USING RADIOCARBON AGES ON ORGANICS AFFECTED BY FRESHWATER—A GEOLOGIC AND ARCHAEOLOGIC UPDATE ON THE FRESHWATER RESERVOIR AGES AND FRESHWATER DIET EFFECT IN MANITOBA, CANADA

Abstract

ABSTRACTFreshwater reservoir ages and a potential freshwater diet effect are examined for Manitoba (Canada), using paired samples of contemporaneous terrestrial, freshwater, and omnivore-diet species (Homo sapiens, Gavia sp.). The freshwater diet effect (n=4) varies from 220 to 370 14C years. The FRE (n=12) is temporally variable, with a median of 230 14C years and values up to 880 14C years (or more). Understanding the FRE is important for geologists who reconstruct the postglacial history of an area. It is also important for archaeologists who rely on 14C dating to develop cultural histories, as inhabitants of the Canadian boreal forest have relied upon freshwater resources as a part of their diet. An analysis of the δ13C on 93 freshwater mollusk samples from 11 species demonstrates significant variability, which highlights the difficulty in assigning an “assumed” fractionation correction.