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

Two 1:25 million scale maps depict Australia's gravity field. The Free-air Anomaly map is a smaller version of an unpublished overlay for a 1976 geological map, while the Gravity Map shows Bouguer anomalies on land and free-air anomalies at sea. Both maps were prepared by BMR's Geophysical Drawing Office and printed by the Division of National Mapping, incorporating data from the 1976 Gravity Map and additional marine observations from the 'Gulf Rex' vessel.

Use Cases

• Analyze regional geological structures based on Bouguer and free-air gravity anomalies.
• Compare land and marine gravity data based on the combined anomaly types.
• Study the southern Great Barrier Reef's subsurface based on marine observations from the 'Gulf Rex'.
• Create derivative geophysical models based on the smoothed and contoured anomaly data.
• Assess historical gravity data collection methods based on the 1976 source data bank.

Strengths

• Includes marine observations from the 'Gulf Rex' vessel, filling a data gap at the southern end of the Great Barrier Reef.
• Derived from the same data bank as the 1:5 million 1976 Gravity Map of Australia, suggesting a consistent source.
• Maps were professionally drawn by BMR's Geophysical Drawing Office and printed by a national mapping division.

Limitations

• Column-level documentation is absent; field semantics must be inferred after download.
• Row count is unknown, which may limit suitability assessment.
• Data freshness should be verified; the underlying source data is from 1976.

Provenance

Source

Australian Ocean Data Network

Collection Method

Prepared from a data bank used for the 1976 Gravity Map of Australia, with additional marine observations.

Freshness

Last updated 2026-05-05 00:46:16.773993; freshness should be verified.

Geography

Australia, including marine areas such as the Great Barrier Reef.