Product catalogue
Characterization of uranium redox state in organic-rich marine sediments of the Cretaceous Toolebuc Formation, Australia
<div>Throughout geological history, marine organic-rich shales show variable but appreciable enrichment in uranium (U), < 5 to > 500 ppm. Here we report the results of high-energy resolution fluorescence detection (HERFD) x-ray absorption spectroscopy at U L3 and M4 edges to characterize U speciation in marine sediments.</div><div><br></div><div>We characterised U oxidation state in samples from the Cretaceous Toolebuc Formation of the Eromanga Basin, Australia. Nine samples were carbonaceous shales with high total organic carbon (TOC) content of 5.9 to 13.4 wt % and with low maturity organic matter. Two samples of coquinite were selected for comparison (TOC 0.3 and 2.4 wt %).</div><div><br></div><div>Our results suggest that a significant proportion of U in marine black shales (~20 to 30%) exists as U(VI) (Figures 1-2), despite the extremely reducing (anoxic to euxinic) conditions during sediment precipitation and diagenesis. Within individual samples, spot analyses indicate variation in the estimated oxidation state within a range of ~20% of U(VI). Uranium is unevenly distributed at mm to nanoscale. Nanoscale secondary ion mass spectrometry (NanoSIMS) reveals different associations that often coexist in single samples; nano-particulate uranium is associated with organic matter matrix or sulphide minerals, whereas phosphate minerals display diffuse uranium enrichment. The coquinite has a higher proportion of U(VI), consistent with the dysoxic depositional environment (Boreham and Powell, 1987).</div><div><br></div><div>The unexpectedly enhanced proportion of U(VI) relative to U(IV) within marine organic-rich shales implies that U might not be immediately fixed by reduction processes during sedimentation, but adsorbed by accumulating organic matter, at least in part as U(VI). This is consistent with the behaviour of uranium reported within the water column of the anoxic Black Sea (Anderson, 1989), experiments on U(VI) sorption by organic matter (e.g., Bhat et al., 2008), and previously documented redox state of U from continental organic-rich Eocene (56-34 Ma) sediments of paleochannel and lacustrine origin (Cumberland et al., 2018).</div><div><br></div><div>The results are significant for improving hydrocarbon exploration in known fields (covering the gap to a carbon-free economy without development of new greenfield oil provinces); economic geology (uranium, base-metal, and critical-metal deposits); and environmental management (evaluating potential mobilization of U by groundwaters).</div><div><br></div>This Abstract was submitted and presented to the 2023 Goldschmidt Conference Lyon, France ( https://conf.goldschmidt.info/goldschmidt/2023/meetingapp.cgi)
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Identification info
- Date (Creation)
- 2023-03-01T07:00:00
- Date (Publication)
- 2023-09-19T22:08:10
- Citation identifier
- Geoscience Australia Persistent Identifier/https://pid.geoscience.gov.au/dataset/ga/147753
- Cited responsible party
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Role Organisation / Individual Name Details Publisher Commonwealth of Australia (Geoscience Australia)
Voice Author Bastrakov, E.
Internal Contact Author Brugger, J.
External Contact Author Etschmann, B.
External Contact Author Bazarkina, E.
External Contact Author Kvashnina, K.
External Contact Author Proux, O.
External Contact Author Testemale, D.
External Contact Author Boreham, C.
Internal Contact Author VanDerWielen, S.
Internal Contact Author Guagliardo, P.
External Contact
- Name
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Goldschmidt Conference 8-14 July 2023 Lyon, France
- Purpose
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Goldschmidt 2023 Conference: Presentation of novel analytical results to a broad scientific community
- Status
- Completed
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Role Organisation / Individual Name Details Resource provider Minerals, Energy and Groundwater Division
External Contact Point of contact Commonwealth of Australia (Geoscience Australia)
Voice Point of contact Bastrakov, E.
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- Geoscientific information
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Product data repository: Various Formats
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EFTF – Exploring for the Future
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- Keywords
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Geochemistry
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- Keywords
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Unconventional Hydrocarbons
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- Keywords
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trace elements
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- theme.ANZRC Fields of Research.rdf
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Inorganic Geochemistry
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Organic Geochemistry
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Geochemistry not elsewhere classified
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- Keywords
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Published_External
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Creative Commons Attribution 4.0 International Licence
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CC-BY
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4.0
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© Commonwealth of Australia (Geoscience Australia) 2023
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Australian Government Security Classification System
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- 2018-11-01T00:00:00
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- Unclassified
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Australian Government Security Classification System
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- English
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- UTF8
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Role Organisation / Individual Name Details Distributor Commonwealth of Australia (Geoscience Australia)
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<div>N/A</div>
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- Title
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Australian Government Security Classification System
- Edition date
- 2018-11-01T00:00:00
- Classification
- Unclassified
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- Metadata identifier
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urn:uuid/c2b536e3-ae12-4f03-b4ae-fcc7f7087b46
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GeoNetwork UUID
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Role Organisation / Individual Name Details Point of contact Commonwealth of Australia (Geoscience Australia)
Voice Point of contact Bastrakov, E.
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Conference Abstract
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Geoscience Australia - short identifier for metadata record with
uuid
- Citation identifier
- eCatId/147753
- Date info (Creation)
- 2023-09-19T21:54:58
- Date info (Revision)
- 2023-09-19T21:54:58
Metadata standard
- Title
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AU/NZS ISO 19115-1:2014
Metadata standard
- Title
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ISO 19115-1:2014
Metadata standard
- Title
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ISO 19115-3
- Title
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Geoscience Australia Community Metadata Profile of ISO 19115-1:2014
- Edition
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Version 2.0, September 2018
- Citation identifier
- http://pid.geoscience.gov.au/dataset/ga/122551