Ancient, buried shorelines near Carmen de Patagones, Argentina, may be hiding treasure. Scientists are investigating whether rare earth elements could eventually be mined there, with research council CONICET leading the project.
Their first objective is to identify promising sedimentary zones and create interactive maps for future exploration while providing transparency to the public.
Dark, heavy-mineral sands can point geologists toward concentrations worth testing, but a black beach is not proof of a commercially viable rare earth resource, so this is just the beginning. Samples from the first excavations are still undergoing chemical, geochemical and mineralogical analysis, so the story for now is about building evidence and rules before companies arrive.
Why these minerals matter
Rare earths are a family of 17 elements used in permanent magnets, electric vehicle motors, wind turbines, industrial equipment, data centers, aerospace systems and defense technology. The International Energy Agency says demand for the four main magnet rare earths has doubled since 2015 and is projected to grow by another third by 2030 under current policies.
Supply is also highly concentrated. China accounted for 60% of global mined production of magnet rare earths in 2024, 91% of refined output and 94% of sintered permanent magnet production, according to the IEA. For countries seeking more resilient supply chains, knowing what lies underground at home has become an economic and security question, not just a geological one.
How ancient coastlines trap minerals
Why look beneath an old beach when the modern coastline is easier to reach? The Center for Geological Research, known by its Spanish acronym CIG and jointly operated by CONICET and the National University of La Plata, is focusing on paleocoasts. These are sedimentary environments connected to shorelines that existed roughly 8,000 to 100,000 years ago and are now buried.
Mineral-bearing grains can be much denser than common quartz, allowing waves and currents to sort and concentrate them in particular layers over time. Where those heavy minerals accumulate, they can produce dark or black sands that provide a first visual clue. CONICET says such sands have been recorded around Carmen de Patagones, leading researchers to examine associated paleocoasts instead of targeting today’s beaches and dunes.
Black sand is only a clue
The fieldwork has already produced samples, but the decisive laboratory work is still underway. Researchers are using chemical, geochemical and mineralogical tests to identify the sediment’s composition and measure its heavy-mineral content. That information could eventually show how concentrations vary according to the age and location of each buried coastline.
There is still a big gap between detecting interesting minerals and proving a business case. The official announcement does not include a resource estimate, ore grade, extraction design or economic feasibility study for the area. As project director Ernesto Schwarz explained, the challenge is finding concentrations high enough to make extraction economically workable while keeping environmental effects as low as possible.
Rules before rigs
The proposed interactive maps are meant to do more than guide geologists toward promising ground. CONICET says they could help municipal and provincial authorities prepare public policies, regulations and good-practice manuals before any private company seeks permission to conduct further exploration or extraction.
That early planning is perhaps the most distinctive part of the project. Schwarz summarized the objective as achieving “the lowest possible environmental impact” while preserving the area’s current beaches and dunes. The municipality of Patagones has also helped researchers communicate with local communities and reach paleocoasts buried beneath privately owned cattle land.
Buried does not mean impact-free
Looking beneath former shorelines may reduce direct pressure on active coastal systems, but it does not erase the wider risks associated with rare earth development. The International Energy Agency (IEA) warns that extraction and processing can produce acidic waste, toxic sludge and residues containing concentrated naturally occurring radioactive materials when projects are poorly managed.
That is why the maps alone will not answer whether mining should proceed. They may reveal where concentrations exist, but any future proposal would still have to be judged on its own environmental and economic merits. Maps are a starting point, not a green light.
A test case for Argentina
CONICET notes that Argentina is already an important lithium producer, yet the country has relatively little information about rare earth-bearing minerals across its territory. The Carmen de Patagones work is therefore as much a method-building exercise as a local survey.
It will test how field observations, laboratory data and digital mapping can be combined into a repeatable exploration framework.
Buenos Aires Province has roughly 500 miles of present and ancient coastline between San Clemente del Tuyú and the mouth of the Río Negro. Schwarz said the methodology could eventually be expanded to other parts of Argentina, although no timetable has been announced. There is plenty of ground left to study.
What happens next
The next milestone is not the arrival of construction equipment. It is laboratory confirmation, followed by maps showing how heavy-mineral concentrations vary among buried shorelines and geological ages. Only then could authorities and researchers decide whether more detailed prospecting is justified.
For now, the conclusion is measured but significant. Argentina may have a new route for investigating strategic minerals, and it is trying to put scientific evidence and environmental guardrails in place before treating that possibility as an extractive opportunity.
The official statement was published on CONICET.
