AMS radiocarbon calibration results.

Bulk sediment accelerator mass spectrometry (AMS) radiocarbon results calibrated using the IntCal04 Southern Hemisphere Curve [24]. 14C ages are reported as conventional radiocarbon years BP (AD 1950). Calibrated age ranges are reported as 2σ Weighted Average standard deviations of the calibrated files. These ages are rounded to the nearest 5-year interval. This calibration assumes no influence from marine carbon due to the reequilibriation of CO2 from the atmosphere in the shallow lagoon water (max 1 m deep) [26]. As a result even submerged aquatic lagoon samples would have acquired the bulk of their organic carbon from atmospheric sources.