Eocene Calcareous Nannofossil Biostratigraphy of the Otway Basin

A study of middle to late Eocene calcareous nannofossil assemblages from four sections in southeastern Australia's Otway Basin. The research deduces a sequence of biostratigraphic events and compares it with foraminiferal zones and New Zealand records. It assesses diachroneity in marine sedimentation and relates ingressions to changes in sea-floor spreading rates.

Use Cases

• Correlate the local highest appearance of the foraminiferid Acarinina primitiva with tropical planktic foraminiferal P. zones (P.13) using biostratigraphic event sequences.
• Analyze the diachroneity of Eocene marine sedimentation by comparing nannofossil assemblage occurrences between the Gambier Embayment and Browns Creek areas.
• Investigate the relationship between major transgressions across the basin and changes in sea-floor spreading rates south of Australia during the middle Eocene.
• Assess sedimentation rates by comparing the thickness of sections between the highest appearances of Cyclicargolithus reticulatus and Discoaster saipanensis at different locations like Browns Creek.

Strengths

• Data derived from a study of four distinct geological sections in the Otway Basin, providing multiple observational points.
• Biostratigraphic event sequence spans from the middle Eocene (lowest appearance of Cyclicargolithus reticulatus) to the latest Eocene (disappearance of Discoaster saipanensis).
• Findings are placed within the established context of tropical planktic foraminiferal P. zones for broader correlation.

Limitations

• Primary data format is narrative text within HTML/PDF publications, not a structured, queryable table or database.
• Sample data and specific columnar data (e.g., fossil counts, precise depths) are unavailable for direct computational analysis.
• Geographic focus is limited to the Otway Basin in southeastern Australia, which may limit direct applicability to other regions.

Provenance

Source

Geoscience Australia Data

Collection Method

Study of calcareous nannofossil assemblages from four geological sections, compared with foraminiferal biostratigraphy.

Time Range

Middle to late Eocene geological epoch.

Freshness

Last updated metadata indicates 2026-03-07, though the underlying study publication date is unknown.

Geography

Otway Basin, southeastern Australia (regions mentioned include Gambier Embayment, Browns Creek, Castle Cove).