Uranium Redox State in Cretaceous Marine Shales

Australian Ocean Data Network presents a geochemical analysis of uranium speciation in organic-rich marine sediments. The dataset contains results from high-energy resolution fluorescence detection x-ray absorption spectroscopy on 11 samples from the Cretaceous Toolebuc Formation. Findings were submitted to the 2023 Goldschmidt Conference.

Use Cases

• Analyze the correlation between uranium oxidation state (U(VI) vs U(IV)) and total organic carbon (TOC) content across 9 shale and 2 coquinite samples.
• Model uranium distribution patterns using data on its association with organic matter matrix, sulphide minerals, and phosphate minerals from NanoSIMS analysis.
• Investigate the variation in estimated uranium oxidation state within individual samples, reported as a range of ~20% of U(VI).
• Compare uranium speciation between low-maturity organic-rich shales (5.9-13.4 wt% TOC) and dysoxic coquinite samples (0.3-2.4 wt% TOC).

Strengths

• Includes high-resolution HERFD x-ray absorption spectroscopy data at U L3 and M4 edges.
• Reports quantitative proportions of U(VI) (~20 to 30%) within marine black shales.
• Provides detailed sample characterization including TOC content and organic matter maturity.

Limitations

• Small sample size of 11 total specimens limits statistical power.
• Spatial coverage is restricted to a single geological formation in the Eromanga Basin, Australia.
• Data granularity is unclear as specific column names and raw measurements are not provided.

Provenance

Source

Australian Ocean Data Network, data_gov_au platform.

Collection Method

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

Time Range

Cretaceous period (specifically the Toolebuc Formation).

Freshness

null

Geography

Toolebuc Formation, Eromanga Basin, Australia.