Dr Rowan Martindale of The University of Texas at Austin spotted something extraordinary while hiking through Morocco's Dadès Valley: tiny wrinkle marks pressed into ancient rock formations that shouldn't exist.

These structures are known to have been preserved in turbidites, which are large sediment deposits created by submarine mudflows many millions of years ago. However, these were not ordinary ripple marks.

These rocks originated approximately 180 million years ago in waters that were at least 180 metres (590 feet) in depth underwater beyond the penetration of sunlight.

Wrinkle structures have always been known to be formed through the activities of photosynthetic algae and bacteria in coastal waters in which light penetrates.

Martindale, along with her fellow researcher Stéphane Bodin from Aarhus University, was aware that this finding would need a lot of proof.

First, the scientists proved that the formation of these rocks occurred at great depths; subsequently, they sought to find chemical indicators of any kind of biological processes. The scientists discovered increased amounts of carbon below the folds.

Based on their findings, the scientists concluded that chemosynthetic bacteria settled on the ocean floor, which had been supplied with various materials by turbidite flows. When the level of oxygen decreased due to decomposition processes, these bacteria were able to survive in such an environment.