Uranium Redox State in Cretaceous Marine Shales from Australia

Nine carbonaceous shale and two coquinite samples from the Cretaceous Toolebuc Formation in Australia were analyzed using high-energy resolution fluorescence detection x-ray absorption spectroscopy. The dataset, presented at the 2023 Goldschmidt Conference, characterizes uranium oxidation state and distribution in organic-rich marine sediments. Results indicate a significant proportion of uranium exists as U(VI) despite reducing conditions.

Use Cases

• Modeling uranium redox behavior in anoxic marine environments based on U(VI) proportion data.
• Improving hydrocarbon exploration models using uranium speciation data from organic-rich shales.
• Assessing critical-metal deposit formation based on uranium associations with organic matter and sulphide minerals.
• Evaluating environmental risks of uranium mobilization using data on its uneven distribution at mm to nanoscale.

Strengths

• Total organic carbon (TOC) content is quantified for all samples, ranging from 0.3 to 13.4 wt%.
• Uranium oxidation state is characterized using high-resolution HERFD x-ray absorption spectroscopy and NanoSIMS.
• Results quantify a significant proportion of U(VI) (~20 to 30%) within the samples.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• Data may reflect geographic bias inherent to the single formation sampled.

Provenance

Source

Australian Ocean Data Network

Collection Method

High-energy resolution fluorescence detection (HERFD) x-ray absorption spectroscopy and nanoscale secondary ion mass spectrometry (NanoSIMS).

Time Range

Cretaceous period (specifically Toolebuc Formation).

Freshness

Last updated 2026-06-27 20:00:25.032291; freshness should be verified.

Geography

Toolebuc Formation, Eromanga Basin, Australia.