Dimmuborgir: a rootless shield complex in northern Iceland

Bulletin of Volcanology
By: , and 

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Abstract

The origin of Dimmuborgir, a shield-like volcanic structure within the Younger Laxá lava flow field near Lake Mývatn, in northern Iceland, has long been questioned. New airborne laser mapping (light detection and ranging (LiDAR)), combined with ground-penetrating radar results and a detailed field study, suggests that Dimmuborgir is a complex of at least two overlapping rootless shields fed by lava erupting from the nearby Lúdentarborgir crater row. This model builds upon previous explanations for the formation of Dimmuborgir and is consistent with observations of rootless shield development at Kīlauea Volcano, Hawaii. The larger rootless shields at Dimmuborgir, 1–1.5 km in diameter, elliptical in plan view, ∼30 m in height, and each with a 500-m-wide summit depression, were capable of storing as much as 2–3 × 106 m3 of lava. They were fed by lava which descended 30–60 m in lava tubes along a distance of 3 km from the crater row. The height difference generated pressure sufficient to build rootless shields at Dimmuborgir in a timescale of weeks. The main summit depressions, inferred to be drained lava ponds, could have emptied via a 30-m-wide × 5-m-deep channel, with estimated effusion rates of 0.7–7 m3 s−1 and minimum flow durations of 5–50 days. We argue that the pillars for which Dimmuborgir is famed are remnants of lava pond rims, at various stages of disintegration that formed during pond drainage.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Dimmuborgir: a rootless shield complex in northern Iceland
Series title Bulletin of Volcanology
DOI 10.1007/s00445-016-1032-5
Volume 78
Issue 40
Year Published 2016
Language English
Publisher Springer
Contributing office(s) Volcano Science Center
Description 14 p.
Online Only (Y/N) N
Additional Online Files (Y/N) N