Uranium Redox State Analysis in Cretaceous Marine Shales

Nine carbonaceous shale samples from Australia's Cretaceous Toolebuc Formation reveal 20-30% of uranium persists as U(VI) even under anoxic conditions. Researchers used high-energy resolution fluorescence detection x-ray absorption spectroscopy and nanoscale secondary ion mass spectrometry for characterization. The Australian Ocean Data Network published findings presented at the 2023 Goldschmidt Conference.

Use Cases

• Correlate uranium oxidation state with total organic carbon content (5.9 to 13.4 wt%) across nine shale samples.
• Analyze spatial distribution of uranium associations using NanoSIMS data on organic matter, sulphide, and phosphate minerals.
• Compare uranium speciation in high-TOC shales versus low-TOC coquinite samples (0.3 and 2.4 wt% TOC).
• Model uranium fixation processes using U(VI) proportion data from anoxic marine sediments.
• Support mineral exploration by linking depositional environment (dysoxic vs. anoxic) to uranium redox state proportions.

Strengths

• Uses high-energy resolution fluorescence detection x-ray absorption spectroscopy for precise speciation.
• Includes nanoscale secondary ion mass spectrometry data revealing multiple uranium associations.
• Compares two distinct sediment types: nine organic-rich shales and two coquinites.

Limitations

• Small sample size of only eleven total specimens limits statistical generalizability.
• Geographic scope is restricted to a single formation in the Eromanga Basin, Australia.
• Raw analytical data and column definitions are not provided in the description.

Provenance

Source

Australian Ocean Data Network

Collection Method

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

Time Range

Cretaceous period

Freshness

null

Geography

Toolebuc Formation, Eromanga Basin, Australia