Fossils of 2.1-billion-year-old stromatolites have been discovered preserved inside marble wall tiles in the entrance lobby of the Federal University of Minas Gerais (UFMG) School of Medicine, according to a university announcement.
Unlocking a 2.1-Billion-Year-Old Geological Secret
The marble tiles, sourced from the ancient Cumbi Quarry in the region of Ouro Preto, contain cross-sections of stromatolites that resemble jaguar fur patterns. According to Professor Martinez, each circular or elliptic mark represents an ancient colony of cyanobacteria that grew vertically in successive layers, accumulating sediments and minerals through gradual calcification. “Each of these marks corresponds to an ancient colony of cyanobacteria that grew vertically, in a process that we can compare to the stacking of coins,” Martinez explained.
Did you know? Long before complex plant or animal life evolved, ancient cyanobacteria altered Earth’s atmosphere by producing oxygen.
When Ancient Seas Covered Minas Gerais
The presence of these marine fossils reveals a vastly different landscape in the deep past. Billions of years ago, shallow and warm primitive seas covered a large portion of what is now the state of Minas Gerais, providing the ideal environment for stromatolite colonies to thrive. The stone utilized in the UFMG medical building’s construction preserves this remote marine ecosystem directly within an active, everyday academic environment.
Scientific Significance and Rarity of the UFMG Fossils
The identified structures rank among the oldest known fossil records in Brazil. Ranging among the oldest specimens globally, these 2.1-billion-year-old deposits document the critical geological era when Earth's atmosphere transitioned to an oxygen-rich environment.
Where to Find the Fossils on Campus
Visitors, students, and faculty members walk past the rare geological specimens daily. The stromatolites remain visible primarily on the marble wall coverings of the main lobby and throughout specific sections of the UFMG School of Medicine library, turning standard university corridors into an informal paleontological exhibit.
Pro Tips for Visiting the Geological Display
- Look for Patterns: Examine the polished cross-sections closely to spot the distinct elliptical and circular rings resembling animal coats.
- Check the Library: Beyond the main hall, explore the library’s circulation areas where additional marble panels display well-preserved layers.
- Respect the Infrastructure: Remember that these walls are part of an active historical building, so observe the stonework without touching or damaging the original surfaces.
Frequently Asked Questions
What exactly are stromatolites?
Stromatolites are layered sedimentary rock structures formed over thousands or millions of years by the growth and metabolic activity of cyanobacteria communities.
How old are the fossils found at UFMG?
The fossils embedded in the marble are estimated to be approximately 2.1 billion years old, dating back to a crucial era in Earth’s early biological history.
Where did the marble come from?
According to research details released by the institution, the dolomitic marble originated at the ancient Pedreira Cumbi in the region of Ouro Preto, Minas Gerais.
Can anyone visit and view the fossils?
Yes, the fossils are integrated into the original marble wall cladding of the main lobby and library spaces inside the UFMG School of Medicine.
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