A giant crater discovered in the interior of Piauí revealed, after decades of studies, a rare meteorite impact that transformed the region and impressed scientists worldwide.

Written by Felipe Alves da Silva

Published on 24/05/2026 at 18:12

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Studies confirm that a gigantic crater in Piauí was created by a meteorite impact millions of years ago, placing Brazil among the locations with the most rare and impressive geological formations on the planet

An immense geological structure located in the municipality of São Miguel do Tapuio, in the interior of Piauí, has just gained international recognition after scientists officially confirmed its extraterrestrial origin. The information was published on May 21, 2026, in the scientific journal The Meteoritical Society, responsible for the specialized magazine Meteoritics & Planetary Science. According to information released by the State University of Campinas, the gigantic 21-kilometer diameter depression was caused by the impact of a meteorite millions of years ago.

The discovery placed the formation among the most impressive structures ever identified in South America. Currently, it is considered the second-largest meteorite impact crater on the continent, the ninth officially recognized in Brazil, and the 37th largest in the world.

The study was led by emeritus professor Álvaro Crósta, from the Institute of Geosciences at Unicamp, with participation from researchers at the Federal University of Ceará, Federal University of Santa Catarina, University of São Paulo, as well as institutions in Brasília and São Carlos. The results will also be presented in August 2026 during the annual congress of The Meteoritical Society, in Frankfurt.

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Rocks revealed marks that only appear after extreme impacts from space

Satellite image of the 21-kilometer diameter crater in São Miguel do Tapuio in Piauí caused by meteorite impact. — Satellite record reproduced by Unicamp reveals the circular geological structure located in São Miguel do Tapuio, in Piauí. Scientific studies confirmed that the formation was created after the impact of a meteorite millions of years ago. Image credit:
REPRODUCTION SATELLITE IMAGES/ UNICAMP

To prove that the crater really emerged after the collision of a celestial body with Earth, researchers analyzed sandstone samples collected in the region. The material revealed microscopic deformations in quartz grains, known as “shock features.”

These marks are considered definitive proof of meteorite impact, as they only appear when rocks are subjected to extremely high pressures, something impossible to occur in common geological processes on the Earth’s surface.

In addition, the scientists used topographic data obtained by the TanDEM-X satellites from Germany and Sentinel-2 from Europe. The analyses indicated that the structure could be between 159 million and 267 million years old.

The samples also underwent advanced microscopic studies conducted at the University of Vienna, further reinforcing the scientific confirmation of the spatial origin of the formation.

According to Álvaro Crósta, large circular structures can arise both from internal Earth processes and from collisions from space. However, the deformations found in the rocks practically eliminate any doubt about the meteoritic impact.

“These features only form under very high-pressure regimes and are permanently recorded in the rocks,” explained the researcher.

Isolated region hindered research for almost five decades

Despite being identified in the 1980s, the scientific confirmation of the crater took decades due to the enormous difficulties of accessing the region.

The structure was initially observed in radar images from the Radambrasil Project, but reaching the central part of the crater has always been a challenge for researchers.

Located about 215 kilometers east of Teresina, the area has rugged terrain, thorny vegetation typical of the Caatinga, and practically no access infrastructure.

Over nearly 50 years, Crósta led three expeditions to the site without being able to fully reach the central region — precisely the point where the evidence of the impact would be strongest.

The situation only changed in 2017, when the researcher, accompanied by Marcos Alberto Rodrigues Vasconcelos from the Federal University of Bahia, managed to advance deeper into the area with the help of a local guide familiar with the terrain.

It was during this expedition that the decisive sandstone samples were collected.

Piauí Crater joins the list of the largest impact structures on the planet

Currently, scientists know of about 200 meteorite impact craters scattered around the world. In Brazil, the largest remains the Araguainha Dome, located between Mato Grosso and Goiás, with approximately 40 kilometers in diameter.

Experts believe that the Araguainha Dome was created after the impact of an asteroid about 4 kilometers in diameter approximately 250 million years ago.

Now, the confirmation of the São Miguel do Tapuio structure reinforces the geological importance of Brazilian territory and increases international scientific interest in the northeastern semi-arid region.

Besides the academic value, the discovery can also boost scientific and geological tourism in the region, attracting researchers, students, and curious individuals interested in rare phenomena related to the history of the planet and the universe.

A giant crater discovered in the interior of Piauí revealed, after decades of studies, a rare meteorite impact that transformed the region and impressed scientists worldwide.

Studies confirm that a gigantic crater in Piauí was created by a meteorite impact millions of years ago, placing Brazil among the locations with the most rare and impressive geological formations on the planet

Rocks revealed marks that only appear after extreme impacts from space

Isolated region hindered research for almost five decades

Piauí Crater joins the list of the largest impact structures on the planet

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A giant crater discovered in the interior of Piauí revealed, after decades of studies, a rare meteorite impact that transformed the region and impressed scientists worldwide.

Studies confirm that a gigantic crater in Piauí was created by a meteorite impact millions of years ago, placing Brazil among the locations with the most rare and impressive geological formations on the planet

Rocks revealed marks that only appear after extreme impacts from space

Isolated region hindered research for almost five decades

Piauí Crater joins the list of the largest impact structures on the planet

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