Descubren bosque petrificado de 50 millones de años en Río Negro

A call from a rural property owner south of Bariloche set in motion a discovery that would rewrite a chapter of Patagonia's deep past. Eighty kilometers from the city, on a ranch near Pilcaniyeu, researchers from the Paleontological Association of Bariloche confirmed what the initial report had suggested: thirteen fossilized tree trunks, each roughly fifty million years old, lay preserved in the arid landscape of Río Negro. The find emerged from the convergence of sierras and basaltic plateaus—a geographically complex zone where ancient ecosystems had left their mark in stone.

The investigation began when members of the Paleontological Association traveled to the property alongside a patrol from the National Gendarmerie's Environmental Squadron 34. With the landowner's permission, they set about documenting what lay before them. The trunks belonged to conifers and angiosperms—flowering plants—species that had flourished during the Eocene epoch, a geological period spanning roughly fifty-six to thirty-four million years ago. The preliminary analysis placed these specimens squarely within that timeframe, offering a window into a Patagonia radically different from the one we know today.

During the Eocene, the region's climate bore little resemblance to its present character. Where sparse steppe vegetation and semi-arid conditions now dominate, warm and humid air once sustained vast forests. The trees discovered near Pilcaniyeu are remnants of those vanished environments, silent witnesses to a transformation that reshaped the entire landscape. For paleontologists, their location is particularly significant—positioned where mountain ranges meet plateau formations, they illuminate how ecosystems adapted to complex and dynamic geography, and how the transition between cordilleran sectors and Patagonian plains unfolded over millions of years.

The journey from living wood to stone is a process of patient chemistry. For fossilization to occur, a fallen tree must be rapidly buried beneath sediments that halt decomposition. Over eons, mineral-rich water percolates through the wood's tissues, gradually replacing the original organic matter in a process called permineralization. This transformation preserves not only the trunk's structure but sometimes even microscopic details of the grain. Patagonia's geological history—marked by volcanic activity across multiple epochs—created the mineral-rich deposits that made such preservation possible. The region has become home to some of South America's most significant petrified forests, and continues to yield discoveries of scientific importance.

Once the researchers confirmed the site's relevance, they began systematic documentation and protection work. They identified each specimen, photographed the area, and established precise geolocation coordinates for every fossil. This last step proved crucial: knowing exactly where each trunk lay allowed them to connect the remains to the geological formations that contained them, to reconstruct the conditions under which they were preserved, and to plan future research campaigns. The geolocation data also serves a protective function, ensuring the site can be monitored and incorporated into specialized registries.

Samples were extracted following strict conservation protocols designed to prevent damage that might compromise future study. Even small fragments carry information—about wood composition, fossilization conditions, and specimen age. The recovered materials and samples were transferred to the Paleontological Museum of Bariloche, where they now remain under safekeeping as detailed analysis proceeds. The work falls under Río Negro's Provincial Law 3656, which protects cultural and natural heritage, explicitly including paleontological sites as elements of provincial patrimony. The law also establishes mechanisms for investigating such discoveries and encourages the reporting of chance finds with heritage significance.

The research ahead will attempt to identify the exact species represented and to reconstruct the environmental context in which they lived. Each detail extracted from these ancient trunks—the rings that mark seasons long extinct, the cellular structure that speaks to climate and soil conditions—contributes to a more complete picture of how Patagonia's flora evolved and how the region's dramatic environmental transition came to pass. The discovery, born from a single phone call to a rural property, has opened new lines of inquiry into the deep history of the north Patagonian landscape.