Geologists have shown a vast canyon 621 miles (1,000 kilometers) west of the Iberian Peninsula. Thirty-seven million years ago, a temporary boundary between tectonic plates opened up, dividing the ocean floor of the Atlantic Ocean from east to west.
The discovery recreates one of the ocean’s deepest places crack This is a fossilized trace of a vanished plate edge, revealing how shifting plate boundaries redraw the map of the deep ocean.
hidden atlantic canyon
Located in the far reaches of the North Atlantic Ocean, the Kings Trough stretches for 311 miles (500 kilometers) and reaches a height of 14,764 feet (4,500 meters), forming a series of parallel basins and ridges cut into the thick oceanic crust.
By matching the age of volcanic rocks with cracks in the ocean floor, Dr. Antje Dürkefelden Geomar The Kiel-Helmholtz Center for Ocean Research has demonstrated that this structure opens along the ephemeral boundary between the African and Eurasian plates.
These ages indicate that the valley gradually widened from east to west before tectonic movements moved elsewhere and the valley became stuck in place.
Recognizing this sequence raises deeper questions about why this particular section of the crust was so dramatically destroyed while adjacent areas remained intact.
where the canyon flows
To the far west of Portugal and Spain, kings The trough is approximately 186 miles (300 kilometers) east of the Mid-Atlantic Ridge.
At the eastern end, Peak Strait and Freen Strait plunge nearly 19,700 feet (6,000 meters), making it one of the deepest points in the Atlantic Ocean.
Parallel basins and ridges on either side stretch for hundreds of miles, with some walls rising steeply over short distances.
This canyon requires a tectonic explanation, as such a shape is better suited to tearing or slipping faults than to slow erosion.
Testing the new description
For years, many research teams have treated the canyon as a simple case of the ocean floor stretching as it cools.
The idea envisioned widespread separation, with the same forces acting on entire regions at once.
but, deep The basins were parallel, with the eastern end much more open than the western end, leaving a mystery.
These discrepancies required geologists to test whether it was moving. dish Rather than simply stretching, the border has carved a groove.
moving plate boundaries
dish reconstruction They placed the border between Africa and Eurasia here between 37 and 24 million years ago, and then removed it.
Once that boundary arrived, lateral movement and tension opened the fault, widening the main valley along the moving boundary.
At the eastern end of the Kings Trough, in basins known as Peak Deep and Freen Deep, the extension was cut so deeply that magma rose from the underlying mantle and cooled into fresh lava.
Then the movement of the plates shifted elsewhere, the cracking stopped, and the King’s Trough complex became a long record of that moment.
Undersea date
During the 2020 Meteor Cruise, scientists multi beam sonar To chart the depth of the ocean floor, we use sonar systems that send out acoustic pulses.
Scientists recorded fan-shaped echoes as the ship moved forward and calculated the depth of the ocean floor from the travel time.
Crews dredged lava from a depth of 2 miles (3.2 kilometers), and GEOMAR researchers read its age using argon dating, a clock based on radioactive decay.
These dates are juxtaposed with reconstructions of the plates, showing when the cracks started and stopped.
Chemical clues in lava
The chemical fingerprints divided the lava samples into two groups, with each group indicating a different source within the Earth’s interior.
In the main trough and nearby seamounts, the lava carries extra trace elements that concentrate in the melt, suggesting an anomalous mantle.
The rocks at the Peak and Freen Deep appeared stripped of excess material and were consistent with the normal mantle that feeds most oceanic ridges.
This contrast allowed the researchers to separate the plume-affected crust from the normal crust. even if both exist within one crack system.
destroyed volcanic roots
Long before the cracks began, heat rising from deep within the Earth thickened the Earth’s crust, making the warm rocks more susceptible to breaking under stress.
Geologists call this upwelling mantle plumea long-lived column of unusually hot rock from below.
Its ancient heat source likely influenced early volcanic activity in the Azores and still influences eruptions around the Portuguese Islands today.
“Our results show for the first time why this unusual structure formed in precisely this location,” said Dr. Dürkefelden.
The boundary line jumps out to the south
About 23 million years ago, the plates realigned and the boundary moved south to the Azores-Gibraltar fracture zone at the entrance to the Mediterranean Sea.
With the stress redirected, the fault along King’s Trough stopped slipping, and the canyon began collecting sediment rather than widening.
At the same time, magma supplied by the plume contributed to the construction of the Azores Plateau, showing how quickly hot regions can relocate activity.
This combination of heat and plate movement raises the alarm that a seemingly stable ocean floor can hide slow changes beneath.
current plate movement
Terceira further south lift It has opened near the Azores, carving out a new basin in the thick oceanic crust.
The diagonal elongation and lateral slip fracture the seafloor into several segments, forming deep pockets separated by ridges.
Unlike Fossil Canyon, this fissure still experiences earthquakes and volcanic activity, which can reveal how the fissure grows over time.
Monitoring that updated system could test new models and improve predictions of where future plate boundaries will form.
Kings Trough Timeline
The King’s Trough complex now reads like a timeline linking plate repositioning to deep heating and sudden seafloor ruptures.
Future research could look deeper and extend mapping across the region to test whether other oceanic cracks are also starting in places where heat has already weakened the Earth’s crust.
This research Geochemistry, Geophysics, Earth System.
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