TAPHONOMY OF MICROTEPHRA IN ENVIRONMENTAL, LACUSTRINE, AND ARCHAEOLOGICAL RECORDS: INVESTIGATING LATE HOLOCENE EXAMPLES FROM VESTFIRDIR, ICELAND

Stratigraphic layers of tephra form a geochronological record with global applications. Isochronous tephra layers can correlate a variety of paleoenvironmental, archaeological, and geological data across sites and regions, and have become increasingly important as a research tool particularly in the North Atlantic and Arctic. However, the taphonomy of microtephra can vary widely depending on the deposition environment, and this affects its use as a geochronological tool. The research presented here examines Icelandic microtephra from the Vestfirðir region in a variety of terrestrial depositional environments – lacustrine, peatland, and archaeological – and highlights several factors that influence taphonomy in each by comparison. These include the influence of water flow through microtephra-rich sediment layers in archaeologically drained peatland and the effects of spring snow- and ice-cover melting and annually sending pulses of microtephra to the lake bottom. By using records from a variety of depositional environments in the same region, differences in taphonomy of microtephra that may affect chronology building using isochrones are readily apparent. These results must be taken into account to establish an accurate and precise tephrochronology of climatic, environmental, and archaeological change in the region.