High-Resolution Age Model Based on AMS Radiocarbon Ages for Kettle Lake, North Dakota, USA

Eric C Grimm
2011 Radiocarbon: An International Journal of Cosmogenic Isotope Research  
A high-resolution age model was developed for Kettle Lake, North Dakota, USA, from a series of 53 accelerator mass spectrometry (AMS) radiocarbon ages calibrated with Bayesian statistical methods, which provide a monotonically increasing series of calibrated ages with depth. Evident in the sediment are several slumps, debris flows, or landslides, which are confirmed by14C dating. Removal of these facies produces a continuous sedimentary sequence for the past 13,000 yr with exception of one
more » ... yr hiatus associated with a 1.5-m-thick slump deposit. All ages except one are on terrestrial macrofossils and charcoal. A test age on aquatic organic detritus shows a hardwater effect of 600 yr at ≃2000 cal BP. Two ages from the same level on herbaceous charcoal andChenopodiumseeds are statistically the same, which further demonstrates the suitability of charcoal from grassland environments for AMS14C age control. However, 2 specimens of wood charcoal are too old relative to bracketing ages and glacial geologic history. These ages confirm the sedimentary interpretation of redeposition and provide a caution about the longevity of wood charcoal in the environment and its suitability for age control in lacustrine sediments.
doi:10.1017/s0033822200034342 fatcat:m6za424d75hnxkqpau5m2hdule