Geochemical Comparisons of Southern Australian Margin Asphaltites

Southern Australian margin asphaltites are compared geochemically and isotopically to onshore source rock analogues from the Albian-Cenomanian Blue Whale Supersequence and the Albian Toolebuc Formation. The dataset includes evidence from carbon isotopes, C30 methylsteranes, C26 norsteranes, and metalloporphyrins, supporting a mid-Cretaceous source hypothesis. The Australian Ocean Data Network published this analysis for the Eastern Australian Basins Symposium in 2001.

Use Cases

• Correlate asphaltite samples to source rock age using carbon isotope signatures and biomarker distributions like C30 methylsteranes.
• Assess depositional environment (e.g., deep-water anoxic vs. shallow marine) by analyzing metalloporphyrin presence and terrestrial plant input indicators.
• Validate genetic links between migrated hydrocarbons and potential source intervals through pyrolysis data from polar fractions.
• Compare geochemical facies across different stratigraphic units like the Toolebuc Formation and the Tiger Supersequence.

Strengths

• Analysis includes multiple geochemical signatures: carbon isotopes, steranes, norsteranes, and metalloporphyrins.
• Direct comparison is made to specific, named geological formations (Toolebuc Formation, Blue Whale Supersequence).

Limitations

• Sample size is unknown and likely small, focusing on specific asphaltite occurrences.
• Data temporal coverage is limited to a single study from 2001, lacking recent updates.
• Geographic scope is restricted to the southern Australian margin and onshore analogue basins.

Provenance

Source

Australian Ocean Data Network

Collection Method

Geochemical and carbon isotopic laboratory analysis of asphaltite samples and source rock analogues.

Time Range

Early Cretaceous (Albian-Cenomanian) source rock focus, study published in 2001.

Freshness

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Geography

Southern Australian margin and onshore analogue basins (Bight Basin, Eromanga Basin).