones, presumably one in the lower crust and one in the upper-mid-crust so as to be consistent with other findings in the Snæfellsnes volcanic belt.[2] The studies done have included the Vatnafell Script error: No such module "IPA". tuya, which is between the western portion of the definitely assigned Ljósufjöll volcanic system and the Helgrindur volcanic system and might belong to either system.[4]
Activity
Seismic activity increased at a depth of between Template:Cvt near Grjótárvatn Script error: No such module "IPA"., which is within the area of the volcanic system, in late 2024. This could be due to magma accumulation at depth or intra-plate tectonic movement.[5]
See also
References
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External links
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