Recent research, including studies published by Heriot-Watt University and a ScienceDirect report, has uncovered colossal structures buried deep beneath the Atlantic Ocean, shedding new light on the birth of this massive water body. This discovery not only confirms earlier theories about the separation of South America and Africa but also suggests the Atlantic may have begun forming earlier than previously thought.
The Mud Waves Beneath the Atlantic
Geologists from Heriot-Watt University and other institutions have been investigating sediment cores drilled over 45 years ago off the coast of western Africa, around 250 miles west of Guinea-Bissau. These cores, part of the Deep Sea Drilling Project from 1975, uncovered surprising evidence of mud waves formed at a critical point in the Atlantic’s formation. These waves are not just geological curiosities—they offer valuable insights into the processes that led to the rifting of South America and Africa.
“Imagine one-kilometre-long waves, a few hundred metres high: a whole field formed in one particular location to the west of the Guinea Plateau, just at the final ‘pinch-point’ of the separating continents of South America and Africa,” said Uisdean Nicholson, a leading geologist on the project.
These waves were the result of a massive mixing of highly saline water from the South Atlantic with the less salty water of the North Atlantic. This intense mixing created powerful currents that led to the formation of the gigantic mud waves now buried beneath the ocean floor.
The Role of Tectonic Movements and Oceanic Rift
The opening of the Atlantic Ocean wasn’t a sudden event but rather a prolonged process marked by tectonic rifting. As South America and Africa drifted apart, the gap between the two continents widened, filling with water that eventually formed the Atlantic. The mud waves are believed to have been created in the final stages of this separation when the connection between the two continents was at its most tenuous.
Before the Atlantic fully opened, the area between the continents was a series of deep, likely lake-like basins. These basins were rich in salt deposits from the South Atlantic, which created highly saline water. Meanwhile, the North Atlantic waters were less salty, leading to intense currents when the two water bodies mixed.
The Climate Impact of the Atlantic’s Formation
The study suggests that the opening of the Atlantic Ocean wasn’t just a geological event—it may have had significant global climate implications as well. The basins separating Africa and South America were rich in carbon. When the Atlantic began to form, carbon sequestration efficiency was reduced, which led to a period of global warming between 117 and 110 million years ago. This warming was likely driven by the release of carbon into the atmosphere as the Atlantic’s creation disrupted previously stable carbon sinks.
“This shows that the gateway played a really important role in global climate change,” said Débora Duarte, a geologist involved in the study. The increase in carbon emissions at this time may have played a key role in initiating a shift in Earth’s climate, one that would lead to the global conditions we recognize today.
Sediment and Geological Evidence
The mud waves were buried under layers of sediment over millions of years, preserving them beneath the ocean floor. These waves are a testament to the dramatic geological forces at work during the time of the Atlantic’s birth. Sediment cores taken from this region reveal a once turbulent landscape, shaped by the violent forces of tectonic plates moving apart. Over time, the waves became covered with sediment, hiding them deep within the ocean’s crust.
The discovery of these mud waves is a critical piece in the puzzle of understanding Earth’s geological history. It challenges previous assumptions about when the Atlantic Ocean truly began to form and provides a clearer picture of the physical processes involved.
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