Reconstructing Late Pleistocene Atmospheric Radiocarbon using Subfossil New Zealand Kauri (Agathis australis)

Ms Priyadarshini Parsons O’brien1, Prof. Chris  Turney1, Dr.  Jonathan Palmer1, Dr.  Pavla  Fenwick2, Prof. Alan Hogg3, Dr.  Andrew  Lorrey4, Dr.  Quan Hua5

1Chronos 14Carbon-Cycle Facility, and Earth and Sustainability Science Research Centre, University of New South Wales, Sydney, Australia, 2Gondwana Tree-Ring Laboratory, Little River, New Zealand, 3Radiocarbon Dating Laboratory, University of Waikato, Hamilton, New Zealand, 4National Institute of Water and Atmospheric Research Ltd, Auckland, New Zealand, 5Australian Nuclear Science and Technology Organisation, Kirrawee, Australia

Subfossil New Zealand kauri (Agathis australis) buried in bogs across Northland, New Zealand, provide considerable potential for a continuous high-precision radiocarbon calibration curve that extends across the full range of radiocarbon dating. Kauri currently is a significant contributor to our understanding of calibration in this Southern region. The preserved samples also offer a unique opportunity to reconstruct climate events on multi-millennial timescales with annual resolution and carbon concentration. Here we investigate a key site called Waipu, where 40 subfossil trees have been crossdated to form 5 floating chronologies. These series cover collectively 6000 years and preliminary radiocarbon dating suggests a range of ages from 22,000 to 49,000 years BP. Further radiocarbon dating and crossdating of other kauri tree-ring series using the new RingdateR package and visual inspection has identified other trees that may cross-date. This suggests it may be possible to link the floating Waipu series, forming a continuous chronology.If successful this would form the one of the longest subfossil kauri chronologies, with the help of radiocarbon dating. The Waipu chronology would form a world-class palaeo-archive for the Southern Hemisphere and provide a valuable contribution to future iterations of the international calibration curves.


Biography:

Priyadarshini (Priya) Parsons O’Brien is currently completely her PhD in Geography focusing on dendrochronology and radiocarbon dating. Last year she completed her undergraduate with honours in Advanced Science majoring in Geography and minor in Paleosciences.

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Date

Nov 16 2021

Time

TUESDAY
10:45 am - 11:30 am