The King’s Trough complex, located about 1,000 kilometers off the coast of Portugal, is often referred to as the “Grand Canyon of the Atlantic.” A recent study sheds light on how this massive underwater feature formed.
Experts have long speculated about the origin of this extensive system of trenches and basins, which stretch across 500 kilometers of seafloor. Initially, many believed it was simply due to the pulling apart of the oceanic crust. However, a new study from the GEOMAR Helmholtz Centre for Ocean Research in Germany reveals a more complex picture.
Using detailed datasets, the researchers found that a combination of heat from a nearby mantle plume and significant pressure from a temporary plate boundary led to the formation of the King’s Trough complex (KTC). “Tectonic processes played a crucial role in creating the King’s Trough,” explains marine geologist Antje Dürkefälden from GEOMAR.
To better understand the history of the KTC, the researchers used high-resolution sonar mapping and collected volcanic rock samples from various locations within the trough. This analysis revealed that the KTC likely formed between 37 and 24 million years ago.
They discovered that a plate boundary ran through the area, which contributed to the stretching and fracturing of the seafloor. The mantle plume nearby likely directed this boundary along a path of least resistance, causing the KTC to develop where it did. “This thickened, heated crust may have made the region mechanically weaker,” noted marine geologist Jörg Geldmacher.
While these tectonic forces were considerable, they were not enough to create a complete seafloor-spreading ridge, like the Mid-Atlantic Ridge. Eventually, as the plate boundary shifted south toward the modern Azores, the formation of the KTC halted.
Interestingly, this study connects the KTC to larger geological patterns. The plume identified may be an early branch of the active Azores mantle plume, located about 700 kilometers to the south. This could provide scientists with a living example of how similar underwater features form, influenced by both surface and deep Earth processes.
Understanding the King’s Trough complex can deepen our knowledge of other underwater structures. For instance, the Terceira Rift in the Azores is also a system of trenches in formation, potentially mirroring the KTC’s processes.
The research highlights that these large submarine features remain poorly understood, which invites further exploration. The findings recently appeared in Geochemistry, Geophysics, Geosystems.
For more detailed insights, you can read the full study here.
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