Explosive, voluminous volcanic eruptions can alter the Earth’s radiative balance, causing substantial perturbation to the Arctic System. Widespread tephras from explosive eruptions are key marker beds that allow for near-instantaneous chronostratigraphic constraints in terrestrial, marine, and ice archives. In the North Atlantic, Iceland is the foremost source for wide-spead Quaternary tephras. Tephras from select eruptions in Iceland have been detected in marine and terrestrial sediment archives throughout the northern North Atlantic, however their progressively finer dispersal leaves many tephras concealed in distal archives due to their low abundances and fine grain sizes.

New data at sub-millimeter resolution obtained by the ITRAX non-destructive X-ray fluorescence (XRF) core scanner now allows for the detection of cryptotephra – tephra not visible to the naked eye. This study uses the ITRAX micro-XRF scanner to develop a new analytical approach to easily discern cryptotephras in distal lacustrine archives. In order to target cryptotephras in actual sediment cores, “synthetic cores” are created to replicate cryptotephra deposition in lacustrine material (Figure 1). These cores use as known quantities of archetypal lacustrine sediments, as well as known quantities of cryptotephras from specific explosive Icelandic eruptions over a range of chemical compositions. The synthetic cores are spiked with cryptotephras at known intervals, and then anaylized with the ITRAX micro-XRF scanner.

Preliminary ITRAX results indicate a possible detection of cryptotephras within synthetic lacustrine laminae. Statistical analyses are currently underway to calculate the optimum ratio of elements to constrain and distinguish cryptotephras of varying compositions from surrounding lacustrine background materials. This analytical approach will be applied to actual lacustrine cores from Baffin Island and other sites distal to Icelandic eruptive centers, serving as a mechanism of age-dating and correlation among sediment records in the Arctic.