Australian Free-Air and Bouguer Gravity Anomaly Maps at 1:25 Million Scale

The Australian Ocean Data Network provides two geophysical maps of Australia at a scale of 1:25 million. The Free-air Anomaly map and the Gravity Map (showing Bouguer anomalies on land and free-air anomalies at sea) were derived from the same data bank as the 1:5 million 1976 Gravity Map of Australia, with additional marine observations from the 'Gulf Rex' vessel. The maps were drawn by BMR's Geophysical Drawing Office and printed by the Division of National Mapping, Department of National Resources.

Use Cases

• Modeling crustal thickness and density variations based on the Bouguer and free-air anomaly data.
• Integrating marine and terrestrial gravity observations for regional geological studies based on the combined data sources.
• Creating derivative maps for resource exploration based on the smoothed and contoured anomaly patterns.
• Studying the geophysical signature of the Great Barrier Reef region based on the 'Gulf Rex' marine data mentioned.

Strengths

• Maps are derived from a consolidated national data bank, suggesting standardized processing.
• Includes specific marine observations from the 'Gulf Rex' vessel that filled a data gap near the Great Barrier Reef.
• Provides two complementary anomaly representations (Free-air and Bouguer) for analysis.

Limitations

• Data is based on a 1976 source map; geological interpretations may require more recent data for confirmation.
• Column-level documentation is absent; field semantics must be inferred after download.
• The primary data format is PDF/HTML, which may require conversion for computational analysis.

Provenance

Source

Australian Ocean Data Network, derived from Bureau of Mineral Resources (BMR) data.

Collection Method

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

Time Range

Primary data source from 1976.

Freshness

Last updated 2026-04-10 19:10:34.710587; freshness should be verified.

Geography

Australia, including surrounding marine areas.