Overview

• Scientists identified parallel tubular structures in marble and limestone from Namibia, Oman, and Saudi Arabia, forming bands up to 10 meters long.
• The structures, measuring about half a millimeter wide and up to three centimeters long, are believed to be 1-2 million years old.
• Researchers suggest the tubes may have been created by microorganisms tunneling into calcium carbonate for nutrients.
• The origin of the microorganisms remains unknown, and it is unclear whether they are extinct or still exist today.
• The findings, published in the 'Geomicrobiology Journal,' provide insights into ancient life and its interaction with Earth's geological history.