A Laacher See-eruption supplement to Tephrabase: Investigating distal tephra fallout dynamics

Tephrabase (www.tephrabase.org) is an online data repository and research tool for tephrochronological investigations in northern Europe. This paper presents and discusses an update to Tephrabase that contains geographic and, as far as available, geochemical data on 452 data-points for the widespread isochronous Laacher See tephra. This tephra is dated to c. 12,920 calendar years BP and acts as an important chronostratigraphic marker for the Lateglacial GI-1a/late Allerød chronozone in terrestrial and lacustrine palaeoenvironmental archives as well as in archaeological stratigraphies. Based on these data, a revised map of the total tephra distribution is presented, suggesting that the north-eastern fallout lobe might contain a secondary fallout thickness maximum, 230–340 km distant from the eruptive centre. In addition, new geochemical data from a series of distal tephra deposits spanning most of the north-eastern fallout lobe are used to evaluate previous suggestions regarding the distribution of fallout from distinct eruption phases. The aim of the study is that future tephrochronological investigations can use this database and the revised distribution map for effectively targeting sites for analysis.