Free-air and Bouguer Gravity Anomaly Maps of Australia at 1:25 Million Scale

Two geophysical maps of Australia at a scale of 1:25,000,000, prepared from a national data bank. The Free-air Anomaly map and the Gravity Map (showing Bouguer anomalies on land and free-air anomalies at sea) were drawn by P. Moffat and A.J. Maxwell of the BMR Geophysical Drawing Office and printed by the Division of National Mapping. The maps incorporate marine observations from the 'Gulf Rex' vessel to fill a data gap near the Great Barrier Reef.

Use Cases

• Modeling subsurface density variations based on the free-air and Bouguer gravity anomaly data.
• Regional geological mapping and tectonic studies based on the smoothed and contoured gravity fields.
• Integrating historical gravity observations with modern datasets for continental-scale analysis.

Strengths

• Maps are derived from a national gravity data bank, suggesting a consolidated source.
• Includes specific marine observations ('Gulf Rex') that filled a known data gap in the Great Barrier Reef region.
• Detailed methodology and data sources are documented in a referenced publication (Anfiloff et al.).

Limitations

• The underlying data and map creation date from 1976, which may limit relevance for contemporary high-resolution studies.
• Data is presented as static PDF/HTML maps; raw numerical data and column definitions are unavailable.
• The spatial scale (1:25 million) is regional, not suitable for local or site-specific analysis.

Provenance

Source

Australian Ocean Data Network, via data.gov.au. Original maps prepared by BMR (Bureau of Mineral Resources) Geophysical Drawing Office.

Collection Method

Compiled from a national gravity data bank with additional marine survey data.

Time Range

Data compilation and map creation circa 1976.

Freshness

Last updated 2026-06-05 07:19:54.112065; however, the core data is from 1976.

Geography

Continent of Australia and surrounding marine areas.