The role of Brazilian airborne geophysics in the critical minerals and rare earths race

In the global race for critical minerals and rare earths, finding deposits quickly and at low cost has become a strategic advantage. Here Brazil holds an under-used asset: decades of public airborne geophysical surveys, carried out mainly by the Geological Survey of Brazil (SGB/CPRM), covering large portions of the territory with magnetometry and gamma-ray spectrometry. This data is a powerful starting point to vector critical minerals at a regional scale.

Why airborne geophysics is the first filter

Critical minerals are usually tied to geological settings with characteristic geophysical signatures. Instead of walking the field blindly, the explorer uses airborne geophysics to narrow the search area before any drilling. It is a way to look at the subsurface over large areas, including where there is soil cover or dense vegetation.

The signatures of the main targets

• Niobium and rare earths (carbonatites and alkaline complexes): these intrusions tend to produce strong magnetic anomalies and, in radiometrics, thorium (eTh) highs — thorium frequently accompanies rare earth minerals. The combination of a circular magnetic target with a thorium high is a classic vector for carbonatites.
• Lithium and tantalum (pegmatite fields): mineralized pegmatites are hard to detect directly, but they sit in structural and lithological settings that magnetometry and radiometrics help delineate — for example, around evolved granites and shear zones.
• Rare earths in ionic clays: here the mineralization is in the weathering cover over enriched source rocks. Cross-referencing radiometrics (thorium highs) with the digital elevation model (DEM) helps distinguish supergene enrichment preserved on plateaus and hilltops.

The fundamental role of official agencies

This dataset did not appear out of nowhere: it exists thanks to the fundamental role of public agencies. The Geological Survey of Brazil (SGB/CPRM) is the main body responsible for planning, carrying out and publishing the country's airborne geophysical surveys, through territory-mapping programs sustained over decades. Alongside it are state geological surveys — such as CBPM (Bahia) and Codemig/Codemge (Minas Gerais) — and the National Mining Agency (ANM), which organizes mineral tenements. It is also worth mentioning the National Agency for Petroleum, Natural Gas and Biofuels (ANP), which maintains extensive geophysical archives in the energy sector — part of that geophysical knowledge of the territory overlaps with mineral exploration. It is this publicly funded geological-knowledge infrastructure that gives Brazil an edge: the base data has already been acquired and made openly available.

Brazil's edge: abundant public data

Unlike many exploration frontiers, in Brazil the airborne geophysical data already exists and is public. The historical bottleneck is not a lack of data, but the time and expertise to download, process and integrate everything — magnetometry, radiometrics, geology, terrain and mineral occurrences. Done manually, this work can take days per area.

From the race to the target, in minutes

It is precisely this bottleneck that automation attacks. By standardizing processing and automatically integrating official databases, what took days is delivered in minutes — allowing geologists, junior companies and investors to quickly screen areas with potential for critical minerals. In a race where speed and cost matter, turning Brazil's public data into prioritized targets is a concrete advantage.

How Lithogeo helps

This is exactly the kind of work the Lithogeo platform automates. From an ANM process number or a polygon of your area, it processes and integrates the public data — magnetometry, gamma-ray spectrometry, geology, terrain and mineral occurrences — and delivers the products described here ready for analysis, in minutes and right in the browser.

Educational content. The airborne geophysical signature is a support vector: confirming mineralization depends on detailed geology, geochemistry and drilling, always with qualified professionals.