Oldest Cretaceous sequence, Giralia Anticline, Carnarvon Basin, Western Australia: late Ha

Outcrop and well data describe the oldest Cretaceous sequence in the Giralia Anticline, Carnarvon Basin, including a 10-meter-thick basal sand unit and 56 meters of carbonaceous siltstone-mudstone. The sequence contains abundant fossil conifer wood, ichthyosauran bones, and ammonites, with growth-ring analysis suggesting a seasonal humid mesothermal climate. This data, provided by the Australian Ocean Data Network, documents a late Hauterivian-Barremian transgressive pulse recognized across the Australian continent.

Use Cases

• Modeling transgressive and highstand systems tracts based on described sediment composition and biofacies changes.
• Analyzing paleoclimate conditions based on conifer wood growth-ring analysis mentioned in the description.
• Correlating regional stratigraphy based on the late Hauterivian-Barremian age assessment of the Birdrong Sandstone and Muderong Shale.
• Studying marine facies retrogradation and aggradation patterns based on palynomorph and foraminiferal assemblages.

Strengths

• Includes detailed biostratigraphic assessment with specific zone identification (Muderongia australis Zone).
• Describes specific lithological units with thicknesses (e.g., 10 m Birdrong Sandstone, 56 m Muderong Shale).
• Contains analysis of paleoenvironmental conditions, including estimated maximum water depths of less than 50 meters.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• The age of the upper Muderong Shale and a probable Windalia Sand Member is noted as uncertain.

Provenance

Source

Australian Ocean Data Network

Collection Method

Outcrop description and analysis of the Giralia No. 1 well.

Time Range

late Hauterivian-Barremian (Early Cretaceous)

Freshness

Last updated 2026-04-16 08:30:51.026381; freshness should be verified.

Geography

Giralia Anticline, Carnarvon Basin, Western Australia