Holocene tephrostratigraphy in Vestfirðir, NW Iceland

• Published in: Journal of Quaternary Science
• Main Authors: Gudmundsdóttir, Esther Ruth, Schomacker, Anders, Brynjólfsson, Skafti, Ingólfsson, Ólafur, Larsen, Nicolaj K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Iceland; tephra geochemistry; tephra layer frequency; tephrochronology; tephrostratigraphy; Vestfirðir; Hekla; Katla; Snæfellsjökull
• Online Access: https://pure.au.dk/portal/da/publications/holocene-tephrostratigraphy-in-vestfiroir-nw-iceland(4596c601-bb05-4039-bfcc-a06679b88e4f).html; https://doi.org/10.1002/jqs.3063

We present a tephra stratigraphical and tephrochronological record from eight lakes in Vestfirðir, NW Iceland. About 50 tephra units have been identified, representing nearly 30 eruptive events originating from five volcanic systems: Hekla, Katla, Snæfellsjökull, Grímsvötn and Veiðivötn-Bárðarbunga. Most of the tephra layers originate from Grímsvötn, although there is a prominent presence of andesitic to basaltic tephra layers from Hekla in the record. We propose that the previously described Brattihjalli tephra is actually the 6060-year-old Hekla Ö tephra marker layer, recording a more north-westerly dispersal than before and providing new correlation possibilities across Iceland. Thus, the Hekla Ö tephra covers as large an area in Iceland as the Hekla 5, Hekla 4, Hekla 3 and Hekla 1104 tephra layers, emphasizing its importance as a chronological marker. The tephra markers Hekla 1693, V877/Settlement layer, Sn-1, Hekla 3 and Hekla 4 have been found and, additionally, our study identifies four potential tephra markers, the Katla D1 ∼2750 cal a BP, Katla D2 ∼3700 cal a BP, Reykjarfjörður tephra ∼8800 cal a BP and Dagverðardalur tephra ∼9300–9500 cal a BP. Our data reveal several new tephra layers in Vestfirðir, including chronological markers important for dating and correlation.