Radiometric Dating of subglacial carbonates from Antarctica, Elephant Moraine and Boggs Valley, 2016-2021

Full description

This dataset relates to the U/Th ages of Elephant Moraine samples illustrated in https://data.aad.gov.au/metadata/AAS_4558_Subglacial_Carbonates_Samples

The petrographic characteristics are archived in:
https://data.aad.gov.au/metadata/AAS_4558_optical_microscopy

Additional chemical data coupled with back-scattered electron (BSE) imaging of the specimens consisting of black calcite are stored in:
https://data.aad.gov.au/metadata/AAS_4558_Microprobes

For Boggs Valley, samples are illustrated in Frisia et al., (2017). Here, the details of single age datapoints are provided here in the folder Boggs Valley, in pdf format. This allows researchers to check where the ages (and in particular those related to cements in clastic layers) come from (a piece of information that was not given in Frisia et al., 2017).
Please, note that the U/Th ages of the Elephant Moraine are given as non-corrected, as correction may, somewhat, induce a margin of subjectivity. The uncertainty in the ages of the Elephant Moraine is, in fact, so large that the U-Th ages can be corrected to yield ages for columnar crystals spanning from ca. 250,000 to (possibly) greater than 500,000 years or even a million. This is also due to the fact that there is not much U in the Elephant Moraine samples.

U/Th dating was performed by multi-collector ICP-MS at the School of Earth Sciences, the University of Melbourne, following the analytical method described in Hellstrom (2003). Age uncertainties are likely due to detrital Th contamination.


By contrast, the Boggs Valley samples have a high amount of U (ca. 50 ppm), whereby ages are reliable and constrained between ca. 27,000 and 70,000 years ago. Thus, we decided to perform 3 radiocarbon dating (not included in the original proposal) by using the ANTARES accelerator Mass Spectrometer facility at ANSTO following the protocol in Hua et al., 2001. Radiocarbon activity provides information about potential connections with the atmosphere and radiocarbon dating is effective in samples younger than 50,000 years, which is the case of the Boggs Valley calcites.
The results are reported in the folder Bogs Valley.

Lineage

Progress Code: completed

Statement: Some data still have to be extracted due to the closure of University of Melbourne facilities during COVID lockdowns.