Dispersal, source and glass chemistry of a third tephra unit within Iceland's Settlement Layer
2026/07/26 by Conner A. G. Morison, Gudrun Larsen, GuÐrún Larsen +4
Earth and Planetary Sciences · Physics and Astronomy · #Geology and Paleoclimatology Research #Geological and Geochemical Analysis #Planetary Science and Exploration
paper · doi:10.1111/bor.70079
Abstract
Tephra layers may be studied to understand the dynamics and sequence of past explosive volcanism. In Iceland, the distinctive Settlement Layer (AD ~877) underlies almost all archaeological evidence for the Norse Settlement and is preserved in soils across Iceland and as cryptotephra overseas. It comprises an olive‐green, tholeiitic basalt unit erupted from the Vatnaöldur crater row (within the Veiðivötn fissure swarm) and a white transitional alkali rhyolite unit from the Hrafntinnuhraun craters (within the Torfajökull complex). This paper describes a previously undocumented, dark‐grey tephra unit that we discovered in the Búland landholding (Skaftárhreppur). Electron probe micro‐analyses determined that this tephra unit is a bimodal transitional alkali basalt. Although it was deposited less than a year before the Vatnaöldur unit, it is unclear whether it also preceded the Hrafntinnuhraun unit. Nonetheless, we use the unit's thickness and composition to infer the likely origin to be Skyggnishlíðarvötn, a triplet of maar craters SW of the Torfajökull complex. The major‐/minor‐oxide composition of tephra collected from within the crater rim of the Skyggnishlíðarvötn maars (~45 km WNW of Búland) is indistinguishable from that of the unit we recorded near Búland. These findings demonstrate that volcanic unrest in the Veiðivötn fissure swarm is associated with explosive basaltic volcanism in the Torfajökull complex. The Skyggnishlíðarvötn phase may well have acted as a precursor to the impending Settlement eruption sequence.
Citations
- Late survival of woodland contrasts with rapid limnological changes following settlement at Kalmanstjörn, Mývatnssveit, northeast Iceland
- A catalogue of major and trace element data for Icelandic Holocene silicic tephra layers
- Tephra productivity and eruption flux of the subglacial Katla volcano, Iceland
- Correlating tephras and cryptotephras using glass compositional analyses and numerical and statistical methods: Review and evaluation
- A high-resolution multi-proxy lake record of Holocene environmental change in southern Iceland
- Tephrochronology and the late Holocene volcanic and flood history of Eyjafjallajökull, Iceland
- The Peopling of Iceland
- Vegetational response to human colonisation of the coastal and volcanic environments of Ketilsstaðir, southern Iceland
- Two millennia of glacier advances from southern Iceland dated by tephrochronology
- Late Quaternary terrestrial tephrochronology of Iceland—frequency of explosive eruptions, type and volume of tephra deposits
- Katla volcano, Iceland: magma composition, dynamics and eruption frequency as recorded by Holocene tephra layers
- A Holocene tephra record from the Lofoten Islands, Arctic Norway
- Tephrological implications of beam size—sample‐size effects in electron microprobe analysis of glass shards
- Petrogenetic Evolution of the Torfaj kull Volcanic Complex, Iceland II. The Role of Magma Mixing
- Petrogenetic Evolution of the Torfaj kull Volcanic Complex, Iceland I. Relationship Between the Magma Types
- Timescales of magma differentiation from basalt to andesite beneath Hekla Volcano, Iceland: Constraints from U-series disequilibria in lavas from the last quarter-millennium flows
- Chemistry and distribution pattern of recent basaltic rocks in Iceland
- Charcoal Production During the Norse and Early Medieval Periods in Eyjafjallahreppur, Southern Iceland
- The Icelandic ?rofabard? soil erosion features
- Electron probe technique for characterising pyroclastic deposits
- Ash layers from Iceland in the Greenland GRIP ice core correlated with oceanic and land sediments
- The Norse landnám on the North Atlantic islands: an environmental impact assessment
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