Variations in marine reservoir corrections for the Great Barrier Reef during the last 7000 years
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Date
2011-03-21
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12th International Conference on Accelerator Mass Spectrometry (AMS-12)
Abstract
For calibration of marine 14C ages, marine reservoir correction value (ΔR) of a given location is generally assumed to be constant with time. However, variations in the marine reservoir effect of several hundred to a couple of thousand years have been observed for various regions in the Pacific, Atlantic and Mediterranean during the Late-glacial and Holocene. These variations result from changes in ocean circulation and the carbon cycle associated with climate change. Here we present a new data set of ΔR for the Great Barrier Reef (GBR) in south-western Pacific Ocean during the last 7000 years for the investigation of possible variability in the marine reservoir effect of this area and for improving radiocarbon dating of marine samples. Coral samples used in this study were from shallow cores and storm derived blocks collected on Heron Reef in southern GBR at 23º26'S, 151º55'E. Fifteen unaltered coral samples (based on SEM screening, δ234U and initial 230Th/232Th ratios) were analysed for 230Th/U and 14C. 230Th dates were determined by TIMS Useries in the Radiogenic Isotope Laboratory at the University of Queensland with a precision better than 0.5% (2σ). Aliquots of these dated corals were then taken for radiocarbon analysis. The samples were cut by diamond saw, cleaned in deionised water, oven dried, and homogenised in a mortar and pestle prior to 14C analysis using the STAR AMS facility at ANSTO. A typical precision for 14C analysis is <0.4% (1σ). The results of this investigation will be compared with those of previous studies for the Pacific, and variations in ΔR for the GBR for the mid- to late Holocene and their possible mechanisms will be then discussed. This work was supported by AINSE grant 09/056. Copyright (c) 2011 AMS12.
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Keywords
Calibration, Carbon 14, Quaternary period, Climatic change, Pacific Ocean, Reefs
Citation
Hua, Q., Webb, G., Zhao, J., Nothdurft, L., Price, G. (2011). Variations in Marine Reservoir corrections for the Great Barrier Reef during the last 7000 years. Presentation to the 12th International Conference on Accelerator Mass Spectrometry (AMS 12), 20th - 25th March 2011. Museum of New Zealand: Te Papa Tongarewa, Wellington, New Zealand, (pp. 31).