The African coastline is renowned not only for its breathtaking beauty but also for the powerful oceanic forces that shape its shores. From the discovery of ancient "mud waves" that redefine our understanding of the Atlantic's birth to the towering swells of contemporary big wave surfing spots, Africa's relationship with giant waves is both fascinating and awe-inspiring.
Ancient Mud Waves and the Birth of the Atlantic
The discovery of buried "mud waves" off the coast of western Africa reveals that the Atlantic Ocean was born at least 4 million years earlier than scientists previously thought. These giant waves were found in sediment cores drilled from 0.6 mile (1 km) below the seabed about 250 miles (400 km) west of Guinea-Bissau in 1975, as part of the Deep Sea Drilling Project. The ocean-drilling project confirmed that Earth's surface is broken into rafts of ever-moving tectonic plates.
In further studying these cores, Heriot-Watt University geologists Débora Duarte and Uisdean Nicholson found evidence of huge mud waves in this region, which would have been the last spot to pull apart when Africa and South America split. These waves, each hundreds of feet high and over half a mile (1 kilometer) long, were caused by the mixing of extremely salty water from the southern hemisphere with less-salty water from the northern hemisphere as South America and Africa tore apart 117 million years ago, forming the Atlantic, according to new research published in the June issue of the journal Global and Planetary Change.
The mud waves formed when water from the north and south, with very different salinities, were mixed together following the final split 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," Nicholson said in a statement.
"They formed because of dense, salty water cascading out of the newly formed gateway." Over the eons, more sediment has buried the waves, locking them below the surface.
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Before the Atlantic split South America and Africa for good, the final connection between the two continents would have been a series of deep basins, which were probably lakes, Duarte said in the statement. At that time, the South Atlantic was rich in salt deposits that made its water very saline, while the North Atlantic was less salty. This difference in salinity caused huge currents when the northern and southern Atlantic waters mixed. The currents, in turn, created the enormous mud waves along the seabed. The mud waves were buried beneath sediment over 117 million years, the researchers found.
The existence of these waves 117 million years ago also suggests that the opening of the Atlantic caused Earth's climate to warm, Duarte said. The basins that flooded in the final rifting of South America and Africa were rich in carbon, and the birth of the ocean would have made the sequestering of carbon less efficient. This reduced efficiency led to a period of warming between 117 million and 110 million years ago, the researchers said.
Sunset Reef: A Modern Big Wave Surfing Destination
In contrast to these ancient waves, the coast of Africa is also home to contemporary giant wave events, particularly in the realm of big wave surfing. Located on the southwestern edge of the Cape Peninsula, Kommetjie offers a series of breaks that Bromley describes as the ideal stepping-stones for familiarizing yourself with waves of consequence. Most kids start out at Long Beach. Around the corner are the deepwater points of Outer Kom and Crayfish Factory.
Halfway between these two worlds, in the middle of the ocean, a lump of water is catching a southeasterly breeze and throwing up plumes of spray as it grabs the contours of an offshore reef. The wave rises up, then cascades in slow motion as it barrels toward the channel, exhaling a lungful of spit before it dissipates amongst the kelp beds. Before Dungeons was ridden regularly, Sunset was the benchmark against which the country’s big-wave exploits were measured.
Sunset essentials, as displayed by three-time world champion Grant Baker.
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Located a half-mile offshore, inside a deep and expansive bay, the reef at Sunset is exposed to heavy winds and currents. Due to the break’s position in the bay, the wind is often one of the most challenging factors at Sunset. The southeast offshore is amplified as it blows across the Fish Hoek Valley and out to sea, where the reef is flanked by deep open ocean on either side. The wave was initially deemed surfable only when huge, clean swells coincided with glassy conditions-a meteorological rarity along the Cape Peninsula.
"The crazy thing about Sunset is that it breaks a lot harder than Dungeons," Bee claims. "At Dungeons, you take a hell of a beating for one or two waves, but then it goes into deeper water and lets you go." "A lot of the Cape Town crew have had near-death experiences out there," says Bromley. "I’ve been caught inside and compressed on the reef. I felt like I was stuck in a vacuum: I was trying to swim, but I couldn’t move, and my vest wouldn’t inflate.
Despite Sunset serving as Cape Town’s big-wave entry spot since the 1960s, those who know it best feel that its heaviest has yet to be ridden. "Most of the time, Sunset is just an entry-level, beautiful big-wave spot," says Bromley. "But when it hits the 20-foot mark, it becomes one of the best big-wave spots in the world. There were 30-foot-plus barrels rolling through top to bottom that day."
Matt Bromley, a prominent figure in the modern Cape Town big-wave scene, emphasizes the importance of ocean knowledge in conquering these waves. "The thing about Cape Town is, even on the best days, when the swells come in, it’s never perfect," he says. "It’s a lot of work to get one good wave out there, and you take a lot of beatings to get it. So you really have to learn how to read the ocean. Taking all that knowledge to waves like Jaws or Maverick’s gives you an advantage, because even though those waves are often bigger, they are so perfect and predictable in comparison."
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