The older a sample is, the less (the period of time after which half of a given sample will have decayed) is about 5,730 years, the oldest dates that can be reliably measured by this process date to around 50,000 years ago, although special preparation methods occasionally permit accurate analysis of older samples.
The idea behind radiocarbon dating is straightforward, but years of work were required to develop the technique to the point where accurate dates could be obtained.
Laser ablation involves the use of incident light to remove material from a solid surface.
When coupled with mass spectrometry it is a powerful tool for quantitative chemical analysis.
Isotopic dating of calcite has important industrial applications and also permits dating of carbonate rocks from key time periods in the ancient geological record, before the appearance of hard-bodied fossils.” Present approaches to U-Pb dating of calcite suffer from large age uncertainties due to low U concentrations and/or high amounts of initial Pb.
Dr Chew’s work will generate U/Pb image maps that facilitate identification of high and low U/Pb portions of the rastered area, which can be sub-sampled to yield a sufficient spread on isochrons to yield U-Pb calcite age uncertainties as low as ±1%.
The Investigators Programme, with its focus on scientific excellence and impact will place Ireland’s researchers in a strong position to compete for Horizon 2020 research grants.
Small fossilized cyanobacteria have been extracted from Precambrian rock, and studied through the use of SEM and TEM (scanning and transmission electron microscopy).
Ancient Fossil Bacteria : Pictured above are two kinds cyanobacteria from the Bitter Springs chert of central Australia, a site dating to the Late Proterozoic, about 850 million years old.
On the left is a colonial chroococcalean form, and on the right is the filamentous Palaeolyngbya. Small concentrically layered structures called pisolites are also the result of fossilized bacteria.
Cyanobacteria are otherwise rarely preserved in rocks other than chert, though some possible blue-green bacteria have been recovered from shale.