QUANTIFYING CONTEXT: INTEGRATING PXRF CHEMOSTRATIGRAPHY AND THIN-SECTION MICROMORPHOLOGY AT SKAGAFJÖRÐUR, NORTHERN ICELAND

Using stratigraphy to discern contextual associations of artifacts and their associated sediment matrices is fundamental to geoarchaeological inquiry. Traditionally, this approach is a subjective endeavor whereby archaeologists assess stratigraphic integrity via verbal and visual approximations in the field. We describe an approach aimed at quantifying these approximations through the application of both pXRF and thin-section micromorphology to sediments yielded from Viking Age farm-middens located in Skagafjörður, northern Iceland. Thin-sections were taken at the contacts of lithostratigraphic units, and bulk sediment samples (200g) were taken from above and below these contacts. By using micromorphology to identify major minerals within sediment deposits at the site of Syðra-Skördugil, we were able to calibrate our pXRF device and construct the chemostratigraphic framework. A total of 60 pXRF readings were analyzed using multiple discriminate function analysis, resulting in a 92.8% classification rate. Further micromorphological analysis of unclassified units revealed evidence of mixing, highlighting the power of a combined approach. These data suggest that a combined application of both pXRF chemostratigraphy and micromorphology provides a novel way to quantify and assess complex stratigraphic frameworks at archaeological sites.