Australian National Gravity Anomaly Grid At 435m Resolution

Nearly 1.4 million gravity stations from the Australian National Gravity Database, supplemented by marine data, were used to generate this grid. The grid shows de-trended global isostatic residual anomalies over Australia and its continental margins, derived from observations dating from the 1940s to 2019. Data were processed and quality-checked by Geoscience Australia geophysicists.

Use Cases

• Map subsurface geological structures by interpreting the de-trended global isostatic residual anomaly values.
• Correlate gravity anomaly patterns with known mineral deposits to train models for exploration targeting.
• Model crustal thickness and isostatic compensation using the derived DGIR grid values across the continent.
• Assess data coverage and station density, which varies from 11 km to less than 1 km, for spatial analysis projects.

Strengths

• Integrates nearly 1.4 million ground gravity stations from a national database.
• Provides continent-wide coverage at a consistent 0.00417-degree (approximately 435m) cell resolution.
• Data incorporates decades of observations, from the 1940s to September 2019, from government, industry, and academic sources.

Limitations

• Ground station spacing is inconsistent, varying from 11 km to under 1 km, creating regions of coarse data density.
• The grid is a derived, processed product (DGIR anomalies), not raw gravity measurements, limiting use for certain calibration tasks.
• Temporal coverage ends in 2019, lacking recent observations for change detection studies.

Provenance

Source

Australian National Gravity Database (ANGD) and v28.1 of the Global Gravity grid from Scripps Institution of Oceanography, NOAA, and NGA.

Collection Method

Grid derived by applying near-field isostatic, far-field isostatic, and trend corrections to Complete Bouguer Anomaly data.

Time Range

1940s to September 2019.

Freshness

The underlying observation data is current as of September 2019, though the metadata record was updated in April 2026.

Geography

Australia and its continental margins.