Radiocarbon Dating by Accelerator Mass Spectrometry; A Contribution to the Chronology of Holocene Events in Nordaustlandet, Svalbard

Seventeen 14C age determinations by accelerator mass spectrometry (AMS) have been carried out on individual fragments of marine shells from Nordaustlandet, Svalbard. Aside from a Holocene control sample only six of the shells, mainly from moraine ridges associated with present-day glaciers, are of Holocene age. The most interesting results are dates of 9180 ± 130 years BP (Ua-672), 9525 ± 130 years BP (Ua-905) and 9675 ± 140 years BP (Ua-1058) on shell fragments from an interbobate moraine between Vestfonna and Sere Franklin- breen. The site is 6 km behind the calving front of Søre Franklinbreen.Six of the remaining eleven samples are >40 000 years old. A date from the same interlobate moraine between Søre Franklinbreen and Vestfonna gave 34 700 ± 810 years (Ua-345), but it seems safest to regard this value as a minimum age also. The same is true of dates of 35 230 ± 790 years (Ua-670) from till-like material within an area of raised beaches in Jäderinfjorden and 38 100 ± 1070 years (Ua-673) from till-like material underlying beaches on Wargentinflya southwest of Lady Franklinfjorden. The dates indicate that several anomalous ages determined previously, six in the 13 000 to 23 000 year-range and one close to 30 000 years, are the result of mixing of Holocene-aged shells with old' shells. The results also show that at least two of the main outlet glaciers from Vestfonna were much reduced in size in early Holocene time.