Bold claim: old data can still rewrite our map of the world beneath us. And this is the part most people miss: decades-old aeromagnetic surveys still hold fresh, actionable geological clues when reanalyzed with modern techniques.
A team of CSIRO geophysicists led by Dr. Clive Foss revisited aeromagnetic data from 1999 to explore a below-ground region in the Northern Territory that researchers informally call the Australia Magnetic Anomaly because its silhouette mirrors the Australian landmass.
Using the 27-year-old dataset alongside contemporary analysis methods, they peered beneath the NT desert surface to uncover hidden features that surface mapping alone cannot reveal.
Why aeromagnetic data helps:
- The NT is often a flat, seemingly featureless landscape, which makes surface interpretation challenging. Subsurface magnetic signals can expose boundaries, layered structures, and orientations of underground formations that aren’t visible from above.
The dataset in focus (catalogue number P1008) comes from one of many archived collections curated by Geoscience Australia. It originated with the 1999 Bonney Well Survey, flown along north–south lines with 400-meter spacing, a nominal terrain clearance of 60 meters, and east–west tie lines 4 kilometers apart.
Dr. Foss notes that earlier magnetic maps were limited by artefacts where flightlines and magnetic structures aligned. His colleague, Dr. Aaron Davis, developed an innovative gridding algorithm that cleans and stabilizes the data, producing crisper, more consistent images. This refinement enabled the team to detect long-hidden features such as geological boundaries and subtle magnetic layers and signatures, shedding light on the shapes and orientations of underground structures.
“By improving data processing and modeling, we can extract more geological information than ever before,” said Dr. Foss.
From old to new: the study and its implications
The study, titled Geomagnetophilia #5: The Australia magnetic anomaly, Northern Territory, was authored by Clive Foss, Aaron Davis, and Sarath Patabendigedara of CSIRO Mineral Resources. It was published in the February 2026 issue of the Australian Society of Exploration Geophysicists’ journal, Preview (available at the ASEG digital library).
The authors point out that many regional aeromagnetic surveys across Australia were originally conducted to produce map images for geological mapping, yet those surveys contain substantial quantitative information about subsurface magnetizations that remains largely untapped. The methods demonstrated in this paper represent just a portion of the techniques that can be applied to Australia’s highly variable datasets, offering a path to richer geological insight from existing data.
