Northeastern Section - 53rd Annual Meeting - 2018

Paper No. 58-11
Presentation Time: 8:00 AM-12:00 PM


RETELLE, Michael J.1, BIGELOW, Gerald F.2, AMBROSE, William G.3 and MCNAB, A. Douglas1, (1)Department of Geology, Bates College, Lewiston, ME 04240, (2)History, Bates College, 4 Andrews Road, Lewiston, ME 04240, (3)Department of Biology, Bates College, Lewiston, ME 04240

The Norse Vikings settled a large geographic region across the North Atlantic, from Scandinavia in the east as far as Greenland in the west.The relationship of the settlement histories to the extent and exact timing of climate events is heavily debated. Current estimates place the warmer Medieval Climatic Anomaly spanning ca. 900-1250 AD, while the Little Ice Age spanned the period from roughly ca. 1250-1800. The North Atlantic Norse settlements were established at the boundary of these two periods, and their histories may reflect diverse climate interactions.

The timing and magnitude of these effects have not been firmly established for the Shetland Islands, and due to their climate and soil composition, many terrestrial paleoclimate proxies are generally not viable for study. This study utilizes cod otoliths from middens at a Late Norse settlement at the Sandwick South site on the island of Unst to reconstruct a paleoclimate scenario for the area. This site was occupied between 1100 AD-1350 AD, a period which encompasses the end of the Medieval Climatic Anomaly and the transition to the Little Ice Age. Otoliths are analyzed for both 𝛅18O values and 14C AMS ages, which help to constrain the age of the middens and provide reconstructed ocean temperature.. In addition, otoliths will be cut and annual growth rings will be measured to analyze the size, age, and growth rate of the cod over the period of occupation. Analysis of fish size across the site reveals a distribution skewed towards larger fish for reconstructed fish lengths across all midden strata, with an average length of 85 cm for fish caught at the site. By combining the data describing the health of the late Holocene Norse fishery with the paleotemperature data for the ocean around the Shetland Islands, a paleoenvironmental reconstruction facilitate assessment of possible reasons for economic and other changes to the settlement, including the desertion of the settlement at approximately AD 1400.