Scientists have discovered ancient «wrinkle» patterns in Jurassic rocks in Morocco that were formed deep underwater, far beyond the reach of sunlight. The finding shows that these structures were created by chemical-energy-based microbes, not photosynthetic ones, changing how researchers interpret signs of ancient life. DR ‹ › A new geological discovery in Morocco is changing how scientists understand ancient life in the deep sea. Researchers have identified unusual «wrinkle» patterns preserved in Jurassic rocks in the Central High Atlas Mountains, according to a recent study published in the scientific journal Geology. The discovery was made in the Tagoudite Formation, near the village of Boumrdoul. The rocks contain small ridges and grooves, known as wrinkle structures, measuring from a few millimeters to a few centimeters. Until now, such structures were usually linked to microbes that rely on sunlight and live in shallow waters. What surprised scientists is that these Moroccan wrinkles formed far below the reach of sunlight, at a depth of around 200 meters. Because of this depth, researchers concluded that the structures could not have been created by photosynthetic microbes. Instead, they were formed by chemosynthetic microbes, organisms that survive by using chemical energy rather than sunlight. As the study explains, «given their paleodepth (~200 m), it is unlikely they were formed by photoautotrophic communities». Rocks redefining ancient life in the deep sea The rocks date back about 182 million years, to the Early Jurassic period. At the time, heavy rainfall increased the flow of sediments and organic material into deeper parts of the sea. These sediments, known as turbidites, were deposited by underwater currents. To confirm the biological origin of the wrinkles, scientists examined the rocks using microscopes and chemical analyses. They found high concentrations of carbon just beneath the wrinkled surfaces, a strong sign that microbial life was once present. Although the wrinkle shapes resemble those found in much older, shallow-water rocks, their depth and chemical signature tell a different story. The researchers believe the microbes fed on chemicals released as organic matter broke down in the sediment, particularly sulfur compounds. Normally, microbial mats are destroyed by animals before they can be preserved. In this case, however, toxic chemicals produced during decay likely kept animals away, allowing the structures to harden and become part of the rock record. This discovery is significant because it shows that wrinkle structures do not always indicate shallow, sunlit environments, as scientists once believed. Instead, they can also form in deep, dark waters. The researchers describe this as «a previously overlooked mode of preservation», noting that it opens new paths for studying ancient life.
