Volcanism in the Arctic System — VAST

This is an international effort that focuses on refining the Icelandic tephrochronology and evaluating the impact of volcanism on the Arctic System. The team will center on the impacts of volcanism on the Arctic system utilizing climate models, and to better utilize the time synchronization offered by tephrochronology, particularly in Iceland, to evaluate leads and lags in the climate system. The aim is to reconstruct a detailed and accurate age model for paleoclimatic records covering the Holocene (the last ca. 12000 years). The foundation for this age reconstruction will be Icelandic tephra deposits. This effort is strongly international with other Arctic-rim countries around the North Atlantic.

Specific objectives include:

• Establish a standardized geochemical inventory of key Icelandic marker tephra layers in the last 12,000 years and refine the late-glacial to early Holocene tephrochronology in Iceland utilizing existing cores recovered during the GLAD-4 campaign in 2003 and new lake sediment cores.
• Extend proximal-derived geochemical fingerprinting to microtephra in distal archives (northern North Atlantic and Nordic Seas marine sediment cores, lake sediment cores from select sites in NW Europe and Arctic Canada, and Greenland ice cores)
• Refine paleoclimate records from Iceland for the past 12,000 years to constrain Holocene climate variability and forcing.
• Quantify major atmospheric volcanic aerosol loading derived from the geochemical analyses of the NGRIP Greenland ice core
• Evaluate the sensitivity of the Arctic System to high and low latitude eruptions through a comparison of paleoclimate reconstructions and climate modeling.
• A specific deliverable will be a public database listing the key marker tephra layers, their physical attributes as well as their major, trace and rare earth element composition determined on samples from established reference sites.
It will also include standardized protocols for sample preparation and analytical procedures.