AMS 14C Dating of Arctic Lake Sediments

Gifford H. Miller    gmiller@colorado.edu (Principal Investigator current)
Thomas W. Stafford (Co-Principal Investigator current)

Abstract    

     Problems associated with the radiocarbon dating of organic-carbon- poor
     arctic lake sediments have limited the utility of paleoclimatic inferences
     drawn from these repositories.  To evaluate the role of the Arctic in the
     global climate system from the geological record requires a network of sites,
     each with a secure independent geochronology.  Separation of cause and effect,
     lead and lag times, and distinguishing climate change from vegetation migration
     all require temporal resolution better than 500 years, about the limit of
     previous studies.  Although the precision of 14C measurements by accelerator
     mass spectrometry (AMS) has steadily improved during the last decade to its
     current precision of <1%, less effort has been directed at separating
     heterogeneous lake sediments into its constituent organic compounds.  The
     Paleoclimate of Arctic Lakes and Estuaries (PALE) program within the Arctic
     System Science (ARCSS) initiative requires both reliable radiocarbon dating and
     expeditious processing of samples.  This award will meet this need by providing
     a standardized sample preparation protocol for organic-carbon-poor arctic lake
     sediment based on the results of earlier research, and prioritizing sample
     handling so that basal dates for cores collected under the PALE initiative will
     be processed within 2 months of receipt.  Standardized pretreatment for PALE
     researchers will ensure an adequate number of reliable dates for each core.