In a groundbreaking study, a team of geoscientists, including Dr. Uisdean Nicholson and Dr. Débora Duarte, has uncovered a significant clue about the formation of the Atlantic Ocean. Their research, revealed through seismic profiles and deep-sea core samples, traces the opening of the Equatorial Atlantic Gateway back to 117 million years ago, shifting previous geological timelines. This discovery challenges prior assumptions about the formation of the Atlantic and offers insights into the dramatic tectonic events that unfolded beneath the Earth’s surface long before human existence. The results of this study, published in Global and Planetary Change and reported by Heriot-Watt University, represent a pivotal moment in understanding the tectonic forces that shaped the continents and the oceans.
The Discovery of the Gigantic Mud Waves
The team’s investigation began with the analysis of seismic data and deep-sea drilling cores located more than 3,000 feet below the seafloor, about 250 miles west of Guinea-Bissau. What they found were massive mud waves, some up to one kilometer long and several hundred meters high. These colossal structures are an ancient testament to the violent geophysical processes that occurred millions of years ago when the Earth’s tectonic plates began to drift apart. The sediment waves reveal that the Atlantic Ocean’s formation wasn’t a sudden event but rather a gradual process marked by the movement of dense, salt-laden water.
As Dr. Nicholson explained, “These are one-kilometre-long waves, a few hundred metres high,” comparing them to the towering dunes of the Namib Desert. The immense size of these mud waves speaks to the power of the forces that were at work. The saltwater’s density created a flow capable of reshaping the seafloor in extraordinary ways, scouring and sculpting the landscape beneath the ocean’s surface. This discovery provides a new way of thinking about how oceans might have formed and continues to shape scientific understanding of early Earth history.
Rewriting the Geological Timeline: The Start of the Atlantic’s Formation
The new findings suggest that the formation of the Atlantic Ocean began far earlier than previously believed. Geological models had placed the birth of the Atlantic somewhere between 113 and 83 million years ago, but this new data pushes the timeline back to at least 117 million years ago. This shift is significant because it forces scientists to reconsider how the Atlantic Ocean and the surrounding landmasses—Africa and South America—began to separate.
Dr. Duarte emphasized the importance of the new evidence: “The sediment waves show that the opening started earlier, from around 117 million years ago,” underscoring the fact that the initial outflow of water was powerful enough to rework the seafloor, yet focused enough to leave behind a coherent bedform train. These waves, caused by a massive outflow of brine from evaporating basins, help scientists date the precise moment when saltwater first began spilling over and changing the course of geological history. This new understanding pushes back our understanding of the opening of the Atlantic and redefines the tectonic processes at play.
The Role of Salt-Laden Water in Ocean Formation
One of the most fascinating aspects of the discovery is the role of salt-laden water in triggering the formation of the Atlantic Ocean. Before the ocean fully opened, basins to the south of the gateway had been evaporating under tropical conditions, leaving behind highly concentrated saltwater. When the tectonic barrier finally cracked, the dense brine rushed down the seabed like a submarine waterfall, creating the powerful mud waves that were observed. The research team was able to trace the density-driven outflows with remarkable precision, revealing how the brine spread across the seabed, carving massive waves and reshaping the area.
The dynamics of these dense water flows highlight the incredible power of Earth’s natural processes. The waves themselves, created by the cascading water, serve as a timestamp for one of the most important geological events in Earth’s history—the gradual opening of the Atlantic Ocean. This natural event helped to reshape the oceans and played a crucial role in the long-term evolution of the planet’s climate systems. As the researchers note, these waves were not random occurrences; they were the result of precise, predictable processes that have shaped Earth’s past and will continue to affect its future.
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