A02_04

Permafrost melt as the driver of archaeological and modern freshwater reservoir effect

Hyland C¹, Schulting R¹, Weber A², Styring A¹

¹University Of Oxford, Oxford, United Kingdom, ²University of Alberta, Alberta, Canada

Freshwater reservoir effects (FRE) are extremely varied in their driving factors which makes them challenging to correct with both high accuracy and precision. Identifying the factor(s) that have driven the incorporation of “old carbon” into freshwater environments helps researchers to improve the precision and accuracy of dating archaeological remains from important freshwater resource contexts. New insights from the radiocarbon dating and stable carbon and nitrogen isotope analysis of modern freshwater fish from the rivers surrounding Lake Baikal, Russia provide insight into the driver of this region’s modern FRE. The modern freshwater fish and previous paired dating of archaeological terrestrial faunal in direct association with human remains indicate a negative relationship exists between bulk δ¹³C values and offsets in the ¹⁴C age caused by FRE. This research proposes that both the modern and archaeological FRE is driven primarily by the incorporation of permafrost melt into these freshwater ecosystems. The permafrost melt acts as both a source of “old carbon” and a driver of low bulk δ¹³C values due to the C₃ vegetation that the permafrost contains. Additional research using stable sulfur and hydrogen isotope analysis will further examine the role of permafrost melt in the FRE of the Lake Baikal region.