National Gravity Compilation 2019: Airborne DGIR Grid for Australia

Approximately 1.8 million gravity observations, including nearly 1.4 million ground stations and over 450,000 line km of airborne surveys, were used to generate this national grid. The dataset measures variations in gravitational acceleration to reveal subsurface geological structures across Australia and its offshore regions. It represents a multi-decade compilation of data from government, industry, and research sources, processed into a raster with a cell size of approximately 435 meters.

Use Cases

• [Mineral exploration targeting] based on [gravity anomalies indicating subsurface density contrasts from different rock types]
• [Geological mapping and structural interpretation] based on [the processed gravity grid revealing sub-surface geological structure]
• [Integration with other geophysical datasets] based on [the standardized gravity units (gu) and geospatial grid format]
• [Basin analysis and resource assessment] based on [the inclusion of both onshore and offshore gravity data]

Strengths

• Integrates a large volume of observations, including approximately 1.4 million ground stations and 451,000 line km of airborne gravity and gradiometry surveys.
• Combines data from multiple sources and vintages, with acquisitions spanning from the 1940s to the present day, providing historical depth.
• Data quality is explicitly checked by GA (Geoscience Australia) geophysicists to ensure it is fit-for-purpose.

Limitations

• Key metadata such as specific license, exact row/record count for the grid, and detailed column schema are not provided in the available sources.
• The dataset's temporal coverage is broad but imprecise ('1940s to present'), and the 'last updated' metadata field shows a future date (2026), indicating a potential metadata conflict or error.
• Station spacing for ground observations is noted to vary, which may lead to inconsistencies in data resolution across the grid.

Provenance

Source

Geoscience Australia (GA), Commonwealth/State/Territory Governments, mining industry, universities, and research organisations. Offshore data sourced from Scripps Institution of Oceanography/NOAA/NGA Global Gravity grid v28.1.

Collection Method

Ground gravity observations, airborne gravity surveys, and airborne gravity gradiometry surveys, processed via standard methods and compiled into a de-trended isostatic residual (DGIR) grid.

Time Range

1940s to present (with compilation snapshot from September 2019)

Freshness

The underlying compilation is based on data from the Australian National Gravity Database as of September 2019. Platform metadata lists a last updated date of 2026-06-27, which appears to be an administrative or future-dated entry.

Geography

Australia and surrounding offshore regions