01646nas a2200157 4500008004100000245011600041210006900157260001200226300001300238490000700251520111900258100001701377700001901394700002301413856005201436 2018 eng d00aFreshwater reservoir offsets and food crusts: Isotope, AMS, and lipid analyses of experimental cooking residues0 aFreshwater reservoir offsets and food crusts Isotope AMS and lip c04/2018 ae01964070 v133 a

Freshwater reservoir offsets (FROs) occur when AMS dates on charred, encrusted food residues on pottery predate a pot's chronological context because of the presence of ancient carbon from aquatic resources such as fish. Research over the past two decades has demonstrated that FROs vary widely within and between water bodies and between fish in those water bodies. Lipid analyses have identified aquatic biomarkers that can be extracted from cooking residues as potential evidence for FROs. However, lacking has been efforts to
determine empirically how much fish with FROs needs to be cooked in a pot with other resources to result in significant FRO on encrusted cooking residue and what percentage of fish C in a residue is needed to result in the recovery of aquatic biomarkers. Here we provide
preliminary assessments of both issues. Our results indicate that in historically-contingent, high alkalinity environments <20% C from fish may result in a statistically significant FRO, but that biomarkers for aquatic resources may be present in the absence of a significant
FRO.

1 aHart, J., P.1 aTaché, Karine1 aLovis, William, A. uhttp://dx.plos.org/10.1371/journal.pone.0196407