A new high-resolution Holocene tephra stratigraphy in eastern Iceland: Improving the Icelandic and North Atlantic tephrochronology

作者：Gudmundsdottir Esther Ruth^*; Larsen Gudrun; Bjorck Svante; Ingolfsson Olafur; Striberger Johan

来源：Quaternary Science Reviews, 2016, 150: 234-249.

DOI：10.1016/j.quascirev.2016.08.011

• Tephra stratigraphy
• Tephrochronology
• Tephra markers
• Lake Logurinn
• Iceland
• Holocene

A new and improved Holocene tephra stratigraphy and tephrochronological framework for eastern and northern Iceland is presented. Investigations of a sediment sequence from Lake Logurinn have revealed a comprehensive tephra record spanning the last 10.200 years. A total of 157 tephra layers have been identified, whereof 149 tephra layers have been correlated to its source volcanic system using geochemistry, stratigraphy and age. Fifteen layers have chemical composition of two affinities that possibly represent two very closely spaced eruptions. Thus, these 157 tephra layers are believed to represent 172 explosive eruptions. Nineteen tephra marker layers have been identified in the Lake Logurinn record (G1922, A1875, V1477, V1410, H1636, K1625, O1362, G1354, K1262, V874, Hrafnkatla, Sn-1, Grakolla, HY, H3, H4, HO, LL1755 and Reitsvik-8 tephra markers). New potential tephra markers are the silicic Askja L (similar to 9400 cal BP), the low titanium basalt layers, LL 1774 (similar to 10.150 cal BP) and LL 1755 (similar to 9990 cal BP), assigned to Veidivotn-Bardarbunga and the tephra layers, LL 1527.8 (similar to 7850 cal BP), LL 911.2 (similar to 2370 cal BP), LL 908.4 (similar to 2350 cal BP), LL 781.9 (similar to 1930 cal BP), LL 644.4 (similar to 1480 cal BP), not yet correlated to a source volcanic system. A silicic tephra marker layer, Reitsvik 8, correlated to the Fosen tephra in Norway has been identified in Lake Logurinn. The Lake Logurinn tephra record has been connected and integrated with the Icelandic terrestrial tephrochronology and stratigraphy through 102 tephra layers, the marine tephra stratigraphy through 39 layers and overseas through 9 tephra layers. This record is the first high-resolution tephra stratigraphical and chronological framework for the Holocene in eastern Iceland as well as the most detailed and continuous record, and has considerable potential to serve as a key section or a stratotype for the Holocene in eastern Iceland and the North Atlantic.

• 出版日期2016-10-15