Journal article

Accurate dating of stalagmites from low seasonal contrast tropical Pacific climate using Sr 2D maps, fabrics and annual hydrological cycles

Mohammadali Faraji, Andrea Borsato, Silvia Frisia, John C Hellstrom, Andrew Lorrey, Adam Hartland, Alan Greig, David P Mattey



Tropical Pacific stalagmites are commonly affected by dating uncertainties because of their low U concentration and/or elevated initial 230Th content. This poses problems in establishing reliable trends and periodicities for droughts and pluvial episodes in a region vulnerable to climate change. Here we constrain the chronology of a Cook Islands stalagmite using synchrotron µXRF two-dimensional mapping of Sr concentrations coupled with growth laminae optical imaging constrained by in situ monitoring. Unidimensional LA-ICP-MS-generated Mg, Sr, Ba and Na variability series were anchored to the 2D Sr and optical maps. The annual hydrological significance of Mg, Sr, Ba and Na was tested by princ..

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Awarded by Australian Research Council Discovery Project

Awarded by Australian Institute of Nuclear Science and Engineering

Funding Acknowledgements

Many thanks to the Cook Islands Meteorological Service for granting us permission to access historic precipitation data held at NIWA for this work. We are grateful to Roger Malcom (Atiu Villas) for providing the precipitation data for Atiu. Special thanks to Tura Koronui and George Mateariki who introduced us to the caves in Atiu. Garry Smith participated in previous fieldwork campaigns. The SR-micro XRF analyses were undertaken at the X-ray fluorescence microscopy (XFM) beamline at the Australian Synchrotron, Victoria, Australia, with the assistance of Daryl Howard. This study was supported by the Australian Research Council Discovery Project Grant DP160101058. M.F. was supported by the Australian Government through an "Australian Government Research Training Program Scholarship", and was supported also by The Australian Institute of Nuclear Science and Engineering through a Postgraduate Research Award (award ALNSTU12486).