Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/128257
Type: Thesis
Title: Strontium isotope constraints on the Neoproterozoic stratigraphy of northeastern Amadeus Basin, NT, Australia
Author: Love, A. G.
Issue Date: 2017
School/Discipline: School of Physical Sciences
Abstract: We measured elemental concentrations (including rare earth elements, REEs) and radiogenic strontium isotopes (87Sr/86Sr ratios) from the Neoproterozoic carbonate-rich formations in the northeastern Amadeus Basin, in the central Australia. The acquired composite 87Sr/86Sr trend from the Amadeus Basin has the potential to be used for future strontium isotope stratigraphic (SIS) studies, in this semi-restricted intra-cratonic basin, as its local 87Sr/86Sr trend differs from the global Sr isotope seawater curve. Specifically, our composite 87Sr/86Sr trend from the Amadeus Basin is systematically more radiogenic compared to the coeval global ocean, which could be explained by a partial restriction of the Amadeus Basin during the Neoproterozoic. In particular, our elemental and isotope data show the following trends: the Ediacaran (post-Marinoan) Olympic cap carbonates (~635 Ma) revealed (i) radiogenic 87Sr/86Sr values which support the meltwater plume hypothesis and the above-mentioned basin restriction, and (ii) paleo-redox proxy data (Ce/Ce*) suggest more reducing (anoxic) conditions in the Amadeus Basin in the aftermath of the Marinoan glaciation. In contrast, the 87Sr/86Sr measurements of the Cryogenian Ringwood Member of the Aralka Formation (~658 Ma) revealed values that are approaching the global seawater 87Sr/86Sr curve, which in turn suggest relatively higher connectivity of the basin with the global ocean during this time. The paleo-redox proxy data (Ce/Ce*) from carbonates of the Cryogenian Ringwood Member and the Tonian Bitter Springs Group (~800 Ma) revealed less reducing and potentially sub-oxic conditions during these glacier-free intervals. Overall, our composite Neoproterozoic Sr isotope trend from the NE Amadeus Basin seems to mimic the global seawater 87Sr/86Sr curve, however, with a systematic offset of about ~ 0.001 to ~ 0.002 units towards more radiogenic values.
Dissertation Note: Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2017
Where: Amadeus Basin, Northern Territory
Keywords: Honours; Geology; Amadeus Basin; Neoproterozoic; carbonates; strontium isotopes; stratigraphy; paleo-redox
Description: This item is only available electronically.
Provenance: This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the author of this thesis and do not wish it to be made publicly available, or you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legals
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