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Cosmogenic 10Be and 26Al sample preparation at t by Alexandru T Codilean, Réka H Fülöp et al

The University of Wollongong (UOW) cosmogenic 10Be and 26Al sample preparation laboratory has been in operation since the start of 2017. As primarily a feeder laboratory to ANSTO's Centre for Accelerator Science, our sample preparation procedures have been optimised with consideration to the setup of ANSTO's 6MV SIRIUS accelerator, and aim to achieve a balance between sample throughput as well as Be and Al target purity. A comparatively small number of samples (n = 68) have also been prepared for measurement at the Australian National University 14UD accelerator. 10Be/9Be ratios of procedural blanks measured on SIRIUS have fluctuated over time with the median for the year 2017 being 5.16 × 10−16 (IQR = 4.11 × 10−16 to 7.16 × 10−16, n = 18), increasing to 1.62 × 10−15 (IQR = 1.05 × 10−15 to 2.17 × 10−15, n = 31) for 2018 and 2019, a period coinciding with elevated boron levels in our samples, and finally decreasing to 1.15 × 10−15 (IQR = 8.63 × 10−16 to

Geomorphic imprints of lithospheric flexure in central Australia by J D Jansen, M Sandiford et al

The Finke River in central Australia is counted among the world's oldest drainage systems; this raises the prospect of investigating how (tectonic and sub-lithospheric) processes have shaped the landscape in the long term. The Finke's upper reaches display an enigmatic set of intertwined active and relict bedrock gorges that suggest a complex history of incision, aggradation and re-incision. We measured cosmogenic 10Be and 26Al in fluvial gravels preserved in the gorges, and we applied a Markov chain-Monte Carlo-based inversion model to test two limiting-case hypotheses about the timing of gravel deposition and exhumation. Our results suggest that the nuclide memory contained within the gravels was essentially erased during sediment storage exceeding several million years. Previous studies attribute central Australia's geomorphic development to intensified post-Miocene aridity in tune with the perception of a quiescent tectonic regime. However, the close correlation betw

Low-altitude periglacial activity in southeastern Australia during the by Timothy T Barrows, Stephanie C Mills et al

Only a small area of the Australian mainland was glaciated during the Pleistocene, whereas periglacial deposits are far more common, indicating that cold environments were extensive and a major influence on landscape evolution. Here we identify representative low-elevation examples of scree slopes and frost action, together with fans and valley fills, indicating pronounced erosion cycles during the Pleistocene. To date the deposits, we explore approaches using radiocarbon, optically stimulated luminescence, and profile dating using the cosmogenic nuclide 10Be. The radiocarbon and optical ages show that screes, alluvial valley fill, and fans were deposited between 66-13 ka during the coldest part of the last glacial cycle, and within the previous glacial cycle. Exposure dating indicates further landscape erosion cycles back to the mid Pleistocene. Together, the deposits indicate the frost cracking limit was ∼1300 m lower at 680 ± 10 m and mean winter temperature was 8.2 ± 0.5°C col

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