RADIOCARBON VARIATIONS FROM TASMANIAN CONIFERS - RESULTS FROM 3 EARLYHOLOCENE LOGS

Dendrochronological studies are being carried out on two conifer speci es in the Stanley River area of western Tasmania. The chronology for H uon pine (Lagarostrobos franklinii), with living trees up to 1400 yr o ld, extends back to 571 BC. Living celery-top pine (Phyllocladus asple niifolius) trees are up to 500 yr old. Apart from living or recently f elled trees, sections have been taken from 350 subfossil logs preserve d in floodplain sediments. They range in age from >38 ka to modern, wi th good coverage for the periods 9-3.5 ka and from 2.5 ka to the prese nt. We report here on C-14 measurements of decadal samples from three early Holocene logs, between 10 and 9 ka BP, providing short (ca. 300- yr) records of atmospheric C-14 variations when plotted against ring n umbers. The southern hemisphere data from Tasmania can be compared and wiggle-matched with published C-14 calibration curves from German oak and pine. One set of measurements covers the period, ca. 9280-8990 ca l BP, overlapping the link between the Hohenheim ''Main 9'' and middle Holocene master oak chronologies. The other sets of measurements from Tasmania coincide; they span the period, ca. 9840-9480 cal BP, overla pping the end of the German Preboreal pine and the beginning of the oa k chronologies. Our measurements confirm that this part of the calibra tion curve is a gently sloping C-14-age plateau (ca. 8900-8700 sp, bet ween 10,000 and 9500 cal BP), and suggest interhemispheric C-14 differ ences close to zero.