Browsing by Author "Dickens, G"

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    AMS C14 dating using pollen concentrate for sediments with low organic content in the tropics of Australia
    (Elsevier, 2007-07) Moss, PT; McTainsh, GH; Dunbar, GB; Dickens, G; Jacobsen, GE
    This study discusses the results of using pollen concentrate for AMS C14 dating of sediments with low organic content for two sites in the tropical north of Australia. The first site from the Mitchell Plateau in the Kimberly region of Western Australia is a swamp deposit within a small enclosed drainage basin, with a high content of inorganic sediments. Seven AMS C-14 dates have been obtained for the first 70 cm of this record, which provides a relatively consistent age chronology that stretches back 1670 BP and can be directly compared with pollen data from the same depths. The second site, ODP 820, from the humid tropics region of northeastern Queensland consists of marine sediments with high values of Calcium Carbonate. Several AMS C-14 on foraminifera have been obtained for this record, which provide a consistent age chronology for the first 8 m of the core and which is thought to cover the last 44,000 BP. More recently, seven AMS C-14 dates based on pollen concentrate have been obtained and have been directly compared with the forminiferal derived ages, as well as the core’s pollen record. The dates and concurrent pollen data provide a better understanding of the sedimentological processes, both marine and terrestrial, that have been operating in the region, as well as providing insight into the nature of the reworking of pollen grains in marine sediments.
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    Comparative ages of pollen and foraminifera in the ODP 820 marine core
    (Australian Institute of Nuclear Science and Engineering (AINSE), 2007-11) Moss, PT; Dunbar, GB; Dickens, G; Jacobsen, GE
    This study discusses the results of using pollen concentrate for AMS C14 dating of sediments from the Ocean Drilling Program (ODP) 820 marine core and these dates are compared with existing AMS C14 dates derived from foraminifera for the same record. This will address the question of reworking, and consequent time lag between production and deposition of pollen in the Queensland Trough, as well as providing an additional age model from the terrestrial record (i.e. pollen) that can be directly compared with the existing age model derived from marine sediments (i.e. foraminifera). In addition, these results will contribute to our ability to interpret marine palynological records and provide additional insight into the sedimentological processes operating on the northeastern Queensland continental margin.